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IFT Annual Meetings - Abstracts of Posters & Presentations that Used the TA.XT2 or TA.XTPlus Texture Analysers
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| This list is of publicly available abstracts of research that we have identified that uses SMS' family of texture analysers. The referenced work remains the property of the authors, their institutions and the IFT. Requests for reprints of the posters and should be directed to the authors, their institutions and to the IFT. The abstracts are presented here for the educational purpose of quickly allowing researchers to determine which research has been done using this class of instrumentation. | |||||
| We strongly recommend membership in the Institute of Food Technologists for everyone interested in food science and technology; as well as for their publications Food Technology and The Journal of Food Science. Please learn more about the IFT at their web site: http://www.ift.org | |||||
| If you have research that used our instrument and was presented at the 2005 IFT and it is not listed then please e-mail us and we will be pleased to incorporate the abstract on this list. The abstracts with titles in red text are likely to have also used our instruments in the research because of our understanding of the authors' research and their laboratory equipment, but the instrument attribution on the poster was unclear. | |||||
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18A-23
Effects of gluten, starch tailing and water soluble constituents on dough rheology and biscuit quality
P. Fustier1, A. R. TAHERIAN1,
Flour fractionation-reconstitution procedures were used to study the influence of gluten, starch tailing and water soluble constituents on dough rheology and dimensional as well as textural characteristics of a commercial soft wheat flour. A semi-sweet biscuit recipe (flour, sugar, fat:water of 100:30:8:36 on 14 wt% moisture basis) was used to assess the influence of the 3 constituents isolated from a patent and clear flour grades on dough consistency, hardness, half relaxation time (Tla) and biscuits volume, density, firmness and dimensions. Increasing the gluten content from 9.5 to 13.5 wt% (d.w.b of flour) incorporated into the commercial flour increased dough consistency, hardness and Tla by 3.2, 2.8, and 1.6 times of the original or control flour. In parallel, the biscuit's density and firmness rose by approximately 14.2 and 56.1%, while the dimensional parameters decreased slightly along with increasing gluten. The clear gluten yielded similar trends than the patent flour, but to a lower extend. Starch tailing of the patent and clear added at level of 3, 6, and 9 wt% induced more substantial increment of consistency and hardness to the dough than gluten ,that is,~4.7 and 6.2 times, respectively, versus the control flour. However, it decreased the dough elasticity due to the water binding capacity of this pentosan-rich fraction. The starch tailing rose significantly the biscuit's density and firmness, but decreased its volume. The flour water soluble constituents added at 1, 2.5, and 5 wt% had a negligible effect on the dough and cookie characteristics. However, it contributes to severe dough stickiness. The results of this study suggested that both the rheological properties of the dough and biscuit's characteristics made with commercial soft wheat flour could be modified by the incorporation of the endogenous flour constituents rather than the composition in fat, sugar and water of the recipe..
18A-27
Extended storage stability of wheat flour tortillas with alpha amylase and soy proteins
F. P. BEJOSANO1, J. N. Alviola2, and R. D. Waniska2. (1) Dept. of Soil and Crop Sciences, Texas A&M Univ., 370 Olsen Blvd., Heep Ctr., 2474 TAMU, College Station, TX 77843-2474, (2) Dept. of Soil & Crop Sciences, Texas A&M Univ., 370 Olsen Blvd., Heep Ctr., 2474 TAMU, College Station, TX 77843-2474
Commercially-produced wheat flour tortillas are made with anti-molding additives thus, they are generally shelf-stable in terms of microbial quality. However, loss in textural quality rapidly occurs during storage which limits the storage stability of tortillas. Such occurrence, often referred to as staling is believed to be caused by starch retrogradation and/or loss of flexibility of the protein matrix. This study was conducted to find ways of preserving the textural quality of wheat flour tortillas during storage. The effect of alpha amylase on reducing tortilla staling due to starch retrogradation was studied. The addition of soy proteins to help improve the stability of the protein matrix in tortillas was also investigated. Alpha amylase and soy proteins were added into a standard tortilla formulation. The tortillas were evaluated for their sensory properties, opacity, diameter and specific volume. Texture measurements were done using the two-dimensional extensibility test with the TA-XT2i texture analyzer and the subjective rollability test. Tortillas with alpha amylase had larger diameter than the control. Most of the soy proteins resulted in softer tortillas although some protein isolates reduced tortilla diameter. Marked improvement in the retention of textural quality during storage was noted in tortillas with alpha amylase alone, and in combination with soy proteins. Control tortillas lost flexibility after 14 d. of storage while those with alpha amylase (with or without soy proteins) remain flexible through 28 d. Thus, with the use of these additives, tortillas with extended storage stability can be produced which benefits both the tortilla manufacturers and the consumers.
18D-18
Effect of heat resistant lactic acid bacteria on pork batter shelf life
N. L. RAMÍREZ-CHAVARIN1, E. Ponce-Alquicira1, I. Guerrero-Legarreta2, M. C. Wacher-Rodarte3, A. Totosaus-Sánchez4, and M. L. Pérez-Chabela2. (1) Dept. de Biotecnología, Univ. Autónoma Metropolitana, Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340, Mexico, (2) Dept. de Biotecnología, Univ. Autónoma Metropolitana, Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340, Mexico, (3) Departamento de Alimentos, Facultad de Química, Univ. Nacional Autónoma de México, Ciudad Univ., Mexico D.F., Mexico, (4) Tecnológico de Estudios Superiores de Ecatepec, Subdirección de Investigación., Av. Valle del Mayo esquina Av. Hank González. Colonia Valle de Anáhuac, Ecatepec,
Lactic acid bacteria in foods include cocci of genus Lactococcus, Streptococcus, Pediococcus and Leuconostoc, and bacilli of genus Lactobacillus and Carnobacterium. These bacteria metabolize sugars into organic acids promoting pH decrease. However, they also produce a variety of low molecular weight antimicrobial compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reuterin. When lactic acid bacteria are subjected to temperatures above the optimum growth range, physiological and morphological changes occur resulting in enzyme activity reduction. The objective of this work was to study the effect of heat resistant lactic acid bacteria on increasing shelf life of pork batters. Strains isolated from meat and meat products, previously identified as heat resistant, were inoculated in uncooked pork batters (5% w:w). Once cooked, the product was divided into three batches for microbial, sensory and physicochemical analysis. Samples were vacuum-packed and stored at 4oC for 15 days. Fifty untrained panelists carried out sensory evaluation at day 2 of storage; the analyzed variables were color, overall acceptability, tenderness and flavor. Enterobacteria counts as well as instrumental color (Hunter Lab) and texture (compression) were also analyzed. The control was uninoculated pork batters. Enterobacteria count decreased one log cycle during the first 8 days of storage, constant values were observed from then up to the end of storage; the highest count was 105 cfu/g, below the legal limit accepted by the Mexican legislation for this type of products. Overall acceptability and flavor of inoculated samples were significantly different to control samples, in agreement with other authors who reported improved sensory attributes of cooked meat products previously inoculated with lactic acid bacteria in addition of a decrease of L. monocytogenes and E. coli counts. No significant difference was observed with respect to texture. Conversely, significant differences were observed in color coordinates (Lab) as compared to the control, which showed higher paleness. Inoculation of lactic acid bacteria to uncooked batters would be a means to increase cooked sausage shelf life, decreasing enterobacteria counts without considerably affecting sensory characteristics.
18E-4
Physical and chemical properties of structured lipids synthesized by chemical interesterification of chicken fat and medium chain triacylglycerols
M. C. CHIU, Faculty of Pharmaceutical Sciences, São Paulo Univ., Av. Prof. Lineu Prestes, 580 B.16, São Paulo, 05508-900, Brazil, L. A. Gioielli, Faculty of Pharmaceutical Sciences, Univ. of São Paulo, Av. Prof. Lineu Prestes, 580, B16, CEP 05508-900, São Paulo, Brazil, and R. Grimaldi, Faculty of Food Engineering, Campinas State Univ., Rua Bertrand Russel,s/n, esquina com Josué de Castro, Campinas, 13083-970, Brazil.
MonoUnsaturated Fatty Acids (MUFA) are known to reduce blood cholesterol levels. It has been recommended that MUFA intake be as high as half of the total recommended dietary intake of calories from fat, as a way to reduce the risk of heart diseases. Chicken Fat (CF) can be considered a source of MUFA since they constitute 45 to 50% of chicken fat. Medium-Chain Triacylglycerols (MCT) are mainly composed of octanoic and decanoic acids. They are metabolized more easily and provide less calories than saturated Long Chain Triacylglycerols (LCT). Our objective was to produce Structured Lipids (SL) with better nutri-tive or pharmaceutical characteristics and evaluate them in terms of physical and chemical properties. CF and MCT were blended in ten different proportions and interester-ified. The fatty acid composition of SLs was determined by gas chromatography. Softening and melting points were determined by AOCS official methods and a constant speed texture analyser was used to evaluate consistency of the samples. Solid Fat Content (SFC) was performed by NMR. Melting behaviour was determined by differential scanning calorimetry. The results showed that the interesterified blends presented 12.3 to 60.9% medium chain fatty acids (MCFA), 14.5 to 34.9% saturated fatty acids (SFA), 18.1 to 42.1% MUFA and 6.6 to 15.1% polyunsatured fatty acids (PUFA). Softening and melting points values ranged from -2.1 to 43.1ºC and –2.1 to 46.3ºC, respectively. Consistency was determined at 10°C to 25ºC. SL had a SFC of 22.5% at 10°C, which progressed downward until no solid fat was present (45°C). Chicken fat and SL showed distintct DSC thermograms. The SL with defined character-istics can be used to combine the beneficial dietary effects of the MUFA and MCFA with desirable physical and chemical properties. They can provide specific metabolic effects for application in food products.
18F-2
Analyzing processing procedure by response surface methodology for black rice cookie
J. H. LEE1, G. H. Kim2, and Y. S. Kim2. (1) Dept. of Food Science and Engineering, Daegu Univ., 15 Naeri Jillyang, Gyeongsan, 712-714, South Korea, (2) Division of Food, Biological and Chemical Engineering, Daegu Univ., 15 Naeri Jillyang, Gyeongsan, 712-714, South Korea
Black rice (Oryza sativa L. Indica type) contains high amounts of protein, phytofats, cellulose, minerals, vitamins, and niacin. Anthocyanin pigments in the black rice have been reported to be highly effective in reducing cholesterol levels in humans. Attempts were made to produce a snack having a chocolate image and, at the same time, taking advantage of functional properties of black rice including carcinogenic, mutagenic, and antioxidative activities. Our objective was to investigate the effects of processing variables (sugar type, amount of black rice added, and baking time) on the cookie-making properties using response surface methodology. The cookie dough was aged for 30 min in a refrigerator, and then sheeted to a thickness of 0.4 cm with the help of a rolling pin. The cookies were baked at 180° C for 10 to 14 min in an oven, then cooled to room temperature and packed in airtight bags. Physico-chemical and sensory properties of sample were determined according to central composite design. The pH, specific volume, moisture content, and spread factor of the cookies were influenced by black rice content and type of sugar used. The pH of both dough and cookie increased as the black rice content increased. Specific volume was significantly increased after baking. Lightness significantly decreased as the black rice content increased in both dough and cookie. Redness increased significantly as the amount of black rice increased in both dough and cookie. Hardness was distinctively affected by type of sugar used. The results provided valuable information on developing new cookies with black rice. The models can be used to describe the effect of sugar, baking time, and black rice on dough and cookie characteristics that are very important for new product development.
18F-7
Development and evaluation (physical and microstructural) of dough and bread fortified with F20 fiber
N. GUEMES VERA1, M. I. Reyes Santamarìa2, N. Maldonado-Hernandez2, and S. Soto-Simental3. (1) Instituto de Ciencias Agropecuarias- CICYTA, Univ. Autonoma del Estado de Hidalgo, Av. Universidad s/n C.P., Tulancingo Hidalgo, 43600, Mexico, (2) Instituto de Ciencias Agropecuarias-CICYTA, Univ. Autonoma del Estado de Hidalgo, Av. Universidad s/n C.P., Tulancingo Hidalgo, 43600, Mexico, (3) Centro de Investigación en Ciencia y Tecnología de Alimentos, ICAp, Univ. Autónoma del Estado de Hidalgo, Av. Universidad Km. 1, Rancho Universitario, Tulancingo, 43600, Mexico
Dietary fiber has been shown to aid in cardiovascular and gastrointestinal health, cancer prevention, and weight management. The average population ingests only 3 to 4 g of soluble fiber/day, which is below the recommended daily intake of 5 to 10 g. The aim of this work was to examine different levels of fiber fortification in wheat dough, preserving those functional properties required to obtain Mexican bread products with acceptable quality attributes while having an improved fiber content and texture. Different formulations were prepared containing fiber (F20) as the main component at four different levels (5, 10, 15, and 20%). The structure of dough samples was examined with a light microscope. Chemical (proximate and dietary fiber content) and physical properties (texture, weight, and volume) were evaluated in samples of Mexican-style bread fortified with the fiber. The micrographs of dough samples showed interconnections within the structure, which are probably due to the presence of the fiber. The chemical analysis also demonstrated an increase in fiber content. On the other hand, texture profile was improved as a result of the new formulation, and the bread volume increased from 100 to 110 cm3 as compared to the blank. This study shows that F20 fiber can be used as a novel ingredient in baked products since it has the potential to improve the physical and sensory properties of wheat bread.
18F-13
Effects of processing conditions on the physical properties of Job's tears cake
B. D. SHIN1, F. Hsieh2, E.-H. Kim1, and J.-B. Eun1. (1) Dept. of Food Science and Technology, Chonnam National Univ., Gwangju, 500-757, South Korea, (2) Dept. of Biological Engineering, Univ. of Missouri-Columbia, 1406 E. Rollins St., 254 Agricultural Engineering Bldg., Columbia, MO 65211-5200
More consumers are demanding for natural and/or functional foods. Rice cakes containing functional cereals such as buckwheat and black rice are receiving increased interest. Job's tears (Coix lacryma-jobi var. ma-yuen) have higher protein and fat contents than other cereals. In addition, it has a bioactive compound, coixol, which has anti-inflammatory, anticonvulsant, and muscle relaxant effects. These functional properties create the opportunity of developing a new puffed snack product using a rice cake machine. The objective of this study was to investigate the effects of various cake puffing conditions on the physical properties of the Job's tears cakes. Independent variables were tempering moisture (14%, 15%, 16%), heating temperature (238, 243, 248° C), and heating time (4, 5, 6 sec). The specific volume and color of the Job's tears cakes were measured by the rapeseed replacement method and a Hunter colorimeter, respectively. The breaking strength and integrity of cakes were determined using a Texture Analyzer and a tumbling device. At higher tempering moistures, specific volume of cakes increased with the increase of either heating temperature or heating time. Higher breaking strength was observed when heating at 238° C for 6 sec. The breaking strength increased as heating time and temperature increased, but decreased with increasing moisture contents. The integrity decreased more when tempering moisture increased from 15 to 16% than from 14 to 15%. The integrity decreased with increasing heating temperature and heating time. The lightness of Job's tears cakes decreased with increasing either heating temperature or heating time, but yellowness and redness showed the opposite trend. Tempering moisture, heating temperature, and heating time significantly influenced physical properties of Job's tears cakes such as specific volume, color, breaking strength, and integrity.
18F-21
Increasing the marketability and consumption of soybeans and their components through the development of soy-based food products
M. KATAYAMA and L. A. Wilson. Dept. of Food Science and Human Nutrition, Iowa State Univ., 2312 Food Sciences Building, Ames, IA 50011
In October 1999, the FDA approved a front-label health claim for products high in soy protein, indicating that these foods may help lower heart disease risk. While high-protein soy foods are entering mainstream consumer consciousness and purchase behavior, beany flavors contribute to low consumption of many soy products. The utilization of entire soybean components, including byproducts from soymilk production, can improve human health, soy marketability, and reduce environmental wastes. Our objective was to use Textured Soy Proteins (TSP) and byproducts (okara) from soymilk production to develop, transfer, and commercialize soybean-based food products and technology to benefit the public. Four different TSPs and flavors, with either frying or baking, were used to find the best formulation for a new TSP food product. Two different dried okara powders were used to find the best formulation for a new soy-based snack product. For both studies, a trained descriptive analysis panel evaluated the intensity of aroma, flavor, texture, and color attributes of the products. A focus group was used during the early formulations to define desirable characteristics in products. A consumer preference test was performed for the flavored TSP products. Instrumental and chemical analyses were performed to evaluate color, texture, and nutritional value of ingredients and finished products. The deep-fried, small-sized TSP with chicken-like flavor was the most acceptable product for consumers (less oiliness and more enjoyable crispiness). The okara snack product made from triple-null soybeans gave the best product (less beany flavor and best texture). These results show that the chicken-flavored TSP and an okara-based snack food can be formulated for both Japanese and American markets; however, improvements in surface appearance of the okara product are needed. These products will give a new high-protein product rich in fiber for soy food industries and consumers.
18F-29
Puffing of okara/rice blends using a rice cake machine
M. XIE, H. E. Huff, F.-H. Hsieh, and A. Mustapha. Dept. of Food Science, Univ. of Missouri, 256 William C. Stringer Wing, Eckles Hall, Columbia, MO 65211-5160
The insoluble byproduct of soymilk and tofu manufacture, called okara, is a nutritious, cheap, and rich source of protein (22%) and dietary fiber (15%). The objective of this study was to develop a novel puffed soy rice cake product with blends of okara pellets and parboiled rice. Okara pellets were prepared by extruding a mixture of dried okara and rice flour at a ratio of 3:2 (w/w) with a twin-screw extruder. The experiment was a 3 x 2 x 3 x 3 x 2 factorial design with two replications. Okara pellets and rice were blended in three ratios: 90/10, 70/30, and 40/60 (w/w) and tempered to two moisture contents: 14 and 17%. The blends were puffed at three heating temperatures (221, 232, 243o C) and times (4, 5, 6 sec). The soy-rice cakes were evaluated for specific volume (SPV), texture, color, and percent weight loss after tumbling. All the processing factors had significant effects (P < 0.05) on the quality of the soy-rice cakes, with the exception of two to four interactions. Increases in heating temperature, time, and moisture led to greater SPV, higher hardness, lighter color, and decreased redness and yellowness values. Higher okara content led to lower SPV, higher hardness, darker color, and increased redness and yellowness values. The SPV for the okara pellet percentages of 0, 40, 70, and 90% were 9.80, 5.35, 4.26, and 3.81 mL/g, respectively, while the corresponding hardness values were 1.38, 1.50, 1.47, and 1.56 g, respectively. Respectively, lightness (L) values were 81.5, 70.6, 69.9, and 68.4, redness (a) values were 1.39, 4.65, 5.61, and 6.93, and yellowness (b) values were 14.9, 19.0, 21.6, and 25.5. This study has demonstrated that soy-rice cakes could successfully be manufactured, using a rice cake machine, making it a novel approach to using okara as human food.
18F-32
Total and partial replacement of whole egg with soy-, wheat-, and whey-based egg substitutes in egg noodles
T. J. Herald, H. A. Khouryieh, and F. M. ARAMOUNI. Food Science Institute, Kansas State Univ., Call Hall,
Eggs possess multifunctional properties that enhance food quality. Conversely, consumers and processors find drawbacks in this ingredient. Consumers are concerned over cholesterol and food safety, whereas processors are concerned over the high cost of eggs. Processors are inquisitive as to whether or not egg substitutes can fully or partially replace eggs without significant loss in product quality, while reducing cholesterol and food safety issues. The objective of this study was to determine if whole egg may be totally or partially replaced with soy, wheat, and whey protein-based egg substitutes and still maintain product quality in egg noodles. Egg noodles were prepared by mixing semolina flour with whole egg and/or egg substitutes. Eggs were replaced at either 50 or 100% with soy protein- (46%), wheat protein- (85%), or whey protein- (60, 90, and 95%) based egg substitutes. Water content and mixing times varied depending on the egg substitute used in the formulation. The dough was folded and sheeted twice. The egg noodles were stored at 4 °C for 0, 15, and 30 days. Physical measurements (thickness, texture, color) and cooking parameters (cooking loss, weight gain) were measured at each time interval. Egg noodle (control) had lower cooking loss, firmer texture, higher L* and b* values among days compared to soy- or wheat-based egg substitutes at 100%. Whey-based (95%) egg substitute exhibited the lowest cooking loss and water uptake, firmer texture, and higher L* and b* values among egg substitutes at 50% replacement. Firmness, L* and b* were higher for soy- and wheat-based egg substitutes at 50%, compared to 100% substitution. Whole egg could not be totally replaced with any of the egg substitutes studied in the egg noodles without some loss of quality. However, partial replacement of eggs was competitive in regard to the physical properties evaluated.
36D-6
Development of instrumental methods and data analysis tools for objective textural characterization of extruded food products
L. SAMUEL, H. Dogan, and J. L. Kokini. Dept. of Food Science, Rutgers, The
Textural characterization of foods is a critical aspect of new product development and quality control in the food industry. Texture analysis procedures are generally empirical in nature. For a specific product, the effect of test parameters on the relevance of the data generated must be clearly understood. Variation in test parameters must be minimized for maximum accuracy of results. Objectives of this study included identification of quantitative measures for textural properties of extruded foods through instrumental analysis, and to develop operator independent decision-making tools for reliable and robust interpretation of the experimental data. A wide range of extruded food products were analyzed with the texture analyzer by uniaxial compression and puncture tests (with conical and cylindrical probes). Test parameters studied were probe speed (1-3 mm/sec) and strain level (70-90%). All measurements were done in 20 replicates. Force-deformation curves were analyzed for fracture force, fracture area, gradient, total work, number of peaks and ratio of linear distances. The deformation behavior of the samples under different probes affected the textural information obtained by the different methods. Force-deformation curves from uniaxial compression gave maximum information about the above parameters. Test speed of 1mm/sec and 80% strain level gave most reproducible results. Equations were introduced into the macro to calculate threshold values for the identification of fracture force, fracture area, gradient and peak number. This made the macro operator independent as compared to thresholds based on arbitrary, user defined numerical values. Gradient calculations are also done automatically within the macro. Macros developed in this study proved to be compatible in a wide range of extruded products with different composition, shape and mechanical properties that disintegrate in a similar manner.
36D-7
Textural analysis method development for two-phase food products
L. SAMUEL, H. Dogan, and J. L. Kokini. Dept. of Food Science, Rutgers, The
The composition and morphology of food products influence the quantitative measures of textural properties derived during their mechanical deformation. The focus of textural analysis of two-phase dry food products like cream or fruit-filled snack bites, is to differentiate between the textural properties of each phase (crust and filler). Our objective was to identify test methods and conditions which can objectively differentiate between the textural characteristics of the different phases of such two-phase products. Compression and penetration tests were done to evaluate the extent of textural information that can be obtained for the crust and filler phases. Test parameters studied were probe speed (1-3 mm/sec) and probe diameter (0.5-100 mm). A robust and operator independent macro was developed to analyze the force-deformation curves for various texture parameters. Uniaxial compression failed to deconvolute the properties of the shell and filler phases. During compression, the sealed edges of the crust collapsed, preventing a reliable measurement. The shape of the conical probe resulted in breakage of the sample before penetration. Moreover, as the samples break instantaneously when the probe tip contacts the surface, the results were point specific and did not describe the mechanical properties of the sample as a whole or of the phases themselves. The punch probe was able to differentiate between the resistances to mechanical deformation offered by the two phases. The developed macro identified differences between the mechanical properties of the two phases which was then used to generate useful, reliable information related to their textural properties. Mechanical measurements with different probes showed the importance of selection of appropriate test methods and conditions for textural analyses of two phased products. The introduction of operator independent decision-making tools in the macro made the analysis robust and reliable.
36D-14
Rheological properties of soy protein hydrolysates
B. P. LAMSAL1,
Targeted enzymatic modification of proteins could result in ingredients with functionality tailored to specific food applications. For soy proteins, stronger gelation and high viscosity are preferable in applications for comminuted meat products, soups and gravies. At the same time, baby food applications, yogurts, and soups need less viscous product mix and weaker gelation. We hypothesize that minimal enzyme treatment of soy proteins retains thermo-rheological properties that could have use in target food applications. Our objective was to investigate the effect of minimal protease treatment of soy protein products on such rheological properties as gelation and viscosity. Limited enzymatic hydrolysis (2 and 4% degree of hydrolysis, DH) of soy protein isolate, concentrate, extruder-expelled (EE) flour, and hexane-extracted soy flour was carried out at pH 7, 50° C with endoprotease bromelain in a 250-mL glass reactor and monitored with a pH-STAT. Rheological properties of freeze-dried hydrolysates (10% w/w protein dispersion) was evaluated with RS 150 Haake rheometer. Dynamic shear (1% oscillatory strain, 0.1 Hz) was monitored in a temperature sweep (25 to 90° C, cooled to 25° C), while apparent viscosity was followed through the shear rate of 10 to 500 s-1.The non-treated protein isolate produced strongest gel followed by concentrate, EE meal and flour. Our results showed that soy protein hydrolysates retained their gelling ability even after protease hydrolysis at 2 and 4 % DH. Hydrolysis up to 4% DH caused dramatic loss of gelling ability for all substrates ranging between 8 to 40 fold. Storage modulus (G') increased during cooling after heating to 90° C. G' values at 25° C were in the order: Control > DH2% > DH4%. Power law model provided excellent fit to hydrolysate dispersions showing shear-thinning behavior (n<1). Hydrolysis increased flow index and decreased consistency coefficient resulting in less viscous dispersions. The results suggest that limited protease hydrolysis of different soy protein substrates at low DH results in weaker gels and thinner dispersions. They could be useful in applications utilizing such properties like baby foods, yogurts, and soups.
36D-17
Effects of internal temperature changes and sodium tripolyphosphates on cook losses and textural properties of meats
S. B. UNAL, F. Erdogdu, and H. I. Ekiz. Dept. of Food Engineering,
Polyphosphates, especially sodium tripolyphosphates (STP) are important functional additives used in meat and meat products. Textural properties and cook losses of meats are significantly affected by internal temperature changes and STPs. The STPs reduce cook losses and improve textural properties especially by increasing water holding capacity of the meat proteins. However, the increase in internal temperature enhances meat proteins denaturation and decreases their water holding capacity. Therefore, it is important to determine these changes and effects of internal temperature and STPs on these properties. The objective of this research was to determine the effects of internal temperature, STP concentration and STP dipping time on cook losses and textural properties of meats. The meat samples (2×2×2 cm in size) were dipped in different concentrations of STP solutions (2, 4 and 6%) for different times (0, 10, 20, 30 minutes) and cooked in boiling water for 0, 5, 10, 15 minutes. Internal temperature changes were determined using analytical solutions. Thermal properties of meats were determined based on their moisture content via the equations found in the literature. Cook losses were calculated from weight changes, and textural properties were determined using texture profile analysis in Texture Analyzer TA-XT2i (Stable Micro Systems). STPs decreased cook losses and hardness in meats while the increase in STP concentration increased springeness and cohesiveness values. Increases in internal temperature resulted in higher hardness, gumminess, chewiness and cook loss values. In addition to these, cook losses and hardness values were the highest in meats that were not treated with STPs before cooking. The results showed that the STP concentration and the internal temperature changes affected the textural properties and the cook losses in a great manner. These results may be used for a further meat processing optimization studies when they are correlated with sensory data.
36D-18
Development of capillary extrusion viscometer for the viscosity measurement of fish protein paste
J. W. PARK, Dept. of Food Science & Technology, Oregon State Univ., OSU Seafood Research Lab., 2001 Marine Dr., Rm. 253, Astoria, OR 97103 and B.-Y. Kim, Dept. of Food Science & Technology, Kyung Hee Univ., Seochun 1, Yongin, South Korea.
Viscosity often determines the flow of products and controls the productivity. However, due to the nature of fish muscle proteins (surimi) that easily entangle upon setting or heating, the viscosity is not properly measured using an ordinary Brookfield viscometer. In addition, the dilution factor of surimi paste without salt does not show a linear relationship with a viscosity value. As a result the quality control to oversee the production flow is not easily maintained. Consequently, there is a significant need for a quick and easy method to determine viscosity of fish muscle proteins. Objectives were to develop a capillary extrusion viscometer and equations for measuring the viscosity of fish protein paste. We further wanted to estimate the quality of gel texture using the viscosity values. A capillary extrusion viscometer with a plunger (tube length: 3 and 1 cm, tube diameter: 6 mm) was developed. This viscometer was attached to a TA Plus texture analyzer (Stable Micro System). The viscosity of surimi paste was measured as a function of moisture content(75-80%), salt content (2-4%), and egg white content (2-4%). Each value was also compared with fundamental dynamic values measured using Bohlin CS50 dynamic shear rheometer. As moisture, salt, and egg white contents increased, viscosity gradually decreased. These viscosity values, obtained using our new capillary extrusion viscometer, were well correlated to those values measured using dynamic shear rheometer. The viscosity values showed a reversible relationship with gel failure properties of surimi gel, especially shear stress from the torsion test. This easy viscosity measurement can effectively facilitate production control of comminuted muscle food, including surimi paste. Based on simple linear equations, the viscosity values could be used to quickly and easily to predict final gel quality.
36D-22
Structure-property relationships in amorphous starch matrices
L. Castro, P. Bouchon, and J. M. AGUILERA. Dept. of Chemical and Bioprocess Engineering, Pontificia Univ. Católica de Chile,
Although most engineering properties of foods depend on their structure no clear relationships are usually derived, as is the case of textural properties and microstructure of dry cereal products. The objective of this work was to relate microstructural features of a simple dry starch model to mechanical parameters and fracture mechanism as a function of water activity and drying temperature. A pregelatinized potato starch suspension (23% w/w) was dried into strips at temperatures between 65-105ºC to induce different microstructures. Probes were equilibrated to water activities (aw) in the range of 0.00 to 0.75 and analyzed for mechanical properties and glass transition temperature. From the force-deformation curves two textural parameters were calculated: Maximum Force at Breakage (MFB) and Work to Fracture (WF). Images were obtained by light and scanning electron microscopy, and main features (e.g., bubble size, thickness) quantified by image analysis. Probes dried at high temperature were thicker and less dense than those dried at low temperatures, and contained several bubbles of increasing mean size. Mechanical parameters for all samples were similar and low at aw below 0.44-0.65, but increased drastically above this range and depended strongly on the drying temperature. For example, WF and MFB decreased 12 and 5 times, respectively, as drying temperature increased from 65º to 105º C. The fracture behavior changed from brittle to ductile in the mentioned aw interval, as studied in real time by coupling videomicroscopy to the mechanical assay. Glass transition temperatures of samples at the same water activity were similar. It is concluded that: 1) several microstructures, hence, different mechanical behaviors may be induced by drying the starch model; 2) water activity has a dramatic effect on mechanical properties and observed fracture mechanism, and; 3) the glass transition temperature itself is not a good predictor of the mechanical properties of the system.
36D-32
A novel non-invasive method to measure viscoelastic properties of cereal grains during processing
D. C. GONZALEZ, B. Mert, O. H. Campanella, and M. R. Okos. Dept. of Agricultural & Biological Engineering, Purdue Univ., 1146 Agricultural & Biological Engineering Bldg., West Lafayette, IN 47907-1146
The palatability of cereal grain foods is often increased with the addition of sugars during the cooking process. However, the role of sugars and the mechanisms in which they influence the physical and rheological properties of cereal grains after cooking and upon further processing is not well understood. Therefore, the effect of sugars on starch reassociation (e.g. retrogradation) during further processing (e.g. tempering) was investigated. Tempering was chosen because it is a common processing step used in the production of cereals from grain and it is associated with starch retrogradation. The cooking process consisted of cooking cereal grains (wheat and corn) with an amount of water 1:1 by weight in a pressure cooker. Eight grams of sucrose were added per every 100 grams of cereal grain for the cooking process. Similarly, 8 grams of High Fructose Corn Syrup (HFCS) were added for every 100 grams of grains. The effect of a combination of sucrose and HFCS was also studied (4 grams of each sugar per 100 grams of grain). A control containing no sugar was also tested. The cooked cereal grains were dried to moistures of 20% and 15%. The tempering process consisted of packing the dried grains into sealed containers and holding them for equal amounts of time until moisture was equilibrated. The rheological changes occurring during the tempering process for the cereal grains were monitored by a broad band oscillatory squeezing flow method developed in our laboratory. The method is based on the measurement of the mechanical impedance of the sample. This mechanical impedance is closely related to the sample's viscoelastic properties. Both viscous damping and elastic stiffness values increased with increasing tempering times in all cases examined. Cereal grains cooked with sugars exhibited the greatest increases in hardness supporting the role of these ingredients in promoting retrogradation.
36D-36
Effect of moisture content at harvest of various kernel thickness fractions on rice instrumental texture properties
M. I. SALEH, J. -F. Meullenet, T. J. Siebenmorgen, and L. Wang. Dept. of Food Science,
Thickness rice fractions vary in their protein, lipid, crude fiber and starch contents. This variation in chemical composition is expected to lead to differences in functional properties of cooked rice. The objective of this study was to determine the effect of rice thickness fractions, harvested at different moisture contents, on rice texture properties. Wells and Francis rice cultivars from two locations and of high and intermediate Harvest Moisture Content (HMC) were fractionated using a Carter-Day-grader to small, medium, and large thickness fractions. Milled rice dimensions were measured using a Satake rice image-analyzer RIV-1A (
36E-23
Biochemical changes of stored soybeans and its effect on soymilk and tofu quality
J. Y. L. KUAN and L. A. Wilson. Dept. of Food Science and Human Nutrition, Iowa State Univ., 2312 Food Sciences Building, Ames, IA 50011
Post-harvest modification of soybeans is very pronounced in the summer months, especially during storage and transporting across continents. Over prolonged storage, soybean seed quality and quality of edible products made thereof decreases. The objective of this study was to observe the biochemical changes that occur during soybean storage and its effects on soy food quality, particularly soymilk and tofu. Three different soybean cultivars from two crop years were stored at different temperature (20, 30, 40o C) and humidity (75% RH, 32% RH) combinations for 0-12 months. Soybeans were analyzed for color (HunterLab), oxalates (enzymatic assay), antioxidants (PhotoChem), sugars (HPLC), and processed into soymilk and tofu (Japanese method). With increased storage time, temperature and humidity, soybeans had lower Hunter L values (darker), as browning of the soybean seed coat was observed. This in turn carried over into soymilk and tofu produced from these soybeans. At elevated temperatures and humidities, most proteins have degraded, confirmed by the soymilk not coagulating after 6-9 months of storage. Environmental factors and genotype accounted for the differences in oxalate concentration in the soybeans. Antioxidants in soybeans, when stored at a higher temperature and humidity, had an increased concentration, which could be attributed to the conversion of isoflavones (an antioxidant) from the malonyl to aglycone form. Soybean soluble sugars, although present in small amounts, are important, especially oligosaccharides and reducing sugars. Glucose was only found under high temperature and humidity storage conditions, which suggests complex oligosaccharide breakdown. Sucrose remained relatively stable at all storage conditions, indicating that sucrose was not consumed in Maillard browning reactions. Biochemical changes were also observed within each cultivar based on crop year and environmental factors. Based on these results, storing soybeans under low moisture and temperature conditions are recommended in order to have quality soy products with good functional properties and economic viability.
36E-30
Effects of a combination of £^-irradiation and 1% CaCl2 treatment on quality characteristics and microbiological shelf life of diced red bell peppers
W.-L. CHOU1, A. Prakash2, R. L. Pilling1, and D. M. Foley3. (1) Dept. of Physical Sciences, Chapman Univ., One University Drive, Orange, CA 92866, (2) Dept. of Food Science and Nutrition, Chapman Univ., 1 University Dr., Orange, CA 92866, (3) Dept. of Biological Sciences, Chapman Univ., 1 University Dr., Orange, CA 92866
Diced red bell peppers are becoming popular in retail and food service markets, however, their shelf-life is limited to a few days. Low-dose irradiation is known to improve microbiological quality of fresh produce but, in some products, irradiation can result in softening of the fruit and vegetable tissue. Calcium treatments have been shown to improve firmness by reducing solubilization of pectic substances. The objective was to determine the effects of combined irradiation and 1%CaCl2 treatment on the shelf life properties of diced red bell peppers. Diced red bell peppers were dipped in 1%CaCl2 for 1 minute and subjected to ?- irradiation at 1kGy from a Co60 source. The control, CaCl2 dipped, irradiated, and combination treated samples were stored at 4¢XC and analyzed for changes in texture (Kramer Shear), microbial loads (total aerobic count, and yeast & mold), headspace gas concentrations, polygalacturonase activity, pH and color. Calcium treatment alone increased the firmness of diced red bell peppers by 15%. However, calcium treatment was not effective in diminishing the loss of firmness due to irradiation. Irradiation alone as well as the combination treatment were highly effective in reducing microbial counts. Color was not affected by calcification, but increased in L, a, b values following irradiation. Headspace CO2 production was suppressed significantly (P<0.05) at day 1 in calcium treated samples, but not affected in both irradiated samples. Sensory evaluation is necessary to determine if the loss of firmness due to irradiation is acceptable to consumers. Also, a lower irradiation dose and/or the use of other firming agents that can mitigate the effects of irradiation should be tested to optimize the microbial quality and shelf-life of diced red bell peppers.
36E-31
Effects of calcium ascorbate, an antioxidant and antibrowning agent, on radiation resistance of L. monocytogenes and quality of “Gala” apple slices
X. FAN1, K. B. Sokorai1, C. H. Sommers1, B. A. Niemira1, and J. Mattheis2. (1) Food Safety Intervention Technologies Research Unit, USDA-ARS-Eastern Regional Research Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038-8598, (2) Tree Fruit Research Lab, USDA, ARS, 1104 N. Western Ave, Wenatchee, WA 98801
Ionizing radiation exerts its effect mainly through the free radicals generated from radiolysis of water. Antioxidants may scavenge the radicals, negating or reducing the impact of irradiation on pathogen inactivation and on product quality. This study was conducted to evaluate the impact of calcium ascorbate (CaA, an antioxidant and antibrowning agent) on the radiation resistance of L. monocytogenes inoculated into CaA solutions and on apple slices, and to investigate the effects of irradiation and CaA on quality of ‘Gala' apple slices. The radiation resistance of L. monocytogenes artificially inoculated in 0, 3.5 and 7% CaA solutions and on apple slices that had been treated with the three levels of CaA were analyzed. Non-inoculated apple slices treated with 0, 3.5%, and 7.0% CaA were exposed to 1.6 kGy gamma radiation (a dose equivalent to at least 5-log reduction in L. monocytogenes). Quality was analyzed during 14 days of modified atmosphere storage at 4° C. Results showed that CaA significantly increased radiation resistance of the pathogen both in solution and on apple slices. CaA at levels of both 3.5 and 7.0% prevented the browning of the apple slices. The apple aroma intensity, however, decreased as the concentrations of CaA increased. Irradiation at 1.6 kGy did not significantly affect color, soluble solid content, titratable acidity, or apple aroma intensity. The only negative effect of irradiation on apple slices appeared to be a loss of firmness. However, firmness of irradiated samples treated with 3.5 or 7.0% CaA was always similar compared to the non-irradiated samples that were not treated with CaA. CaA protected L. monocytonenes from radiation both in solution and on apple slices, but radiation at doses sufficient to inactivate a 5-log of the bacterium did not have a significant influence on product quality attributes except the loss in firmness.
36E-33
Textural properties of malic acid incorporated carboxymethyl cellulose and soy protein isolate coatings on alfalfa and mung bean sprouts on storage at 4 oC
K. H. TRAN, N. S. Hettiarachchy, and
Texture plays an important role in fresh produce. A difference from the textural property norm could lead to consumers? rejection of the produce. Carboxymethyl cellulose (CMC) and soy protein isolate (SPI) have been used for years as an edible coating for fresh fruits and vegetables? protection. The incorporation of malic acid into the edible coating solutions is assumed to assist in the textural property?s preservation and extension of alfalfa and mung bean sprouts? shelf-life. Our objectives were to incorporate malic acid into the CMC and SP edible film coating solutions and coat the alfalfa sprouts and mung bean sprouts and to determine the textural property of sprouts. The edible film coating solutions were formed using CMC (for alfalfa) and SPI (for mung beans). The sprouts were dipped into the film coating solutions, dried at ambient temperature, and kept at 4 o C for a week in a plastic bag. The texture of the sprouts was determined using the TA-XT2i Texture Analyzer for puncture force and shear force. Our results showed that the malic acid incorporated edible film coating solutions had preserved the texture of the sprouts. The CMC (0.5 g) and SPI (2 g) coating solutions showed higher hardness force (N) (1.2 and 14.62, respectively) during storage compared to other concentrations of CMC (0.25 g and 0.75 g) and SPI (1g and 4 g) (0.52, 0.88 and 11.56, 14, respectively). These results indicate that the coated sprouts maintained their quality in texture at these concentration levels. The results suggest that malic acid incorporated with CMC and SPI film solution preserves the texture and extend the alfalfa and mung bean sprouts? shelf-life.
36E-62
Osmotic dehydration of guavas in sucrose and maltose solutions with calcium addition
L. M. Pereira1, R. L. Cunha, H. M. A. B. Cardello, M. D. Hubinger1, and M. CRISTIANINI1. (1) Dept. of Food Engineering, State
Sucrose solutions are commonly employed as osmotic agent in fruit dehydration process, however the use of others sugars, like maltose, has appeared as a good alternative due to its protective effect on the structural properties and color stability. Calcium salts are also been used in osmotic solution in order to preserve the processed tissues structure, resulting in products with better texture characteristics. The osmotic dehydration of guavas (var. Paluma) in sucrose and maltose solutions, with calcium lactate addition was studied to verify the effects of these two different disaccharides and of calcium ion on color (L*, a* and b*), texture (stress and strain at failure, relaxation time and residual stress) and sensory acceptance of dehydrated fruits. Three concentrations of the sugars (40, 50 and 60º Brix) and six concentrations of calcium lactate (0 to 1.5%) were employed and the osmotic process was carried out at 40º C during two hours. The sugar type was the more important variable in guavas characteristics, showing a strong influence on color and texture of fruits as well as on sensory acceptance. The guavas color was also influenced by sugar concentration and calcium lactate addition was determinant on guavas texture. The guavas osmotically dehydrated in sucrose solution had better sensory acceptance than the fruits treated with maltose solution independent on sugar concentration and on calcium addition, although all samples studied were accepted by the consumers.
36E-64
1-MCP post-harvest effects on cantaloupes and watermelons harvested at different maturity stages.
J. E. VILLARREAL and L. Cisneros-Zevallos. Dept. of Horticultural Sciences, Texas A&M Univ., 202 Horticulture and Forestry Science Bldg., 2133 TAMU, College Station, TX 77843-2133
The use of 1-methylcyclopropane (1-MCP) treatments has shown to delay quality changes during storage on different horticultural products, including cantaloupes and watermelons. Some factors that may affect the response to treatments include the 1-MCP dose and the produce maturity stage. Selecting appropriate produce maturity stage is critical, since it will potentially allow to optimize the 1-MCP treatment benefits. The objective of this study was to determine the effect of physiological maturity of cantaloupes and watermelons on quality changes when treated with different doses of 1-MCP after harvest. Cantaloupes
36E-71
Extending shelf-life of fresh-cut apples by using whey protein coatings with ascorbic acid, citric acid, calcium chloride, and potassium sorbate
K. I. MATSOS, U. V. Lay, and J. D. Floros. Dept. of Food Science, The Pennsylvania State Univ., 111 Borland Lab, University Park, PA 16802-2504
The limited shelf-life of fresh-cut fruits is the main barrier of the wide commercialization of such products. Chemical treatments and the use of whey protein edible coatings have been shown to delay rapid quality deterioration of minimally processed fruits. However, the combined effect of different active compounds, carried by whey protein coatings, on fresh-cut product quality (color and texture) and microbial decay has not been studied in depth. Our objective was to study the effect of ascorbic acid (AA), citric acid (CA), calcium chloride (CaCl2), and potassium sorbate (PS) in whey protein coatings on the quality (color and texture) and microbial decay of fresh-cut apples. Apple slices (var. red delicious) were dipped in whey protein coating solutions of various AA, CA, CaCl2, and PS concentrations, according to a central composite experimental design. The slices were punctured and inoculated with Penicillium expansum. The samples were stored for 4 weeks in plastic bags at 5° C. The color, texture and microbial growth were evaluated over time. The presence of the coating reduced surface browning of apple slices. Addition of PS in the coating appeared to have a dramatic negative effect on both the color and texture of the product. The effect of PS on product quality was so severe that masked any possible positive effects from other compounds (e.g. AA). CA also appeared to have a negative effect on the color of the product. Regarding microbial growth, PS concentrations above 1.1% inhibited microbial growth for at least 21 days. The above results suggest that whey protein coatings delay color changes of fresh-cut apples. Addition of PS inhibits microbial growth on contaminated surfaces. However, due to its severe negative effect on product quality, PS should be replaced by another antimicrobial agent.
36E-73
Influence of osmotic dehydration, ripeness and frozen storage on physicochemical, optical mechanical and sensory properties of mango fruit
A. Rincon, Food Science and Technology, Univ. of Georgia, Food Science Building, ATHENS, GA 30605 and W. L. KERR, Dept. of Food Science and Technology, Univ. of Georgia, 122 Food Science Bldg., Athens, GA 30602-7610.
There is much demand for high-quality minimally processed fruits for food formulations. The flavor and texture of mango is difficult to maintain in normal drying or freezing operations. Partial osmotic dehydration prior to freezing is an effective way to reduce water content and thus minimize cellular damage incurred during freezing. The objectives of this study were first, to analyze the effect of initial ripeness, sucrose syrup concentration and frozen storage time on the physicochemical, optical and textural properties of mango slices; and second, to assess the sensory properties of treated mangoes by a trained panel. Mango fruit was classified into three categories of ripeness (cutting force 3kg <, 3-4.9 kg, 5kg >), cut into 1.5 cm slices and immersed in sucrose syrups (10-30° Brix) at 20° C for 4 hours. Treated samples were frozen in a blast freezer at –18° C. Moisture loss, soluble solids content, vitamin C, lightness (L*), and hardness were evaluated over 20 weeks of frozen storage. Descriptive sensory terms were developed and evaluated by a trained panel. Moisture loss and soluble solids increased with syrup concentration. Vitamin C, L* and hardness decreased with increasing ripeness, storage time and syrup concentration. Sensory analysis showed that treatment with 30° Brix syrups produced firm pieces with highest sensory scores for sweetness and mango-like flavor. These results suggest that partial osmotic drying with sucrose syrups can produce frozen mango pieces with more fresh-like attributes.
36E-76
Effect of minimally processing and 1 methylcyclopropene on respiration rate, color and texture of guava fruit (Psidium guajava L) cv Media China
G. R. ORTIZ-HERNÁNDEZ1, E. López-Enríquez2, C. Saucedo-Veloz3, and E. Mercado-Silva1. (1) Dept. de Investigación y Posgrado en Alimentos, Univ. Autónoma de Querétaro, Centro Universitario S/N, Querétaro, 76010, Mexico, (2) Dept. de Investigaciòn y Posgrado en Alimentos, Univ. Autónoma de Querétaro, Centro Universitario S/N, Querétaro, 76010, Mexico, (3) Colegio de Posgraduados, Montecillo, Estado de México, Texcoco, Mexico
Because of overproduction of guava in México, new markets are needed as well as developmental work to control the ripening process and allow for a longer distribution time. Our objectives were 1) to measure the physiological response in guava which is minimally processed and stored at different temperatures and 2) to analyze the effects of 1 Methylcyclopropene (1-MCP) on the ripening process of intact fruit. Guava ripe fruits were peeling (1 min in NaOH 2% at 85° C), washed and stored at different temperatures (0, to 15° C) under wet air flow. Every three days the respiration rate was measured by gas chromatography. In other experiment, mature green guava fruit were treated with an air flow with 1-MCP (0-1.2 ppm) for different times (0-5 h); after the fruit was stored at 10° C under an air flow wet during 30 days. Every 4 days the color (hue value) and penetration force (N) was measured using a texture analyzer. After seven days of storage, the respiration rate in all fruit minimally processed was three to eight times higher than respiration rate of intact fruit (50 mL CO2/ kg h) indicating high sensibility of this fruit to minimal processing; at 0° C the respiration rate reached 457 mL CO2/ kg h. The application of 0.6 ppm of 1-MCP during 3-5 h in mature green fruit and stored at 10° C for 30 days, delayed the color changes (hue value 84) and maintained high the penetration force (13N) in comparison with control fruit (hue value 79 and penetration force 4N). The minimal processing in guava fruit increased strongly the metabolism decreasing its potential use in this fruit. However, the application of 1-MCP showed possibilities to increase the shelf life of intact fruit and to facilitate their distribution
36E-82
Alginate coatings for the preservation of minimally processed Gala apples
G. I. OLIVAS1, D.
Edible coatings made from alginate were investigated for their ability to preserve the quality of minimally processed Gala apples. Apple wedges were immersed in a calcium chloride (CaCl2) solution and subsequently coated with one of three different coating formulations: alginate, alginate-acetylated monoglyceride-linoleic acid, and alginate-butter-linoleic acid. Apple wedges were stored at 5°C and 85% Relative Humidity (RH). Weight loss, color, texture, volatiles profile, microbial load, titratable acidity, and soluble solids were assessed over ~9 days of storage. Alginate coatings prolonged the refrigerated shelf life of cut apples. All studied coatings minimized weight loss during storage, however, apples with coatings containing acetylated monoglyceride remained the closest to their original weight. Hardness of coated apples remained practically constant during storage regardless of the type of coating, while control apples had a large decrease in hardness during storage. Browning of apple slices was retarded in coated apples. It was also demonstrated that the studied coatings did not cause anaerobic respiration. A higher production of some typical aroma volatiles 1-butanol, hexanal, trans-2-hexenal, and 1-hexanol, was observed on coated apples presumably due to the metabolization of fatty acids contained in the coatings. No effects from the applied treatments on microbial load, titratable acidity, or soluble solids were found. The use of alginate coatings for the preservation of minimally processed fruits is a promising technology that can improve the quality of fresh products and increase their shelf life and stability.
36E-84
Quality comparison of apple cubes blanched with infrared and steam heating
Y. ZHU, Dept. of Food Science and Technology, Univ. of California, Davis, Bainer Hall 1330D, One Shields Avenue, Davis, CA 95616 and Z. Pan, Processed Foods Research Unit, Western Regional Research Center, USDA, Agricultural Research Service, 800 Buchanan St., Albany, CA 94710.
The blanching process is widely used for inactivating enzymes that are responsible for causing quality deterioration of fruits and vegetables during storage. Typically, it is achieved by using hot water or steam. However, they are energy intensive processes and water and condensed steam can result in leaching of nutrients. It is important to seek alternative blanching technologies with high energy efficiency and without using water and steam. Using Infrared Dry Blanching (IDB) technology could inactivate enzymes with high energy efficiency and no leaching of solids and nutrients compared to hot water and steam blanching. The objective of this research was to study the quality characteristics of blanched apples with IDB and steam. A catalytic flameless gas-fired infrared emitter emitting medium and far infrared radiation energy was used to perform the dry-blanching. Each 12.7 mm apple cube was blanched with both infrared and steam at various temperatures and time lengths. The heating rates of the samples were measured under different treatments. The product quality indicators including color, texture, total phenols, and residual peroxidase activity were measured right after blanching. The blanched products were also frozen and stored at -18° C. Then, the quality indicators were measured again after the samples were thawed at ambient temperature. Our results showed that IDB could effectively inactivate enzymes of apple cubes with high energy efficiency. It took about 5.5 min to completely inactivate the peroxidase in the samples by using IDB. Samples treated by using IDB had brighter color and firmer texture than steam blanching. Since the IDB technology can satisfactorily inactivate the enzymes with high energy efficiency and product quality, it has a great potential as an alternative to replace current steam, water and/or microwave blanching methods.
36E-86
Quality evaluation and shelf-life extension of hardy kiwifruit (Actinidia arguta ‘Ananasnaya’)
C. L. FISK1, A. M. Silver2, M. R. McDaniel1, B. C. Strik3, and Y. Zhao1. (1) Dept. of Food Science & Technology, Oregon State Univ., 100 Wiegand Hall, Corvallis, OR 97331-6602, (2) Culinary Institute of America, 1356 Monte Vista Ave., Saint Helena, CA 94574, (3) Dept. of Horticulture, Oregon State Univ., 4017 Agricultural & Life Sciences Bldg., Corvallis, OR 97331-7304
Hardy kiwifruit (Actinidia arguta) have an edible skin and are smaller in size than fuzzy kiwifruit. They are picked when physiologically mature, with ripening triggered during storage. It is not known how ºBrix at harvest affects shelf-life and quality of ripened fruit. Hardy kiwifruit are very sensitive to dehydration during storage and transport. Variable fruit quality, dehydration, and short shelf-life have been identified as the major problems related to fresh marketing. The objectives of this study were to determine the effects of harvest Brix and storage conditions on the physicochemical and sensory qualities of hardy kiwifruit and to use edible coatings to extend the shelf-life of fresh fruit. Hardy kiwifruit were harvested at 6.0, 8.7, 9.1, and 15.1 ºBrix and packaged in either high- or low-vent clamshell packaging and stored under room (22±1ºC, 45% RH) or refrigeration (2°C, 88% RH) conditions until ripe. Physicochemical properties were measured using AOAC methods and ripened fruit were processed into purees for sensory evaluation by Free-Choice Profiling method. Fruit harvested at 9.1 ºBrix were coated using a commercial coating material, SemperfreshTM, and stored at 2°C and 88% RH for up to 10 weeks for shelf-life evaluation. Results show that the use of low-vent packaging and refrigeration reduced moisture loss and lengthened the shelf-life of fresh fruit. Edible coatings provided glossiness, reduced moisture loss, and slowed ripening and surface pitting. Fruit harvested at 6.0 ºBrix were higher in sourness, astringency, and vegetal character and lower in fruity character and soluble solids than fruit harvested at later ripeness levels. Results suggest that the shelf-life of hardy kiwifruit can be extended through the use of low-vent packaging, refrigeration, and edible coatings, and support industry observation that hardy kiwifruit harvested at the same stage as fuzzy kiwifruit do not develop adequate aroma and flavor profiles for fresh marketing.
36E-88
Effect of chitosan and water soluble chitosan coatings on quality of small fruits.
J. K. NOH1, J. R. Mount1,
Edible coating has been applied on the surface of fresh produce to extend shelf-life by suppressing respiration, transmission, and microbial growth. It can help to decrease weight loss and moisture loss. It may also offer a protective barrier against bacterial contamination and spoilage. Recent studies have indicated chitosan as an effective coating that can extend shelf-life by maintaining the quality of fruits. The objective of this study was to demonstrate the effectiveness of natural biodegradable chitosan coatings in extending shelf-life and quality of fresh small fruits, such as strawberries, blueberries, and grapes. Fruits were dipped for 30 seconds in 1% chitosan in 1% aqueous acetic acid, 1% water-soluble chitosan in water, 1% acetic acid solution or tap water. Non-treated fruits served as a control treatment. Samples were stored at 4±2° C and 80±10% RH up to 24 days. Quality analysis was performed every 3 days. The analysis included measurements of texture (TA.XT plus), color (Hunter), weight loss, and ethylene and CO2 production. Statistical analysis was conducted for all dip treatments and control fruit. Ethylene production (0.038ppm/hr to 0.194ppm/hr; p<0.01) and CO2 production (3.6% to 4.7%; p<0.05) decreased significantly for both chitosan treatments compared to control fruit. Firmness among the chitosan and control treatments was also significantly different (p<0.01). Hunter b-values (p<0.01) were significantly different but there were no significant changes in L or a-values (p>0.10) among treatments. There was no significant change in moisture loss (p>0.10) among the treatments. The results suggest that chitosan coatings have a potential to be used on small fruits to maintain quality and extend shelf-life by reducing respiration.
36E-101
Processing and properties of strawberry leathers
Fruit leathers are one of the popular snacks in American diet. Strawberries are high in vitamin C and fiber. Strawberry leathers found in cookbooks are usually mixed with other fruit ingredients. Fruit leathers with strawberries as the main ingredient have not been reported. The objectives were to investigate the effects of three added ingredients on certain properties and to compare strawberry leather prototypes with commercial products. The independent variables were corn syrup (20, 30, and 40%), pectin (1, 2, and 3%), and citric acid (0.5, 1.0, and 1.5%) based on weight of strawberry natural puree. All treatments were replicated. For each treatment, the blended mixture was dried in a hot air oven at 70° C for 4.5 h until leathery sheets were obtained with thickness of 1.20 – 1.45 mm. The blends were measured for viscosity and pH while the sheets were measured for pH, water activity (aw), moisture content, color, glass transition temperature (Tg), and textural properties. All independent variables significantly affected chemical and physical properties such as viscosity profile, texture profile, tensile strength, and glass transition temperature in the order of corn syrup, pectin, and citric acid. With an aw of 0.51 and a moisture content of 9.5%, strawberry leathers are regarded as low moisture foods. The prototypes had an appealing color with moderate redness and low yellowness. Many textural characteristics were similar to two commercial fruit leathers. The results showed that each ingredient had an impact on strawberry leathers' properties. In addition, certain properties such as Tg, aw, and textural parameters were correlated with each other. Hardness, chewiness, gumminess, and tensile strength were influenced by Tg. The development of fruit leathers has the potential of adding value to fruits that are over produced or are not suitable for direct consumption and contributes to a new healthy snack.
36G-2
Effect of different additives in quality characteristics of frozen bread
J. F. VÉLEZ-RUIZ1, D. Encinas-Banda2, H. González-Loo3, M. García3, and M. E. Sosa-Morales4. (1) Dept. of Chemical and Food Engineering, Univ. de las Américas -
Dough freezing is not a simple process because baking is a complex biochemical process involved in Food Processing. The resulting bread will depend on raw materials, process conditions, and employed additives. The objective of this study was to formulate dough for bread that will be submitted to the freezing process and to get a product similar to those recently baked. Four formulations were used: (A) increasing the yeast level to 4% and adding a mixture of soybean flour and enzymes, (B) adding a mixture of gums, enzymes and gluten, (C) adding an emulsifier—diacetil tartaric of mono- and diglicerides, and adding a crioprotector agent (D). Formulations B, C, and D also included a modified starch and maintained 1.5% of yeast level. Formulations were prepared, formed, and frozen up to -12° C in a tunnel freezer at -30° C. Frozen dough was stored at -18° C for six weeks. After storage, the dough was baked at 200° C for 15 min and some quality characteristics were determined. Dough moisture content was 33.5% without changes during frozen storage, while bread moisture was 23.7% (wet basis). The specific volume ranged between 4.16 and 4.80 g/cm3, without effect of the formulation (á=0.05); these values are comparable with those reported for baguettes (4.98 g/cm3) by Bonnardel and Maitre. For texture, a compression test was carried out. The softest formulation was D with a compression of 4.68 N, while the hardest formulation was B (7.63 N). Color was affected by the additives, being the luminosity the parameter with bigger changes. A sensory analysis was conducted with 22 nontrained judges, who gave higher qualification to the formulation D, but without significant differences with respect to formulations A and C (Α=0.05).
36G-7
Rheological and textural properties of foamed dairy and nondairy emulsions prepared with various commercial hydrocolloids
A. R. TAHERIAN, A. Bégin, and E.-A. Levesque. Food Research and Development Centre, Agriculture and Agri-Food Canada, Processed Plant Products, 3600 Casavant Blvd. W., Saint-Hyacinthe, QC J2S 8E3, Canada
Commercial hydrocolloids and their mixtures are used in frozen desserts to impart texture and palatability to the final product and to protect the whipped product against excessive drainage during storage. The mechanism of stabilization by hydrocolloids in foamed emulsions is not yet fully known, and a clear understanding of their role is needed to improve functionality and extend shelf life. Contributions of maltodextrin and arabic gum to flow and dynamic properties, glass transition, particle size and distribution, water-holding capacity, and texture of nondairy emulsions, in forms of mix and frozen foam, were investigated. The results were then compared to the properties driven from a commercial ice cream mix at both mix and frozen states. An identical procedure was used to prepare foamed emulsions, and all samples were stored for one week at -20°C prior to examinations. Rheological and textural characteristics of mix and frozen were determined using an AR-1000N Rheometer equipped with a 60mm cone of 2° C and a TA-XT2 Texture Analyzer attached with a 50mm circular probe. Glass transition temperatures were also measured using a Universal V2.5H TA Instruments differential scanning colorimetry. Examination of flow and dynamic properties of prepared mixes indicated a higher viscosity and flow behavior index for the mix prepared with maltodextrin. All mixes indicated pseudoplastic behavior and G' or elastic modulus at maximum frequency level (50 rad s-1), and apparent viscosity at minimum shear rate (0.1 s-1) of mixes and texture of frozen foams were related. Glass transition temperature of mix containing matodextrin, arabic gum, and commercial ice cream mix were found to be -27.54, -30.94, and -30.41° C, respectively. The results of this study could help to understand more about the functionality of hydrocolloids in frozen desserts.
47-6
Relating sensory and instrumental measurements of cheese texture
J.-F. C. MEULLENET, Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Ave., Fayetteville, AR 72704-5585
Texture is very important to consumers' perception of cheese quality. Quality control methods, designed to evaluate texture quality, are often difficult to implement because of the challenges associated with correlating instrumental rheological measurements to perceived sensory attributes or acceptability. In addition, the texture of foods has long been recognized as a multidimensional sensory quality which manifests itself in many ways. As a result, instrumental tests should be able to predict multiple sensory characteristics to be successfully used as a quality control tool. Various aspects for developing successful and meaningful instrumental methods will be discussed, including selecting a geometry, optimizing test conditions, and utilizing novel statistical approaches. Methods such as uniaxial compression, cone penetrometry, and needle puncture will be discussed. Approaches for optimizing instrumental test conditions, including strain levels and rates, will be taken as examples and how multivariate statistical techniques can best be utilized to improve the prediction ability of rheological methods. Texture is difficult to assess from a perceptual standpoint because the physical properties of food cause complex sensations in the mouth. The selection of teeth; amount of saliva; tactile response perceived by the tongue, cheek, and lips; muscle activity; and the chewing phase are all parameters involved in the mastication of food. The lack of understanding of physiological processes has probably contributed to the inability to fully unravel texture perception. This presentation will also address some of the biomechanical aspects of texture perception. In particular, ways of incorporating learning from jaw movement studies of mastication and biting into the development of rheological methods will be explored. Finally, exploratory work in mathematical simulations of food deformation during biting and how it could be used in the future to study the effect of cheese formulation on the perception of texture will be discussed.
50-3
Multidisciplinary approaches for early determination of gelation properties of fish proteins
N. T. N. KOK1, J. D. Park, T. M. Lin, and J. W. Park. (1) Dept. of Food Science & Technology, Oregon State Univ., OSU Seafood Research Lab., 2001 Marine Dr., Rm. 253, Astoria, OR 97103-3420
Rheological properties are measured by instruments to determine product texture. Torsion, a fundamental test, and punch, an empirical test, are the most common rheological methods used to evaluate texture. For the torsion test, gel strength is represented by shear stress, whereas for the punch test, gel strength is represented by breaking force. Typically, the gels are first cooked in a 90° C water bath for 15 to 40 min and then stored overnight at 4° C. Results of the texture analysis are obtained 24 hr after sampling and usually after the product has been completed and/or shipped to market. It would therefore be beneficial to the industry to find more timely means of determining product textural quality. Our objectives were to determine the quality of fish proteins at an early stage of production using differential scanning calorimetry, oscillatory dynamic properties, and biochemical properties, and to establish a relationship between these three methods and fracture gel analysis. Strong correlation for deformation against ATPase activity was found with R2=0.74. Deformation increased with an increase in ATPase activity. A strong correlation between the storage moduli G'1 against deformation, with a correlation coefficient of (R2) 0.74, was established. The correlation coefficient of G'1 against breaking force was 0.55. The correlation coefficient of G' initial peak-G'2 against deformation was 0.63 and for breaking force 0.55. G'1 and G initial peak-G'2 decreased with increasing breaking force and deformation. Early determination of fish protein quality was determined by ATPase activity and the dynamic oscillatory method. These methods could be incorporated into industry to obtain timely and accurate results pertaining to the gel quality of the fish proteins being processed.
50-12
Incorporation of minced trout (Oncorhynchus mykiss) in egg based noodles
D. SCOTT, Food Science and Human Nutrition, Washington State Univ.,
Improving recovery of muscle tissue increases utilization of aquatic food products. Development of novel, yet feasible applications, for minced fish recovered from fish frames is needed. Noodles products containing fish or shrimp muscle or flavorings are widely consumed, particularly in Asian markets. The objective of this study was to determine the feasibility of incorporating washed minced trout muscle into egg based noodles and evaluating functional, textural and sensory attributes. A conventional egg noodle recipe was modified to replace 10% or 20% of the flour with minced trout by weight. Fresh noodles were tested for color and moisture content, then either boiled or fried. Moisture, texture profile analysis (TPA) parameters, color, and yield were determined. A consumer panel evaluated acceptability and preference. Moisture content of the fresh noodles increased with increasing fish content. The color of fresh noodles containing fish was redder and more yellow than the control. There was no significant difference in cooking loss, cohesiveness and springiness among any of the treatments. There was a significant decrease in hardness, gumminess, and chewiness in the cooked noodles as the level of minced fish increased. For the fried noodles, there was no significant difference in texture, moisture content, and yellow color as a function of substitution level. However, the fish noodles were darker and redder than the controls. Panelists found the control and experimental products to be equally acceptable, except for those panelists who did not like fish. Preference was evenly divided between the control and experimental products. These findings indicate the feasibility of incorporating minced fish into egg noodle products. Developing new uses for minced fish will increase utilization and the saleable of currently low grade minced products.
52-3
Effect of structure and phase behavior on physical markers for crispness
H. DOGAN, L. Samuel, and J. L. Kokini. Dept. of Food Science, Rutgers, The
Crispness is a key textural attribute of expanded cereal products greatly affecting consumer acceptability. Structure-texture-sensory relationships are of immense value in designing new products of desired properties in the food industry. We attempted to identify appropriate sensory perception cues for crispness and to systematically study the effect of cellular structure, phase behavior and mechanical deformation of expanded products on crispness sensation. Corn extrudates of diverse structures were produced by extrusion at 120-140°C, 15-20% of feed moisture content and 200 rpm screw speed. Sodium bicarbonate was added at 0.5-2% levels to alter the cellularity and cell wall characteristics. Structural characterization of extrudates was done in terms of cell size and cell size distribution, cell wall thickness, solid density, bulk density and porosity. Mechanical properties were determined by uniaxial compression at 1 mm/sec and 80% strain level. The jaggedness of the resulting force deformation curves were evaluated by calculating the number of peaks, ratio of linear distance and fractal dimensions. The method of magnitude estimation was used for sensory evaluation of these products, for crispness and hardness. Addition of sodium bicarbonate increased cell density but decreased average cell size. Average number of peaks was found to be a good predictor for sensory crispness and also related well with the structural characteristics of extruded corn. Experimental data clearly showed the impact of structural properties on instrumental and sensory texture. Fractal dimension excessively compressed the jaggedness of the force deformation curve for sensory evaluation purposes. Both sensory and instrumental crispness were highest in the glassy state and decreased significantly as the samples underwent a phase transition to the rubbery state at higher water activities. Identification of the appropriate sensory perception cues is of critical importance to relate instrumental textural parameters to sensory properties.
53-4
Effect of crumb density, glycerol, and enzyme addition on bread staling
G. KALETUNÇ, Dept. of Food, Agricultural and Biological Engineering, The Ohio State Univ., 590 Woody Hayes Dr., 210 Agricultural Engineering Bldg., Columbus, OH 43210-1058 and A. H. Barrett, U.S. Army Natick Soldier Center, U.S. Army Research, Development and Engineering Command, Combat Feeding Innovative Science Team, Kansas St., Bldg. 36, Rm. E-108, Natick, MA 01760-5018.
Parameters that increase the shelf life of bread by slowing the staling process are beneficial to bread manufacturers. The analysis of the effect of baking protocols and formulation on staling must be characterized in order to determine and control the critical parameters, thereby improving textural shelf life of bread. The objective of this study was to determine the effect of increased crumb density of white pan bread on the rate of staling. The effects of glycerol, protease, and amylase enzymes, and a modified bake process were studied. A method restricting the rise of the bread to increase the crumb density was developed. Densities of control bread crumb and high-density bread crumb were 0.29 to 0.34 and 0.36 to 0.41 g/cm3, respectively. Loaves of both high-density and control bread were vacuum-packaged and held for ten wk in an incubator at 23° C. The effect of formulation and the baking protocol on starch crystallization and texture of bread were monitored through DSC and texture analysis. DSC was used to monitor melting endotherms of recrystallized starch, while compression studies were employed to quantify the elastic modulus at 0, 1, 2, 4, 8, and 10 wk. Water activity for the breads with and without glycerol was 0.83 to 0.88 and 0.90, respectively. DSC analysis showed three irreversible endotherms occuring at approximately 66° C, 99° C, and 138° C. The endotherms at 99° C and 138° C were interpreted as melting of amylose-lipid complex and uncooked starch, respectively. The 66° C endotherm was attributed to be the melting of amylopectin recrystallized during storage and increased during storage. Bread firmness was evaluated in terms of the elastic modulus increased with crumb density without apparent relation to starch crystallization. The modified bake process that was used to create higher-density bread may have decreased crystal formation and crumb firming, thereby improving the textural characteristics and shelf life of bread.
53-8
Physical properties of muffins as affected by peanut flour and dried plum powder
M. J. HINDS, Dept. of Nutritional Sciences, Oklahoma State Univ., 309 HES Bldg., Stillwater, OK 74078-6141, T. J. Bowser, Biosystems and Ag Engineering, Oklahoma State Univ., and S. S. Reilly, Oklahoma Food and Agricultural Products Research and Technology Ctr., Oklahoma State Univ., 105 FAPC, Stillwater, OK 74078-6055.
Peanuts and dried plums contain components that can improve cardiovascular and bone health, respectively. Muffins can serve as convenient deliverers of these functional ingredients. The objective of this study was to evaluate the physical properties of muffins as affected by peanut flour (12% fat, PF), dried plum powder (PLMP), and appropriate additives. Response surface methodology was used with a Box-Behnken 3-level fractional factorial design in a standard muffin formulation. The four independent variables were: PF (50, 75, 100% wheat flour replacement); PLMP (6, 15, 24% dry ingredients wt); calcium-stearoyl lactylate (CSL, 1.5, 2.0, 2.5% dry ingredients wt); and glycerol monostearate (GMS, 0.5, 1.0, 1.5% dry ingredients wt). Their effects on texture profile (TA.XT2i Texture Analyzer), water activity, and crumb structure by computer microtomography (Scanco Micro-CT 40) were evaluated. PLMP affected all physical properties, but PF did not affect water activity of the muffins, which decreased with increased PLMP. CSL and GMS both affected muffin resilience, but CSL only affected hardness and chewiness, whereas GMS had significant effect on crumb cohesiveness. PF and PLMP had a synergistic effect on hardness, which peaked in formulations containing 100% PF and 24% PLMP for all levels of CSL. When formulations contained 1% GMS and 1.5% CSL, chewiness and gumminess increased with increased PF only, but for all other combinations of GMS and CSL, chewiness and gumminess increased with increased PF and PLMP. Springiness decreased with increased PLMP for all levels of GMS and CSL, but increased with high levels of PF when CSL was > 2% and GMS was > 1%. Generally, cohesiveness and resilience increased with higher PF and decreased with higher PLMP. Crumb cells were larger and more uniform with decreased PLMP and with increased CSL. Muffins containing 75 to 85% PF, 18 to 24% PLMP, 1.5% CSL, and 0.5 to 1.0% GMS would have optimum physical properties.
53-11
Utilization of mushroom sclerotium in traditional Chinese plain noodles
K. M. MA, Dept. of Biology, The Chinese Univ. of Hong Kong, Room 381, Science Center South Block, Shatin, New Territories, Hong Kong, China and P. C. K. Cheung, Food and Nutritional Sciences Programme, The Chinese Univ. of Hong Kong, Shatin, New Territories, Hong Kong, China.
Sclerotium is the dormant state of mushrooms, which contains over 80% dry weight of nondigestible carbohydrates. It could be a potential source to fortify the dietary fiber content in various kinds of functional foods. The objective of this project was to evaluate the nutritional and sensory attributes by incorporating three different kinds of mushroom sclerotia into the traditional Chinese plain noodles. Three edible mushroom sclerotium powders produced from Poria cocos (PC), Polyporous rhinoceros (PR), and Pleurotus tuberregium (PTR) were characterized for their functional properties. They were used to substitute for high-gluten flour at three levels (3, 6, and 10% w/w) based on the original Chinese plain noodle recipe. TA-TX2 texture analyzer was used to analyze the noodle texture. The sensory attributes of the noodles with 10% (w/w) sclerotium were evaluated in comparison with the control noodles using hedonic scale for color, surface smoothness, flavor, aftertaste, stickiness, springiness, and total acceptance. Sclerotium of PTR had a significantly lower water-holding capacity (P < 0.05) than PC and PR sclerotia. This resulted in a significantly greater cooking loss in the PTR-substituted noodles when compared to the PC- and PR-incorporated noodles at all levels of substitution. The hardness, stickiness, and firmness of the noodles differed with increasing levels of various sclerotium substitutions. The total dietary fiber content in 10% sclerotial PC-, PR-, and PTR-substituted noodles are 8.09% ± 0.65, 8.64% ± 0.82, and 6.60% ± 0.46, respectively. There were no significant differences in starch, protein, fat, and ash content among 10% sclerotium-containing noodles (P > 0.05). Sensory panelists did not show any significant difference in the preference to any of the noodles. However, the PC- and PR-containing noodles have a significantly higher total acceptance than the PTR-containing noodles. Mushroom sclerotia from Poria cocos and Polyporous rhinoceros are potential ingredients to be incorporated into fiber-rich food.
54C-2
Gel formation and characteristics of flaxseed gum
Flaxseed gum is one of hydrocolloids. Recent studies suggest that the flaxseed gum displays weak-gel properties that can be used to replace most of the non-gelling gum for food and non-food system applications. However the weak-gel properties of flaxseed gum have not been studied in detail. The aim of this work was to study the mechanism of gel formation and examine the effect of different factors, including dissolution temperature, concentration, pH level and different valent cations, on the gel strength. Both of Dynamic Rheological Measurement and Differential Scanning Calorimetry were used to determine gelling and melting point of flaxseed gum. The gel-formation mechanism of flaxseed gum was described using Atomic Force Microscopy and chemical methods. The gel strength and microstructure were measured with Texture Analyzer, Scanning Electron Microscopy and Zeta Potential Measurement. The results showed that both gelling and melting point increased with increase in dissolution temperature. But the gelling point was lower than its melting point at the same dissolution temperature due to extra energy for transition from order to disorder. The proposed mechanism of gelation was that the hydrogen bonds between hydroxyl groups of flaxseed gum molecules played a primary role. The maximum gel strength was obtained at pH 6 to 8, the gel strength decreased with lowering pH values at pH 2 to 6 or raising pH values above pH 8. Addition of Na+ lowered the Zeta potential, thus decreasing the gel strength. Addition of divalent cation Ca2+ had an unusual effect on the gel strength. Low concentration of CaCl2 (<0.3%w/w) increased the gel strength with facilitating the formation of three-dimensional networks due to Ca2+ cross-linking; but high concentration of CaCl2 (>0.3% w/w) decreased gel strength with decreasing Zeta potential. The flaxseed gum could form thermoreversible cold set gel, therefore it can be widely applied in meat and pasta products.
54D-6
Water vapor permeability and mechanical properties of whey protein based films
O. ERDOHAN and K. N. Turhan. Department of Food Engineering,
The edible films and coatings improve food quality, extend shelf life, append to foods some functional properties and reduce using of synthetic packaging materials. Some ingredients such as many proteins, polysaccharides, and lipids have good film forming properties. It is possible to improve film characteristics for specific application by incorporating these film forming ingredients. The objective of this study was to investigate the effect of different combinations of whey protein powders and methylcellulose (MC) on film formation and physical properties of films. Films were prepared from 5 % (w/v) whey protein isolate or concentrate, MC (30, 40, 60, 65, 70, 80 %, MC/whey protein powder), and glycerol as a plasticizer (50 %, glycerol/total polymer, w/w). ASTM E96-80 was used to determine gravimetrically water vapor permeability of the films. A texture analyzer was used to determine mechanical properties of whey protein based films according to ASTM D638M-93. Addition of MC to whey protein based film caused a decrease on water vapor permeability (WVP) of films. The lowest WVP values were obtained with 80 % MC/whey protein powder films. Tensile strength and elongation increased as MC amount in film forming solution increased. There is the potential to improve the physical properties of whey protein films by incorporating MC into the film system. Future work in this area should be improve permeability and mechanical properties of whey protein powder-MC films using different lipids and plasticizers.
54D-11
Development of cranberry pomace based edible films
Cranberry pomaces, byproduct from fruit juice and concentrate processing, are rich in natural pigments, phenolic antioxidants, organic acids, proteins, cellulose and pectin. Unfortunately, this useful resource hasn't been well utilized. The cellulose, pectin, and natural pigment in cranberry pomace are important components for making edible films. The development of fruit pomace based films would add significant value to the fruit processing industry. The objectives of this study were to examine the feasibility of using cranberry pomace extract to make edible films containing natural cranberry pigments and flavor, and to evaluate the mechanical and barrier properties of the films. Frozen cranberry pomace was grinded and mixed with water at ratio of 1 to 5. Hot water extraction was performed at 75 oC for 30 min. Pectin, protein, fat, ash, and moisture contents of grinded cranberry pomace and water extracts were analyzed. Low methoxyl pectin (LMP) or high methoxyl pectin (HMP) at concentration of 0.25% to 0.75% was added into the extracts for making films. Sorbitol or glycerol (0.25%) was used as a plasticizer. The pH and Brixo of film forming solutions and barrier and mechanical properties of dried films were analyzed. About 1.25% solids were obtained from cranberry pomace water extracts. Dried films contained bright red color and natural cranberry flavor. The type and concentration of pectins and plasticizers affected film properties. Tensile strength of the films increased with pectin addition. Generally, LMP added films showed higher tensile strength and lower water vapor permeability than those HMP added films. This study demonstrated the potential of developing cranberry pomace based edible films that have natural color and flavor. Such colorful films may be used as a stand alone films or edible coatings for various food products.
54D-17
Antimicrobial films as a potential technology to increase pathogen radiation sensitivity
J. HAN, M. E. Castell-Perez, and R. G. Moreira. Dept. of Biological & Agricultural Engineering, Texas A&M Univ.,
Electron beam irradiation is becoming a well-established decontamination technology. However, it is limited by undesirable changes in product quality at the required radiation doses. Thus, if we can increase the radiation sensitivity of the pathogens, we may successfully reduce these quality changes. One approach is to use packaging materials with self-sterilizing ability that may reduce the needed irradiation dose. Our first goal was to establish whether low-dose irradiation treatments affected the properties of antimicrobial films. FDA-approved sorbic acid, carvacrol, cinnamaldehyde, thymol and rosemary oleoresin, were added to a polyamide solution (1% of final solution weight). The coatings were applied to one side of low-density polyethylene (LDPE) films, dried at 20° C for 12hr, irradiated (1-3kGy) using a 10MeV linear electron accelerator, and stored in a desiccator until analyzed. We evaluated the antimicrobial effectiveness of the films against L. innocua ATCC 33090, and E. coli ATCC 11229 and ATCC 884 using agar diffusion and liquid culture tests. The films mechanical and barrier properties were measured using standard methods. All films showed inhibition zones in agar diffusion test against L. innocua and E. coli ATCC 884. However, films with carvacrol, cinnamaldehyde, and thymol extract did not show inhibition zone against E. coli ATCC 11229. In the liquid culture test, the active compounds significantly reduced the specific growth rate and final cell concentration of L. innocua. Irradiation dose did not affect the antimicrobial activity of the compounds. Neither the presence of active compound nor irradiation dose affected the mechanical (percent elongation, toughness, tensile strength) and barrier (water vapor, oxygen permeability) properties of the films. Polyamide coating, however, significantly reduced their tensile strength. Film surface properties will be investigated. These results are an encouraging first step to the development of self-sterile active packaging systems for food safety applications.
54E-11
Flavor and texture characterization of Mexican Fresco cheese by sensory evaluation and instrumental analysis
B. VALLEJO-CORDOBA1, M. D. J. Torres-Llánez2, A. F. González-Córdova2, and M. D. C. Estrada-Montoya2. (1) Dept. de Tecnología de Alimentos de Origen Animal, Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Carretera a La Victoria Km 0.6, Apartado 1735, Hermosillo, Sonora, 83000, Mexico, (2) Mexico
Fresco cheese or Queso Fresco made from pasteurized milk as required by the Mexican regulations, results in a uniform product of good sanitary quality; however, pasteurization adversely affects cheese flavor and texture. The indigenous microflora in the raw milk are partly responsible for the development of the typical flavor and texture of the traditional artisanal cheese preferred by the consumer. Thus, to restore flavor and texture, nonspecific starters isolated from artisanal cheese made from raw milk were developed to improve these attributes. Although these cheeses were found to have acceptable sensory attributes, their flavor and texture were not fully characterized. Thus, the objectives of this work were to fully characterize the flavor and texture of Queso Fresco by using sensory evaluation and instrumental analysis and to monitor proteolysis and lipolysis during refrigerated storage. Three batches of Queso Fresco were prepared. Cheeses were made by pasteurizing milk and using five different specific starters. Flavor and texture attributes were evaluated by sensory analysis and instrumental analysis. Volatiles were determined by gas chromatography, and texture was evaluated by a texture analyzer. Proteolysis was monitored by determining the nitrogen content of fractions that are soluble in water (WSN), trichloroacetic acid (TCA), and phosphotungstic acid (PTA). Lipolysis was monitored by determining the acid degree value (ADV). Sensory analysis and nonprotein nitrogen indicated that Queso Fresco made with one of the specific starter cultures was not significantly different (P > 0.01) from the traditional artisanal cheese (control). However, ADV values, gas chromatographic profiles and firmness for this cheese were signficantly different (P < 0.01) from the control. The flavor and texture characterization of Fresco cheese presented in this work provides the basic information needed to establish standards of identity required by the Mexican regulations.
54E-24
Textural attribute of yogurt manufactured from milk treated with microbial transglutaminase
M. G. Vera-Vite, Departamento de Tecnología de Alimentos de Origen Animal, Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Carretera a la Victoria Km 0.6, Apartado 1735, Hermosillo, Sonora., 83000, Mexico, A. F. GONZÁLEZ-CÓRDOVA, Centro de Investigación en Alimentación y Desarrollo (CIAD), Mexico, and B. Vallejo-Cordoba, Mexico.
The texture of yogurt is highly dependent on the amount and functionality of the individual components comprising yogurt gel, and on the interaction between the components as well as on the technological steps in the production process. Milk composition and process influence yogurt stability (wheying-off) and rheological properties such as firmness, consistency, adhesiveness, and cohesiveness. To improve texture and prevent syneresis, stabilizers and polysacharide-producing cultures have been used. As an alternative method to improve texture, chemically induced acid gels were produced after milk enzymatic modification with microbial transglutaminase (MTGase). MTGase is an enzyme that catalyzes the cross-linking of proteins through the formation of covalent bonds. The two amino acids that it uses to cross-link are glutamine and lysine. The objective was to evaluate the texture of yogurt made from MTGase-treated milk and to compare it to the yogurt made from untreated milk. Milk was batch-pasteurized at 85 °C for 30 min, cooled to 50 ºC, and treated with varying amounts of MTGase (0.03, 0.09, and 0.15%). Then it was inoculated using a yogurt starter culture (S. thermophilus and L. delbrueckii sbs. bulgaricus). After inoculation, samples were incubated at 43 ºC until a pH of 4.4 was reached. Additionally, yogurt was made from milk supplemented with 3% nonfat dry milk (NFDM). Wheying-off, pH, firmness, consistency, adhesiveness, and cohesiveness were monitored after 24 hr of refrigerated storage. Yogurt made from milk treated with MTGase (0.15%) developed less wheying-off, higher firmness, consistency, adhesiveness, and cohesiveness than the control made from untreated milk or yogurt made from milk supplemented with 3% NFDM (P < 0.05). Milk treatment with MTGase proved to be a good alternative method to improve yogurt texture and may reduce or eliminate the use of stabilizers or the fortification with NFDM.
54F-21
Effect of electron beam irradiation on quality of blueberries (Vaccinium corymbosum L)
M. A. MORENO, C. Gomes, P. C. F. Da Silva, M. E. Castell-Perez, and R. G. Moreira. Dept. of Biological and Agricultural Engineering, Texas A&M Univ.,
Blueberries have become a product of interest in the
54F-23
High pressure homogenization for fresh cheese manufacturing
F. SAN MARTIN1, F.
Consumers demand for fresh-like products impose challenges for food processors. In some countries, fresh cheeses are still made with raw milk, thus posing a health risk for consumers. Technologies other than thermal treatment are being investigated for decreasing microbial population in milk while retaining cheese-making properties.
The objective of this study was to evaluate the effect of high pressure homogenization (HPH) on the native microflora of milk and on wet yield of fresh cheese, and to compare the effects against low temperature-long time (LTLT) pasteurized milk.
Raw milk from a local dairy farm was either homogenized at 100MPa (0-4 times), for holding times at treatment pressure equivalent to 0, 15, 30, 45 and 60 s or pasteurized at 63oC for 30min. Samples from each treatment were serially diluted in 0.1% peptone water. Pour plate method was used to determine aerobic mesophiles and coliforms. Fresh cheeses were made according to a standard procedure. Wet yield was determined as the amount of cheese obtained per 100 kg of milk.
Results show that coliforms and aerobic mesophiles in milk decreased with increasing holding times. Holding times of 60s reduced 3.6 log cycles of aerobic mesophiles and 3.7 log cycles of coliforms and resulted in milk with microbial populations comparable to LTLT pasteurized milk (3.4 and 3.0 log cycles in aerobic mesophiles and coliforms respectively). Wet cheese yield for raw milk cheese was 16.3% whereas HPH milk at residence time 60s resulted in significantly higher wet yield 19.6%. No significant difference in yield was observed between raw, pasteurized, 15, 30 or 45s.
Homogenization of milk by high pressure resulted in microbial inactivation comparable to LTLT pasteurization while increasing cheese yield, therefore HPH constitutes a feasible alternative for reducing microbiological risks in fresh cheese.
54G-26
Isolation and characterization of antimicrobial and antioxidant agents from Lippia graveolens and their application in edible films.
S. Mendoza1,
In order to find alternative ways to preserve food while satisfying the increasing consumer demand for safe, all-natural products, some research has been devoted to the identification of plant-based antimicrobials and anti-oxidants. Among the “oregano” plants, characterized by a high carvacrol content, is Lippia graveolens (Mexican oregano). The aerial parts of the plant are used as a condiment as well as antiseptic, antipyretic, analgesic, abortive, antispasmodic, anti-inflammatory agent, and for the treatment of menstrual disorders and diabetes. This plant was examined as potential source of water-soluble antimicrobial and antioxidant compounds with the framework of research projects for the development of preparations containing natural bioactive secondary metabolites. The methanolic extract of L. graveolens, without the presence of the essential oil components, showed significant activity against Staphylococcus aureus, Listeria monocytogenes and Salmonella sp. In addition, the extract showed a dose-dependent antiradical activity, with an IC50=170.3 ± 1.11 µg/ml. To identify the bioactive compounds, the methanolic extract was parti-tioned with n-BuOH and water, each extract was croma-tographed through Sephadex LH-20, the antimicrobial and antioxidant activities of the resulting fractions were evaluated. The most active fractions were separated by RP-HPLC. After purification, the chemical structure of the bioactive compounds was determined. To evaluate the potential use of the extract as a food additive, it was incorporated to a soy protein film. These results suggest that the extracts and pure compounds from L. graveolens, might be used as an alternative of natural preservatives.
54H-3
Quality of retail packaged whole egg powder during long-term storage
Shelf life studies on whole egg powder (WEP) usually extend for no more than one year, which is the generally accepted shelf life of this commodity. However, egg products are available in the retail market packaged as long-term food storage items for emergency use. Further research is needed to determine the effects of long-term storage on the quality of WEP.
The objective of this research was to investigate the quality of retail packaged WEP held at ambient temperatures up to 32 years.
Twenty samples of WEP packaged in No. 10 cans were obtained from donors. Samples ranged in age from 2 months to 32 years. A 52-member consumer panel evaluated reconstituted scrambled WEP for appearance, aroma, and overall acceptability using a 9-point hedonic scale. Acceptance for use in everyday and emergency situations was also determined. Analyses included can headspace oxygen, headspace hexanal, water activity and color.
Headspace oxygen for most samples was <0.5% but five samples ranged from 11.2 to 20.8%. Headspace hexanal ranged from 2.3 to 8.9 ìg/g for samples with <0.5% headspace oxygen and from 38.4 to 98.0 ìg/g for the other five samples. Water activity ranged from 0.13 to 0.41. Hunter L* values ranged from 77.4 to 88.0. Hedonic scores for appearance, aroma and overall acceptability for the 2 month old sample were significantly higher than scores for all other samples. Acceptance for everyday use ranged from 4 to 89% with the majority of samples having less than 25% acceptance. For emergency use, the 2 month sample had 97% acceptance and the other samples ranged from 52 to 89%.
Results indicate that WEP is not capable of retaining a high percentage of consumer acceptance during extended storage and should not be recommended for long-term food storage purposes.
54H-15
Use of irradiation as a HACCP, CCP step for bulk soybeans: Influence on microbial load, functional properties, and yield of soymilk and tofu
L. A. WILSON, Dept. of Food Science & Human Nutrition, Iowa State Univ., 2541 Food Science Bldg., Ames, IA 50011-1061, M. H. Perchonok, National Space Biomedical Research Instititute, NASA-Johnson Space Center, 2101 NASA Rd. 1, Mail Code SF3, Houston, TX 77058, and S. J. French, Lockheed Martin Space Operations Co., Lockheed Martin Corp., 2101 NASA Rd. 1, Mail Code SF3, Houston, TX 77058.
Soybeans are stored, and shipped around the world for their use in food and feed. NASA selected soybeans for lunar and planetary missions, where they may be shipped in bulk. The presence of food-borne and/or pathogenic microorganisms on bulk agricultural commodities is of concern to NASA and Homeland Security. Irradiating soybeans during bulk storage prior to shipping could provide microbial safety, but potential germination, sensory, and functional property changes due to oxidation might make the soybeans unsuitable.
The objective of this study was to determine the influence of e-beam and gamma radiation (pasteurization and sterilization) on whole soybean microbial load, germination rate, ease of processing, and soymilk and tofu quality.
2003 Vinton 81 (industry standard), IA 2032LS (lipoxygenase-free), and Proto (high antioxidant potential) soybeans were packaged and irradiated (0, 10, 20 kGy) by e-beam or gamma rays. Soybeans were evaluated for peroxide value, thiobarbartic acid, hexanal, antioxidant potential (PhotoChem)], microbial load (SPC, coliforms, Salmonella, yeasts, molds), germination, and their ability to produce soymilk and tofu. Soymilk and tofu were produced using the standardized Japanese process, and calcium sulfate dihydrate. Yields of soymilk, tofu, okara, and whey along with color, texture, and aroma of the soymilk and tofu were determined instrumentally.
Irradiation of whole dry soybeans using e-beam or gamma rays at 10 or 30 kGy provided microbial safety. However, these doses caused oxidative changes that resulted in soybeans with higher TBARS and hexanal, soymilk and tofu with rancid aromas, high hexanal levels, dark color, lower tofu yields, more paste-like okara, and loss of seed germination. Lower doses may reduce these problems, but the ability to insure microbial safety of bulk soybeans may be lost.
A No Effect Dose for food quality, below 10 kGy, with an effective kill step dose (CCP) for food-borne illness microorganisms needs further investigation.
54H-21
Textural properties of commercial wheat flour tortillas during storage
H. AKDOGAN1, O. K. Chung1, H. Singh2, and G. Lookhart1. (1) Grain Marketing and Production Research Center, USDA, ARS, 1515 College Avenue, Manhattan, KS 66502, (2) School of Kinesiology and Nutritional Science, California State University, 5151 State Univ. Dr., Los Angeles, CA 90032
The tortilla industry is the fastest growing segment of the baking industry. In the
The purpose of this study was to evaluate the shelf-life of commercial wheat flour tortillas through their textural parameters.
Three types of tortillas (regular, 98% fat-free, and whole wheat) of two different commercial brands (Brand A and Brand B) were studied. All samples were subjected to extensibility and stress relaxation tests by using a TA-XT2 Texture Analyzer at days 0, 2, 6, 9, 12, 15, 19, 23, and 33 of storage. One-way analysis of variance (ANOVA) was used to analyze the data. Fisher's least significant difference (LSD) at á=0.05 were used to identify the significant differences in the means of measured and calculated textural parameters.
The gradient (modulus of deformation) and work (area under the curve up to maximum force to tear) were not indicative of the textural changes of the studied tortillas. The calculated parameters from the stress relaxation (SR) curve, k1, k2, and % SR, and the distance to tear from the extensibility measurements were able to identify either the first days of storage (day 0 and/or 2) or the last days of storage (day 23 and/or 33). The significant changes came shortly after opening their packages for both brands of regular tortillas. Detectable changes for 98% fat-free tortillas of Brand A and B came after 23 and 2 days of storage, respectively. For whole wheat tortillas most results were not conclusive.
The calculated textural parameters, k1, k2, % SR , and distance to tear, identified the significant differences among days of storage. Further research on tortilla formulation and ingredient functionality may provide a better understanding on tortilla staling.
71A-20
Flow and physico-chemical properties of some custard model systems formulated with skim and whole milk
J. F. VÉLEZ-RUIZ, Chemical and Food Engineering, Universidad de las Américas -
Custards, or “natillas,” a semisolid dairy dessert of wide consumption in some countries, is increasing its importance in
71A-32
Texture and microstructure of low-fat set yogurt containing starch
S. Rattanasuwan and W. TUNGJAROENCHAI. Faculty of Agricultural Industry, King Mongkut's
Addition of milk solids is a routine method to improve the texture of milk products. Inclusion of wheat starch has been used to improve the texture of yogurt, which resulted in an increased consistency of product with cleaner flavor and cereal notes. Research work on using tropical starch such as tapioca, waxy maize, and waxy rice starch in yogurt is limited. Our objective was to investigate the effects of modified tapioca, waxy maize, and waxy rice starch on texture, syneresis, whey holding capacity (WHC), microstructure, and sensory quality of low-fat set yogurt. Low-fat set yogurt was made by using a commercial DVS freeze-dried culture (YC 830). Modified tapioca (MTS), waxy maize (WMS), or waxy rice starch (WRS) was included in levels of 0, 0.5, 1.0, and 2.0% (w/w). Incubation was done at a temperature range of 42 to 45 °C for 6 hr. A TA.XT2 texture analyzer was used to evaluate texture of yogurt. Syneresis and WHC of yogurt were determined by the drain and centrifugation methods. Microstructure was viewed under scanning electron microscope (SEM). Twenty panelists performed preference test with 7 Hedonic scales. MTS increased the firmness of yogurt greater than those of WMR or WRS. WRS had the least effect on the firmness quality. Starch increased WHC and decreased syneresis of the curd. Scanning electron micrographs (SEM) suggested that starch granules helped stabilization of casein network. Yogurt containing 1.0% MTS and 2.0% WRS received the highest flavor scores. WMS and MTS imparted a poor taste quality in yogurt. WRS at 2.0% was recommended for low-fat set yogurt with a cleaner flavor. Starch could be used to improve or modify texture of yogurt. Starch stabilizers could help correct the problem of cooked flavor by excessive use of skim milk powder.
71B-4
Transglutaminase effects on gelation capacity of thermally induced turkey protein gels
M. L. DONDERO1, R. D. Burboa, V. A. Figueroa, and E. A. Curotto. (1) Escuela de Alimentos, Pontificia Universidad Católica de Valparaiso, Casilla 4059,
Transglutaminase (TG) is an enzyme that catalyzes an acyl-transfer reaction between primary amines and the gamma-carboxyamide group of peptide or protein-bound glutaminyl residues. TG action over protein molecules, causes a cross-linking and polymerizing effect of these latter, through epsylon-(gamma-glutamyl)lysine bonds. This cross-linking originates drastic physical changes in protein-rich foods. The objective of this work was to evaluate the microbial transglutaminase effects (MTGase)on turkey gels texture. Time and incubation temperature, enzyme concentration and Chilean jack mackerel (Trachurus murphyi) addition effects, were studied. The quality of turkey gels was assessed by measuring their breaking force, deformation and gel strength. Additionally, Proteolytic activity, SDS-PAGE electrophoresis and epsylon-(gamma-glutamyl)lysine bonds by HPLC were carried out on the gels. MTGase addition, significantly increased gel strength. The optimal attributes were observed at 60 °C after 2h and addition of 0.5% of MTGase, with a gel strength 110% higher than the control-gel. Jack mackerel surimi and MTGase incorporation into turkey-gels, significantly increased gel strength. A mix of 75% surimi/25% turkey and 0.5% MTGase, at 25° C and 60° C, increased gel strength up to 416% and 336%, respectively. SDS-PAGE analysis revealed that the myosin heavy chain (MHC)content decreased and that the cross-linked protein amount, apparently increased as a function of incubation time and MTGase concentration. Proteolysis was also observed. The production of epsylon-(gamma-glutamyl) lysine bonds also increased as a function of MTGase concentration and incubation time . These results suggest that is possible to improve mechanical properties of turkey gels by adding jack mackerel surimi and MTGase, thus increasing their potential utilization in minced based-products.
71B-27
Effect of UV irradiation on tensile strength and anti-Listeria, anti-Salmonella and anti-E. coli O157:H7 activities malic/lactic acid incorporated soy protein films
Edible films should have adequate mechanical strength, flexibility and extensibility for a coating application to maintain integrity of the product and withstand external stress. UV−irradiation (UV−I) has been reported to increase tensile strength and darkness of soy protein film at alkaline pHs. Antimicrobial-incorporated films have their activity mostly at acidic pHs at which the film tensile strength is low. Effect of UV−I at different steps of film preparation on the tensile strength of films produced at acidic pHs need to be studied to increase the efficiency of UV−I with low dosage. The objective of this study are to evaluate the effectiveness of UV−I at different steps of film preparation on the mechanical strength and anti−Listeria, anti−Salmonella, and anti−E. coli O157:H7 activity of the films. Soy protein films were treated with UV−I irradiation (7.56 J/cm2) at pH 7.0 and 3.0. Malic and lactic acid incorporated films were treated with UV-I and the antimicrobial activity of the films were tested. UV−I of soy protein isolate and during film preparation steps before casting, before drying , and after drying (22.3 −22.8 MPa) increased tensile strength of the film at pH 7.0 compared to control without UV−I (16.6 MPa). At pH 3.0 UV−I of soy protein isolate and during film preparation before casting and before drying increased tensile strength of the film(13.3 −14.2 MPa) compared to control without UV-I (11.7 MPa). Effectiveness of UV−I was depended on the steps of treatment during film preparation. UV−I to soy protein isolate and the film solution before drying increased tensile strength of the film at pHs 3.0 and 7.0. Antimicrobial activities of the malic and lactic acid incorporated films were not affected by the UV−I. Soy protein isolate can be treated with UV−I to increase tensile strength of the film without affecting antimicrobial activity.
71C-3
Relationship between network density, and mechanical and barrier properties of zein/oleic acid films
M. K. LAU, H. Dogan, and J. L. Kokini. Dept. of Food Science, Rutgers, The
Mechanical and barrier properties of protein films are strongly related to their structural organizations. Mixing is one of the critical steps of film-making process. During mixing, different chemical entities of like charges interact, hydrophobic and hydrogen bonding takes place. The film composition, and mode and extent of mixing affect the network formation. Density of the network formed determines the functional properties of the resulting film. The objective of this research was to characterize mechanical and barrier properties of zein-oleic acid films, and relate these properties to network density through rheological measurements. Zein:oleic acid resin were prepared by dissolving zein in 75% ethanol, adding oleic acid and monoglyceride and heating the solution at 60-70° C for 10 min., and finally precipitating in cold water bath at 2° C. Zein:oleic acid doughs were developed to various extents by kneading them at different modes and times using an extruder. The mechanical history of the doughs was quantified in terms of specific mechanical energy (SEM) input. Small amplitude oscillatory and stress relaxation measurements were done to characterize the network properties of doughs. Films were subjected to tensile test for mechanical characterization. Parameters obtained were tensile strength, elongation at break and Young's modulus. Barrier properties were characterized by measuring water vapor and oxygen permeability of the films. Network structure during mixing improved by increasing mechanical energy input. High SME levels resulted in longer relaxation times, lower molecular weights between entanglements. A more uniform network implied better mechanical and barrier properties. Films had low water permeability levels due to the hydrophobic nature of zein. Films showed lower oxygen and water permeability and higher tensile strength as the molecular weight between entanglements. Clear understanding of network formation is important to optimize the film-making process, which in turn helps to control and predict functional properties of resulting films.
71D-6
Color and texture development in potato chips
F. W. PEDRESCHI, Dept. of Food Science and Technology, Univ. de Santiago de Chile, Av. Ecuador 3769, Casilla 233, Santiago, 1, Chile and P. C. Moyano, Dept. of Chemical Engineering, Univ. de Santiago de Chile, PO Box 10233, Santiago, Chile.
Potato chips have been popular salty snacks for 150 years and its retail sales in US are about $6 billion/year representing 33% of the total sales on this market. Texture is an important parameter to be controlled during processing of potato chips together with color, oil and acrylamide content. The objectives of this work were to study: (1) the kinetics of browning during deep-fat frying of blanched and unblanched potato chips; (2) the kinetics of texture development of fried potato slices during frying. Prior to frying, potato slices were blanched in hot water at 85° C for 3.5 min. Unblanched slices were used as the control. Control and blanched potato slices (Panda variety, diameter: 37 mm, width: 2.2 mm) were fried at 120, 150, and 180 °C until reaching moisture contents of ≈ 1.8 % (total basis). Color changes were recorded at different sampling times during frying at the three mentioned temperatures using the chromatic redness parameter a*. Textural changes in fried potato slices were followed by the parameter Maximum Force (MF) extracted from the force vs. distance curves corresponding to different sampling times. Experimental data of surface temperature, moisture content and color change in potato chips during frying were fit to empirical relationships, with correlation coefficients greater than 90%. A first-order rate equation was used to model the kinetics of color change. In all cases, the Arrhenius activation energy decreases alongside with decreasing chip moisture content. Normalized Maximum Force (MF*) was used in modeling textural changes in the potato slices during frying in both the initial tissue softening process and the later crust development process. Higher temperatures accelerated these processes; however neither the temperature nor the pre-treatment had a significant effect (P>0.05) over the final texture of the fried potato chips.
71D-8
Evaluation of a multipurpose fruit and vegetable processor for long duration space missions
D. C. VOIT1, M. J. Ferrua1, M. R. Santos1, S. K. Singh2, and R. P. Singh1. (1) Dept. of Biological and Agricultural Engineering, Univ. of California, Davis, 1 Shields Ave, 1310 Bainer Hall, Davis, CA 95616-5294, (2) Biological and Agricultural Engineering, Univ. of California, Davis, 1 Shields Ave, 1308 Bainer Hall, Davis1, CA 95616
Looking forward, NASA's Advanced Life Support (AFT) is exploring the possibility of processing vegetable crops on long-duration missions. For this, a Multi-purpose Fruit and Vegetable Processor (MFVP), designed with tomato as a target, was built. The sensitivity of an enclosed ecosystem requires that equipment have minimal impact while food processed have maximum quality and yield. AFT compares potential technologies by quantifying impact using Equivalent System Mass (ESM), a composite metric of mass, volume, power, cooling, and crew-time. To minimize ESM, processes were streamlined. Following, equipment was tested to verify that designs did not sacrifice quality and functionality. Objectives were to simultaneously analyze the product quality, including drain-weight, damage, and integrity and factors affecting ESM for an MFVP. Tomatoes were harvested and processed through three operations, slicing, dicing, or finishing. For each operation, the MFVP was tested at 4 rotational velocities and evaluated using quality metrics. Power consumption, set-up and clean-up time were also measured. Sliced tomatoes were evaluated for drain weight, tearing, pieces and double cuts. Diced tomatoes were evaluated drain-weight, texture, using Kramer shear, and particle size distribution. Tomatoes for pulping were hot broken to 85o C. Juice consistency was measured using a shear range of 0–500 s-1 and bostwick consistometer. Results indicated that rotational velocity significantly affected all quality and power parameters except the particle size distribution of the diced tomatoes. It was also determined that a minimum rotational velocity was required for slicing and dicing, 12.6 m/s and 4.8 m/s respectively. The thickness and stability of juice increased with pulper speed. Data from verification tests can be used to evaluate the yield of MFVP system while quantifying the impact of operational settings on a life support system using ESM. Information about design and speed is useful in terrestrial tomato processing as well.
71D-16
Processing and properties of puffed potato-rice cakes
Puffed cereal snacks offer consumers delightful texture perceptions such as crispness. Although puffed rice and corn cakes have gained acceptance, lack of flavor limits their further increase in consumption. Potato has desirable and distinctive flavor after being processed, puffing of potato and rice blends may offer a new desirable snack product. The objectives of this study were to determine the optimal processing conditions of potato pellets and parboiled rice mixtures using a rice cake machine and to evaluate the quality of puffed potato-rice cakes. Potato pellets were prepared by extruding potato flour with a twin-screw extruder. The experiment was a 3×3×3×4×2 factorial design with two replications. Parboiled rice and potato pellets were blended in 100/0, 75/25, and 50/50 ratios and tempered to 8.5, 9.5, and 10.5% moisture contents. The blends were puffed at 221, 229, and 237°C for 5, 6, 7, and 8 s. Puffed cakes were evaluated for their color, texture, weight loss and microstructure. All the four processing variables had significant effects on the quality of rice-potato cakes. Most of the interaction effects were also significant. Higher temperature, longer time, higher moisture, and lower rice content led to rice-potato cakes with higher specific volume, lighter and more reddish and yellowish in color, firmer texture, and lower weight loss. Optimal processing parameters were 75/25 rice/potato, 9.5% moisture, 229°C heating temperature and 6 s heating time. At these conditions, the cakes were relatively high in specific volume (8.98 cm3/g), low in percent weight loss (12.42%), medium in hardness (13.19 N) and relative low in redness and yellowness. The microstructure of the rice-potato cakes produced at 229°C for 6 s heating time also showed nice and uniform puffed air cells. These results indicate that potato-rice cakes could be made using a rice cake machine. The products have distinctive and appealing flavor associated similar to baked potato and have the potential as a new snack product.
71D-21
Freeze-thaw stability of copolymerized hydrocolloidal solutions containing curdlan gum
L. N. Sadar, H.-L. CHENG, and Y. M. Lo. Dept. of Nutrition and Food Science, Univ. of Maryland, Food Bioprocess Engineering Lab., 3407 Marie Mount Hall, College Park, MD 20742
Composed of a three-dimensional structure stabilized by crosslinks connecting junction zones between molecules, curdlan gum forms highly viscous aqueous suspensions with shear-thinning properties. Known to form thermoreversible as well as irreversible gels via heating or addition of Ca2+ or Mg2+, curdlan gum, a microbial hydrocolloid, has been shown to offer distinct textural properties to a variety of food products. However, the role of curdlan in stabilizing textural attributes of frozen products undergone unintentional temperature abuse remains unclear. The objective was to investigate the effect of freeze-thaw cycles on the stability of copolymerized hydrocolloidal solutions containing curdlan gum. Hydrocolloidal mixtures containing curdlan were prepared respectively with xanthan gum, locust bean gum, carrageenan, and guar gum at various ratios. The solutions were stored at 4° C for 24 h and then subjected to five freeze-thaw cycles alternating between -16° C (18 h) and 25° C (6 h). After each cycle, the texture of thawed samples were tested for viscosity, storage (G') and loss (G”) moduli, gel strength, adhesiveness, syneresis, and heat stability. The viscosity of xanthan-curdlan combination was the lowest among all samples studied yet the most stable over the five freeze-thaw cycles, whereas a notable change was observed with locust bean-curdlan. Variations in the value of G' and G” were much significant when curdlan was mixed with carrageenan than with xanthan. The guar-curdlan combination not exposed to freeze-thaw treatment showed predominant elasticity; however, as the cycles continued a decrease in elasticity was observed. Curdlan in combination with guar or xanthan at 2% (w/v) total concentration showed the most stable gel strength, whereas carrageenan-curdlan had the largest decrease. Xanthan-curdlan showed the highest freeze-thaw stability in terms of adhesiveness, syneresis, and heat stability. Characterization of freeze-thaw stability and interactions between curdlan and other hydrocolloids enables precise combination of these polymers specific to desired applications.
71D-24
Bakery product characteristics as influenced by convection heat flux
M. R. ZAREIFARD1, M. Marcotte1, and V. Boissonneault2. (1) Food Research and Development Centre, Agriculture and Agri-Food Canada, Processed Plant Products, 3600 Casavant Blvd. W., Saint-Hyacinthe, QC J2S 8E3, Canada, (2) Univ. of Sherbrooke, 2500 Boul. de l'Université, Sherbrooke, QC J1K 2R1, Canada
Baking conditions including temperature profile of air, oven wall, and air velocity have a major influence on quality of products. Varying these conditions may result in the same amount of Total Heat (TH) delivered to the product, while product quality would not be necessarily the same. The objectives of this study were to determine the convection part of TH for different oven conditions providing same amount of TH; and to study its effects on the quality of product. Convection and TH fluxes were experimentally measured using h-monitor device for standard industrial cup cake baking profile, and four other oven conditions. Baking was performed using the same dough for all five conditions. Quality parameters including Moisture Content (MC), texture analysis, volume index, and color of the product were evaluated as affected by baking conditions. Radiation was always dominated over convection not in a linear pattern. Using standard profile, convection part was about 27% of the TH delivered to products; while it was about 11, 22, 33, and 37% for other conditions. MC was always higher at the middle part of the cake compare to the top, bottom and sides, however, compare to the standard, these values were about 1-2% less. Volume expansion index was also decreased up to 10% for other conditions. Texture properties including hardness, chewiness, and guminess were lower for the standard profile and increased by 30% for both extreme conditions. Top color appearance of the cake was always darker than standard; and more uniform for less convection compare to high convection conditions. Overall, compared to standard, maximum changes in quality parameters were observed when the convection part of TH was decreased. Practical knowledge of convection heat effects on the product quality is of great importance for optimization of the industrial baking conditions.
71D-26
Effects of hydrothermal treatments on water dynamics and textural properties of wheat starch
J. YI, Food Science and Technology, Univ. of Georgia, Food Science Building, Athens, GA 30602, W. L. Kerr, Dept. of Food Science and Technology, Univ. of Georgia, 122 Food Science Bldg., Athens, GA 30602-7610, and S. Choi, Food Science and Technology, Gyeongsang National Univ., 900 Gazwa-dong, Jinju, South Korea.
Hydrothermal treatments cause physical modification of wheat starch. Although these starches provide desirable physical properties to some foods, little is known regarding the water and polymer dynamics which contribute to these properties. Our objective was to compare the water dynamics and textural properties of starch before and after hydrothermal modification (annealing and heat-moisture) treatments using proton NMR and texture profiles analysis. The annealed starch was prepared with excess water at 50o C for 6, 12, and 48 hours. The heat-moisture modified starch was prepared at 100o C for 48 hours, with aw values of 0.33, 0.69, and 0.93. Gels were made by adding 0.5g of starch to 1.0g of distilled water, and were heated in a microwave for 40s at 800W. Transverse relaxation studies showed that native starch gels have lower T2 values compared with hydrothermally modified starch. The starch modified with heat-moisture treatment showed higher T2 values. For starch gels held at 8¨¬C for 21 days, the peak T2 of native and annealed starch decreased from 50~60 ms to 20~30 ms, but did not change significantly in heat-moisture treated starch from 50~60 ms to 40~50 ms. In comparison to native starch gels, heat-moisture gels had lower hardness and cohesiveness, which decreased with increasing aw. Annealed gels had greater hardness and cohesiveness, which increased with longer annealing times. Heat-moisture modified starch had more leached amylose with increased aw, while annealed starch had the same or a decreased amount of leached amylose with increased annealing time. These results indicated that hydrothermal treatments cause alterations within the granule structure and changes in the interactions with water. Water dynamics of wheat starch are affected by these modifications. An understanding of these changes will help processors better formulate products using modified starches.
71F-4
Chemical characterization and texture profile analysis of colored maize varieties from Tulancingo Valley (Mexico)
N. GUEMES-VERA, Instituto de Ciencias Agropecuarias- CICYTA, Univ. Autonoma del Estado de Hidalgo, Av. Universidad s/n C.P., Tulancingo Hidalgo, 43600, Mexico, M. I. Reyes-Santamaria, Instituto de Ciencias Agropecuarias- CICYTA, Univ. Autonoma del Estado de Hidalgo, Av. Universidad s/n C.P. 43600, Tulancingo Hidalgo, 43600, Mexico, S. Soto-Simental, Centro de Investigación en Ciencia y Tecnología de Alimentos, ICAp, Univ. Autónoma del Estado de Hidalgo, Av. Universidad Km. 1, Rancho Universitario, Tulancingo 43600, Mexico, A. D. Hernández-Fuentes, Univ. Autónoma del Estado de Hidalgo, Centro de Investigación en Ciencia y Tecnología de los Alimentos, Av. Universidad Km 1, Rancho Universitario, Tulancingo, Hidalgo, 43600, Mexico, E. N. Aquino-Bolaños, Univ. Autónoma del Estado de Hidalgo, Centro de Investigaciín en Ciencia y Tecnología de los Alimentos, Av. Universidad Km 1, Rancho Universitario, Tulancingo, Hidalgo, 43600, Mexico, E. Mercado-Silva, Programa de Posgrado en Alimentos del Centro de la República, Univ. Autónoma de Querétaro, Centro Universitario S/N, Cerro de las Campanas, Querétaro, 76010, Mexico, and G. Davila-Ortiz, V, Dept. de Graduados e Investigación en Alimentos (IPN-ENCB-DGIA)., IPN-ENCB-DGIA, Plan de Ayala y Prolongacion de Carpio s/n, Mexico D.F., 11340, Mexico.
Maize is believed to have been originated in
71F-9
Texture profile of Spirulina platensis gel candy of the royal chitralada project of Thailand
R. S. Chamul, C. Barnard, H.-J. Chuang, H. TRAN, J. Ritchie, and A. Lam. School of Kinesiology and Nutritional Science, California State Univ.-Los Angeles, 5151 State University Dr., PE 206, Los Angeles, CA 90032-4226
Spirulina platensis, a blue-green alga incorporated in gel candy (from
71F-10
Utilization of flaxseed and garbanzo flour to design a muffin targeted to Hispanic pregnant women
Studies have reported that nutrients can reduce birth defects; for example, garbanzo (chickpea) flour can reduce blood glucose and prevent anemia, very common during pregnancy. Flaxseed intake is beneficial to lower low-density lipoproteins, increase alpha linoleic acid, and provides benefits to the heart. This study's objective was to design a muffin using garbanzo and flaxseed flour aimed toward Hispanic women to meet nutritional needs and cravings during pregnancy. Seven treatments (control, 20%, 40%, and 60% flaxseed and garbanzo) with three replications were considered for this study. Color (L*, a*, b*) was measured,
82-3
Performance of specialty sorghums in whole-grain extrusion
A. J. PEREZ-GONZALEZ, R. D. Waniska, and L. W. Rooney. Dept. of Soil & Crop Sciences, Texas A&M Univ., 370 Olsen Blvd., Heep Ctr., 2474 TAMU, College Station, TX 77843-2474
Production of whole-grain foods is being investigated. The western diet is low in dietary fiber, which is lost during milling. Sorghum is the fifth most important crop, and is utilized in foods and feeds around the world.
The objective was to evaluate the influence of genotype and tempering time on the performance of specialty sorghums in high-temperature, short-time (HTST) extrusion of intact whole grain.
The sorghums used were: a Type III “High Tannin” (
Extrudates from high-tannin sorghum tempered for 24 and 72 h had a similar expansion ratio but different texture (9.63 vs. 7.20 N mean puncture force, respectively). The amylase digestion method determined the amount and size of retained enzyme-resistant particles in the extrudates. Amounts of retained enzyme-resistant particles were similar for both treatments, but differed in particle size.
Extrudates from waxy and heterowaxy sorghums had similar expansion ratio, while those from the white food-type sorghum were more expanded. Extrudates from the white food-type sorghum had the least firm texture (7.45 N) and the highest retention of enzyme-resistant particles (58%) among white sorghums, followed by extrudates from the waxy (7.69 N and 55%) and the heterowaxy (8.22 N and 51%, respectively) sorghums.
Performance of specialty sorghums in whole grain extrusion was affected by tempering time and genotype.
82-9
How does amylase extend shelf-stability of flour tortillas?
J. N. ALVIOLA and R. D. Waniska. Dept. of Soil & Crop Sciences, Texas A&M Univ., 370 Olsen Blvd., Heep Ctr., 2474 TAMU, College Station, TX 77843-2474
Stale tortillas are firm and crack when folded, thus, become unacceptable to consumers. Tortilla staling has been attributed to ingredients, processing conditions and flour components, specifically starch and protein. Addition of amylase to flour tortilla has been shown to extend shelf-stability. Comparing control and amylase-treated tortillas may help explain the staling process. The objective of this study was to determine the effects of amylase and storage time on physical properties, texture and starch characteristics of flour tortilla. Control and amylase-treated (0.15 g amylase/kg flour) flour tortillas were prepared using the standard baking procedure. These were sampled at 0.04, 1, 3, 7, 14 and 28 days after baking, and evaluated for physical properties, shelf-stability, pasting viscosity and carbohydrate profiles.Control and amylase-treated tortillas did not differ significantly in thickness, diameter or opacity. However, the treated tortillas were shelf-stable (i.e., did not break when rolled) for 28 d while the control tortillas broke after 14 d. The treated tortilla required more force (6.1 vs 5.2 N) and work (31.6 vs 20.2 Ns) before rupture on the 14th day. Control tortillas did not contain oligosaccharides at any point during storage. Enzyme-treated tortillas contained about 0.12 g oligosaccharides/g sample. The pasting viscosity analysis of methanol-stabilized samples revealed a 6o C lower pasting temperature, 0.6 min earlier peak time and 1300 cP lower peak viscosity for enzyme-treated vs control samples. The production of oligosaccharides from starch in the tortilla by amylase corresponded to the extension of shelf-stability of the flour tortillas. The loss of polymer structure of starch needs to be investigated further, but results of this study demonstrate that modifying starch functionality retards staling.
89A-9
Physicochemical properties of frozen ling cod (Ophiodon elongatus) as affected by fish antifreeze proteins and other cryoprotective agents
A. M. LICEAGA GESUALDO1, A. L. Creagh2, and E. C. Y. Li-Chan1. (1) Food, Nutrition and Health Program, The Univ. of British Columbia, 6650 NW Marine Drive, Vancouver, BC V6T 1Z4, Canada, (2) Michael Smith Laboratories, The Univ. of British Columbia, 237-6174 University Blvd, Vancouver, BC V6T 1Z3, Canada
Changes in texture and protein functional properties occur during freezing and frozen storage of fish, shortening its shelf-life. While a commercial blend of 4% sucrose with 4% sorbitol is widely used as a cryoprotectant, it can impart an undesirable sweet taste. Fish antifreeze proteins (AFPs) are known to modify and suppress ice crystal growth, making them potential alternatives to sucrose-sorbitol. However, AFPs have also been shown to induce intracellular ice formation causing cell damage. Our objective was to study the possible application of AFPs (antifreeze glycoprotein and type I AFP) as cryoprotectants for frozen fish mince. Mince from ling cod was subjected to freeze-thaw abuse in the absence (control) or presence of AFPs (5, 10, 50, or 500 ppm), AFPs (50 ppm) with 0.3% phosphates (
89A-30
Acid solubilization-isoelectric precipitation (acid-sip) to remove off-odors/flavors associated with farm raised Channel catfish (Ictalurus punctatus) fillets
R. L. NABORS, Animal Science, Oklahoma State Univ., Food and Agricultural Products Center Room 203, Stillwater, OK 74078-6055, K. K. Schrader, Microbiology, USDA, ARS, NPURU, Thad Cochran Research Center, P.O. Box 8048, University, MS 38677-8048, C. Kleinholz, Fisheries, Langston Univ., P.O. Box 730, Langston, OK 73050, and C. A. Mireles DeWitt, Dept. of Animal Science, Oklahoma State Univ., 104-E Animal Science Bldg., Stillwater, OK 74078.
Many catfish producers are burdened with the chronic management problem of off-odor/flavor (o-o/f) catfish from 2-methylisoborneol (MIB) and geosmin. The resulting o-o/f's decrease profit margins for producers because processing must be delayed. The objective of our research was to apply an acid solubilization process to evaluate its effectiveness at eliminating or reducing the off odors and flavors associated with o-o/f catfish fillets. Live Channel catfish were randomly placed in 3-250 gal. tanks for 24 hr. One tank was used as a control. The other 2 tanks were spiked with either geosmin or MIB at 1ppb. The catfish were subsequently harvested and fillets were processed into raw and cooked batters using acid-sip or no acid-sip. Proximate analyses, texture, sensory, and color analysis were performed, as well as gas chromatography analyses to determine geosmin and MIB concentrations in test samples. Acid-sip raw batters had lower concentrations of geosmin (0.308 ± 0.147 vs 0.579 ± 0.207 µg/kg) and MIB (0.509 ± 0.152 vs 0.939 ± 0.337 µg/kg) than no acid-sip. Cooked acid-sip batters had lower 2-MIB concentration (0.917 ± 0.263 vs 1.371 ± 0.39 µg/kg) than no acid-sip batters. However, cooked acid-sip batters had higher geosmin concentration than cooked no acid-sip batters (0.733 ± 0.489 vs 0.557 ± 0.149 µg/kg). Based on the texture data, the gel-strength properties of the acid-sip samples are maintained and some properties are slightly improved in comparison to no acid-sip samples. Fat content was significantly reduced in all raw acid-sip samples while protein and ash contents did not differ between acid-sip and non acid-sip samples. Our research indicates that the acid-sip process produced a low fat protein product with strong gel characteristics. Results also show that the process has the capability to lower o-o/f compounds. Further research is needed to refine the process and improve its efficacy.
89B-10
Effect of hydrocolloids on mechanical properties of trout (Salmo trutta) gels
A. RAMIREZ-HUERECA1, J. J. Gonzalez Cabriales2, G. Velazquez1, and J. A. Ramírez2. (1) Food Science and Technology, Univ. Autónoma de Tamaulipas, UAM-Reynosa-Aztlán, Calle 16 y Lago de Chapala. Col. Aztlán,
Restructured fish products can be elaborated from low commercial value species. Hydrocolloids improve functional and nutritional properties of restructured fish products; however, the effect on texture and color parameters is not always beneficial. Low-methoxyl amidated pectin (LM35) is a fiber hydrocolloid that facilitates the digestion and help to diminish the cholesterol level in blood. The objective of this work was to evaluate the effect of hydrocolloids (LM35 in combination with carrageenan, alginate, locust bean, or xanthan) on the mechanical properties of trout (Salmo trutta) gels. For this study fish gels were added with a mixture of LM35:hydrocolloid (carrageenan, alginate, locust bean, or xanthan gum) at 0:1%, 0.25:0.75%, 0.5:0.5%, 0.75:0.25%, and 1:0% ratio for each hydrocolloid. The effect of these additives on the gel properties was studied measuring color, water holding capacity (WHC) and the parameters (hardness, fractures, cohesiveness, springiness, elasticity and chewiness) calculated from texture profile analysis (TPA). Better mechanical properties were obtained with LM35:carrageenan mixture at 0:1% and 0.25:0.75%, while alginate, locust bean and xantan in combination with LM35 did not improve the gel texture. WHC and color in gels with mixtures of LM35:carrageenan were improved when compared with the other hydrocolloids used in this study. Also, the gels with LM35:carrageenan showed an appearance similar to surimi. The results obtained suggest that it is feasible to use LM35:carrageenan mixtures to improve the functional and mechanical properties of restructured fish products from trout.
89B-16
Effect of combining microbial transglutaminase treatments and high pressure processing on the mechanical properties of restructured products from arrowtooth flounder
R. M. URESTI, Food Science and Technology, Food Process Engineering Group at Oregon State Univ. and Univ. Autónoma de Tamaulipas, UAM-Reynosa-Aztlán, Calle 16 y Lago de Chapala. Col. Aztlán, Reynosa, Tam., 88740, Mexico, G. Velazquez, Food Science and Technology, Food Process Engineering Group at Oregon State Univ. and Univ. Autónoma de Tamaulipas and Oregon State University, UAM-Reynosa-Aztlán, Calle 16 y Lago de Chapala. Col. Aztlán, Reynosa, Tam., 88740, Mexico, J. A. Ramírez, Food Science and Technology, Univ. Autónoma de Tamaulipas, UAM-Reynosa-Aztlán, Calle 16 y Lago de Chapala. Col. Aztlán, Reynosa, Tam., 88740, Mexico, M. Vázquez, Food Science and Technology, Universidad Autónoma de Tamaulipas, UAM-Reynosa-Aztlán, Calle 16 y Lago de Chapala. Col. Aztlán, Reynosa, Tam., 88740, Mexico, and J. A. Torres, Dept. of Food Science & Technology, Oregon State Univ., Food Process Engineering Group, 100 Wiegand Hall, Corvallis, OR 97331-6602.
Interest in safer fish products by high pressure processing (HPP) is increasing. The muscle of arrowtooth flounder (Atheresthes stomias), an underutilized fish specie abundant in the
89B-20
Gelation of proteins recovered from krill
Y. C. Chen and J. JACZYNSKI. Div. of Animal & Veterinary Sciences, West Virginia Univ., PO Box 6108, Morgantown, WV 26506-6108
Antarctic krill (Euphausia superba) are small, shrimp-like crustaceans in the seas with largest biomass of any multi-cellular animal species on earth. Estimates state that 150 million metric tons (MT) of krill could be an annual sustainable harvest compared with 100 million MT of the total seafood harvest. However, small krill size and its endogenous proteases are the processing challenges, which resulted in failure of commercial krill fishery for human consumption. Our objectives were to recover krill proteins and investigate the effects of a mixture containing 2% (w/w) bovine plasma protein, 2% (w/w) potato starch, and 0.3% (w/w) polyphosphate on gelation of proteins recovered from krill. Whole krill were homogenized with water (1:6 w/v). Proteins were solubilized at pH 2.5 or 12.5 and separated from impurities using a centrifuge. Soluble proteins were precipitated at pH 5.5 and separated from water using a centrifuge. Krill pastes (78% moisture, 2% NaCl) with and without the mixture were prepared from recovered proteins and cooked in torsion tubes at 90o C for 15 min., yielding gels. The dynamic properties of the paste, and texture and color of the gels were compared. Storage moduli (G') of acid- and alkali-treated samples without the mixture dramatically decreased at 10 to 60o C and 40 to60 o C, respectively, then both G's increased from 60 to 90 o C. However, G' of samples with the mixture increased at 10 to 90o C. This data indicates that the strong proteolytic activity of krill endogenous enzymes can be suppressed by BPP. The krill paste without the mixture failed to gel, while the paste with the mixture resulted in a gel, which was evaluated with texture profile analysis, Kramer shear, and torsion test. The gels were pinkish due to asthaxantin as confirmed by L*a*b* values. Our study offers a method to recover proteins from krill to develop value-added foods.
89B-23
Development of temperature tolerant fish protein gels using special starches
A. L. HUNT, Dept. of Food Science & Technology, Oregon State Univ., OSU Seafood Research Lab., 2001 Marine Dr., Rm. 253, Astoria, OR 97103-3420 and J. W. Park, Department of Food Science and Technology, Oregon State University Seafood Laboratory, 2001 Marine Drive #253, Astoria, OR 97103.
Starch is the second most important ingredient in making surimi seafood. A wide variety of starches are used in the process each with unique functional properties that affect gel texture. Serving temperature plays a critical role in defining the textural quality of the final product. Most surimi seafood products are served cold. These products, however, usually perform poorly when served warm. The majority of starch research is conducted at room temperature with limited research regarding temperature stability of starch over a wide range of temperatures.
Objectives of this study were to investigate the effect of selected starches alone and in combination with other starches on texture, color, and moisture release as affected by various temperatures and storage conditions.
Twenty-five batches of
The two single starches with the best results, which minimized stickiness and maintained functionality over a broad range of temperature conditions were then combined with native potato and wheat starch and subjected to the same tests as described above.
By determining the affect of various starches over a range of potential serving temperatures, a combination of starch, which maintained its functionality over a range of temperatures, was determined for suitable use in surimi seafood products.
89B-27
Effects of myoglobin on the gelation properties of
J. PARK1, J. W. Park1, and Y. J. Choi2. (1) Food Science and Technology & OSU Seafood Laboratory, Oregon State Univ., 2001 Marine Drive #253, Astoria, OR 97103, (2) Division of Marine Bioscience, Gyeongsang National Univ., Tong Yeong, South Korea
Myoglobin is washed away during conventional surimi processing. There are two divided opinions about the effect of myoglobin on the gel forming ability of myofibrillar proteins (surimi): one side thinks it is negative, while the other side positive. With the application of a new method of fish protein isolation that retains myoglobin, there is a great need to refocus on the role of sarcoplasmic proteins such as myoglobin on the gelation properties of surimi. Our objectives were to determine the effect of myoglobin addition to the surimi gel quality and to understand the role in the gelation mechanism of myofibrillar proteins. Myoglobin was extracted from sardine (Sardinops sagax) fillet after homogenizing with 0.01 N sodium phosphate buffer (pH 6.3. The homogenate was centrifuged at 7000 rpm for 20 min and then the supernatant was treated with saturated ammonium persulfate. Precipitate was subjected to dialysis overnight. Recovered myoglobin was freeze-dried and stored at -70°ÆC until tested. Myoglobin solubility was measured in the range of pH 2 to 11. Various levels (0.2, 0.4, 0.6, and 1.0%) of myoglobin were added to
89B-28
Crab mince surimi: effects of cryoprotectants and freezing treatment
S. R. BAXTER, Dept . of Food Science and Human Nutrition, Univ. of Maine, 5735 Hitchner Hall, Orono, ME 04469-5735 and D. I. Skonberg, Dept. of Food Science & Human Nutrition, Univ. of Maine, 5735 Hitchner Hall, Orono, ME 04469-5735.
Crab processing typically involves hand picking claw and leg meat from cooked products. Remaining meat can be recovered using deboning equipment thereby reducing waste output. Minced meat can then be further processed into value added products. Gelation properties of thermally treated muscle proteins have yet to be reported. This study focuses on gel forming ability of processed crab mince. Objectives of the research were to determine if cryoprotectants, freezing and various heat treatments have an impact on gel formation of crab surimi. Previously frozen Jonah crab mince was washed to remove soluble components. Four different treatments were applied to the washed mince: 1) freezing with cryoprotectants, 2) freezing with no cryoprotectants, 3) no freezing with cryoprotectants, and 4) no freezing with no cryoprotectants. The cryoprotectant treatment was a combination of 4% sucrose, 4% sorbitol, and 0.3% polyphosphate. A control of unwashed mince was used for comparison. Following treatment, 2.5% NaCl was added to the surimi before gelation at 35°C/30min, 90°C/30min, or 35°C/30min followed by 90°C/30min. Gels were tested for moisture content, color, water holding capacity, and gel strength using the puncture test. The moisture of unwashed mince was significantly higher than that of the four treatments. Water holding capacity of gels was significantly different (p<0.05); gels with no added cryoprotectants had 10-20% greater water holding capacity than those with cryoprotectants. Color analysis data indicates frozen surimi with cryoprotectants was significantly more white than other treatments and all gels became more white after cooking. Frozen samples with no cryoprotectants and two stage heating exhibited significantly higher gel strengths than all other samples, approximately 10-fold higher than the gel strength of the softest samples.
Results indicate that suitable surimi gels can be formed using thermally processed crab mince. Future work will focus on optimizing gelation conditions for the crab mince.
89B-29
Texture analysis of gelatin water desserts made from fish gelatin
P. ZHOU, M. R. Ginsberg, S. J. Mulvaney, and J. M. Regenstein. Dept. of Food Science,
Flavored gelatin water desserts are very popular. However, commercial gelatin water desserts are generally made of gelatins from pork or non-religiously slaughtered beef, and unacceptable to Jews and Muslims. Some consumers are also concerned about BSE in mammalian gelatins. Fish gelatin could satisfy the requirements of these consumer groups. Our objective was to develop gelatin water desserts from fish gelatin and compare their textural properties with those from mammalian gelatin. Five gelatin water desserts were prepared by dissolving gelatin (3%, w/w) in hot flavored orange drink (12 to 14% sugar, w/w; pH 2.7 to 2.8) and then storing them at 2 to 4 °C for 24 h. Two of them were from fish gelatins (
89F-15
Effect of frozen storage on the gelling properties of giant squid (Dosidicus gigas) mantle muscle
E. PONCE-ALQUICIRA1, O. Dublan-García, and I. Guerrero-Legarreta. (1) Dept. de Biotecnología, Univ. Autónoma Metropolitana, Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340, Mexico
Gelling forming capacity is one of the most important properties for the seafood industry to fabricate surimi-type products from underutilized species as squid. Most seafood products are stored while frozen; however this storage condition induces severe changes in texture, protein denaturation and low functionality. The objective of this work was to study changes in gelling properties of myofibrillar proteins extracted from giant squid (Dosidicus gigas) mantle muscle stored at –20 and –80º C. Myofibrillar proteins were extracted from frozen squid mantle muscle by solubilization in high ionic strength solution; gels were formed by heating protein extracts in 0.5% phosphate buffer, 3.5% NaCl, pH 7, once cooled down, deformation curves were recorded in gels in a TA-XT2 with 75% penetration at 2.5 mm/sec. Free formaldehyde was analyzed using Nash reagent; total reactive SH groups were also analyzed by the Ellman method. Severe changes were found after four months of frozen storage. Gel strength decreased from 1.7 to 0.113 and 0.103 N at -20 and –80º C, respectively. Total sulfhydryl groups decreased from 100 to 58.49 and 64.46 mmol SH/mg protein at –20 and –80º C, correspondingly. Conversely, formaldehyde increased throughout storage from 1.33 to 3.2 and 3.5 mg/100g at –20 and –80º C, respectively. It is known that freezing induces dehydration that, in conjunction with formaldehyde could induce protein aggregation and SH groups decreasing, reducing gel strength. Squid mantle muscle is very sensitive to deterioration; therefore, information obtained in this study will be used to understand changes in squid mantle during freezing.
89F-16
Thermal gelation of squid surimi with pork, beef, and fish myofibrilar proteins
E. PONCE-ALQUICIRA1, Z. E. Vázquez-Zamorano, O. Dublan-García, and I. Guerrero-Legarreta. (1) Dept. de Biotecnología, Univ. Autónoma Metropolitana, Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340, Mexico
Giant squid is an abundant natural resource in
89F-24
Tenderness and sensory properties of fourteen major beef muscles
G. TORRESCANO1, A. Sanchez-Escalante1, P. Roncales2, J. A. Beltran2, and J. P. Camou1. (1) Dept. of Food Technology of Animal Origin, Centro de Investigación en Alimentación y Desarrollo, A.C., PO Box 1735, Hermosillo, Sonora, 83000, Mexico, (2) Dept. of Animal Production and Food Science/Food Technology Laboratory, Faculty of Veterinay, Zaragoza University, C/ Miguel Servet 177, Zaragoza, 50013, Spain
Beef quality appears to be determined chiefly by textural behavior. The objective of this work was to evaluate the instrumental and sensory tenderness of fourteen major beef muscles. The following 14 muscles from Swiss Brown young bull carcasses (485 ± 15 days) with similar genetic background and fed the same diet were analyzed at 24 hours postmortem: Biceps femoris (BF), Cuadriceps femoris (CF), Diaphragma (DI), Flexor digitorum (FD), Gluteus medius (GM), Infraespinatus (IE), Longissimus lumborum (LL), Longissimus thoracis (LT), Psoas major (PM), Pectoralis profundus (PP), Semimembranosus (SM), Semitendinosus (ST), Sternomandibularis (STER) and Triceps brachii (TB). Homogeneous samples of each muscle were cooked in a grill until the center reached 70ºC. Samples were evaluated by a six-member trained panel using a nine-point scale for initial hardness, total chew strain, final residue and overall tenderness. For instrumental texture assessment, a minimum of six cores (1 cm diameter) were removed parallel to muscle fiber orientation and sheared using a Warner-Bratzler device attached to a Texture Analyzer TA-XT2i. The peak force (kg) of the cores was recorded and analyzed. Regarding sensory analysis, PM and DI were the most tender muscles, showing the lowest initial hardness and chew strain, while LL and PP were found to have the lowest overall tenderness and the highest toughness parameters. Warner Bratzler shear force (WBSF) analysis demonstrated that PM and DI muscles were the most tender, while PP had the highest hardness values, in agreement with results of sensory panel; LL was not found to be a tough muscle, probably due to a lack of aging. High positive correlations were obtained between overall tenderness and WBSF (R=-0.640, p<0.01). Results demonstrated that different anatomical locations in the bovine carcass had large variations in tenderness, but it may depend on accuracy of analytical methods and aging grade of meat.
89G-3
Development of an improved gluten-free bread with dietary fiber, antioxidants, and omega-3 fatty acids
L. R. HINES, Cereal Quality Laboratory, Texas A&M Univ., 370 Olsen Blvd, Heep Center, Room 429, College Station, TX 77843 and L. W. Rooney, Dept. of Soil & Crop Sciences, Texas A&M Univ.
Gluten-free breads often have poor quality and are also low in health promoting compounds such as dietary fiber, antioxidants, and omega-3 fatty acids. Inulin, brown sorghum bran, and flax are good sources of these compounds. Increasing awareness about celiac disease will result in an increased diagnosis rate and more demand for improved quality gluten-free breads. The objective of this study was to improve the quality and nutritional content of gluten-free bread by substituting inulin, brown sorghum bran, and flaxseed for a percentage of the composite flour. These ingredients were substituted individually at 5% and 10% and in 50:50 combinations. The control contained no inulin, sorghum bran, or flax. Gluten-free batter was mixed with a stand mixer, scaled into pans, proofed, and baked with steam. Sorghum flour (30%), tapioca flour (30%), cornstarch (30%), and potato starch (10%) made up the composite flour. Minor ingredients were water, eggs, margarine, sugar, honey, non-fat dry milk, yeast, xanthan gum, gelatin, salt, and vinegar. Bread was evaluated based on specific volume, crumb firmness, color, moisture, flavor, and nutritional content. At 10% substitution, inulin increased specific volume and decreased crumb firmness over all of the treatments and the control. The addition of 2.5% flax and 2.5% sorghum bran to the 10% inulin formula did not significantly reduce specific volume or increase crumb firmness. This formula provided over 6 grams of dietary fiber per 56 g slice, as well as 323 mg omega-3 fatty acids and 2113 µg TE antioxidant activity. While high doses of inulin may cause gastrointestinal discomfort, the amount provided in a slice of bread is well tolerated. While adding dietary fiber to wheat-based breads generally decreases their quality, these results show that added dietary fiber can improve both the nutritional content and quality of gluten-free breads.
89G-14
Nutraceutical corn tortillas prepared using bran from specialty sorghums
G. CEDILLO, R. D. Waniska, and L. W. Rooney. Dept. of Soil and Crop Sciences, Texas A&M Univ., 370 Olsen Blvd., Heep Ctr., 2474 TAMU, College Station, TX 77843-2474
Inclusion of bran from specialty sorghums in corn tortillas could produce a tortilla rich in antioxidants. Some specialty sorghums have high levels of phenolic antioxidants. Since tortilla consumption is widespread and growing, they may be an appropriate vehicle for nutraceutical delivery. The objective of this study was to evaluate the effects of sorghum bran addition on corn tortilla properties and the retention of antioxidant activity. Tortillas containing 0, 5, and 10% bran from type III (sumac) and black sorghums were prepared from nixtamalized corn flour, stored for four days at refrigeration temperature, and subjected to analysis. Tortilla texture was measured by objective (extensibility) and subjective (rollability and pliability) tests. One-dimension extensibility test was conducted using the texture analyzer (TA.XT2i Texture Analyzer, Texture Technologies Corp.). Tortillas were also analyzed for phenols (Folin-Ciocalteu) and antioxidant potential (2,2(prime)-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Heating of 4-day refrigerated tortillas cause all treatments to be flexible and soft. Tortillas containing bran had more friable structure after reheating compared to control tortillas. Levels of phenols, antioxidant activity, and a bitter taste increased with increasing bran in corn tortillas. Retention of bran antioxidant activity after processing was between 50 and 70%. One serving (55 g) of tortilla containing 5% sumac bran had an antioxidant activity equivalent to that of 50 g of blueberries (fresh wt.). The antioxidant activity was retained through out corn tortilla processing; hence sorghum bran could be used as an ingredient in functional foods. The sorghum bran also gives the product a dark color, which is a characteristic associated with many healthy foods.
96-2
Shelf life extension of Cantaloupes using the VSV process
D. O. UKUKU, X. Fan, and M. F. Kozempel. Food Safety Intervention Technologies Research Unit, USDA-ARS-Eastern Regional Research Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038-8598
Minimally processed fruits and vegetables are more perishable than the intact products. They have a limited shelf life due to deterioration caused by spoilage microflora as well as physiological deterioration. Cutting may increase microbial spoilage of fruits through transfer of microflora on the outer surfaces to the interior tissue.
The objectives of this study were to use the Vacuum/Steam/Vacuum process to reduce indigenous spoilage microflora on the surface of cantaloupes. A second objective was to investigate the effect of such treatments on transfer of spoilage microflora from the cantaloupe surface to the fresh-cut melon during rind removal and cutting. Finally, the effect of such treatment on color and texture of the fresh-cut cantaloupes during storage at 5ºC or 10 ºC for up to 9 days was investigated.
Cantaloupes were treated in the VSV processor. Plugs from treated and control samples were stored at 5 and 10C for up to 9 days. Samples were monitored for the presence and growth of mesophilic bacteria, yeast and mold and pseudomonas spp every three days. Texture was evaluated with a TA-XT2i Texture Analyzer every three days during storage. Color (CIE L*, a*, b*) was measured with a ColorQuest XE colorimetric spectrophotometer every three days during storage.
VSV treatment resulted to a significant reduction of aerobic mesophilic bacteria, yeast and mold and Pseudomonas spp on cantaloupe surfaces. VSV treatment significantly reduced transfer of spoilage microflora that usually lead to decay of whole melon and fresh-cut pieces during storage and reduced transfer of spoilage microflora from whole cantaloupe surface to fresh-cut pieces during preparation. The spoilage microflora like yeast and mold were reduced to below detection level (< 1 CFU/g).
By extending shelf life the VSV process can reduce losses as well as improve the safety of cantaloupes.
96-3
Effects of dipping treatments on color stabilization and quality of apple cubes
Y. ZHU, Dept. of Food Science & Technology,
Dipping is an important and necessary pretreatment in processes of fruits and vegetables. It is used to prevent enzymatic browning caused by polyphenol oxidase. Several chemicals including ascorbic acid (AA), citric acid (CA) and calcium chloride (CC) have shown the capability of stabilizing color of cut apples during long time storage. However, effect of dipping solution concentration and time on the color stabilization has not been well studied. The objective of this research was to investigate the effects of the dipping solution concentration and dipping time on the color, texture and solid loss of fresh cut and infrared blanched apple cubes. Fresh cut 12.8 mm apple cubes were dipped in the solutions containing AA, CA and CC at different concentrations from 0.1% to 1.5% for various times from 0 to 10min. The solid losses of the samples were measured during dipping. Some of the dipped samples were further blanched with infrared heating. The color and texture of the dipped samples with and without blanching were determined after the samples were exposed in ambient air for different times from 0 to 100 min. The results showed that CA alone had almost no effect on preventing browning of the apple cubes. The combination of any two chemicals among the three chemicals tested could effectively reduce the enzymatic browning rate. No further color change was observed after IR blanching when apple cubes were dipped in 0.5%AA+0.5%CC solution for 5 min. Apple cubes treated with the combination of CA and AA showed poorest texture after IR blanching. The amount of solid loss was directly related to the dipping time. The research suggests that dipping with AA and CC solution is a very important pretreatment in apple blanching process to stabilize the color and improve the texture of blanched products.
97-1
Effect of razor blade penetration depth on correlation of razor blade shear values and sensory texture of broiler major pectoralis muscles
R. XIONG1, J.-F. C. Meullenet1, L. C. Cavitt2, and C. Owens2. (1) Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Ave., Fayetteville, AR 72704-5585, (2) Dept. of Poultry Science, Univ. of Arkansas
The Meullenet-Owens razor blade shear (MO) procedure is a novel shear method. It has the advantages of simplicity, no sample preparation and more rapid testing over traditional methods such as Allo-Kramer and Warner-Bratzler tests, thus resulting in potential labor savings in research and routine quality control. However, the effect of the penetration depth used in the MO shear test on the correlation between sensory and instrumental measurements has not been investigated. The objectives were to determine the minimum penetration depth for the MO shear test to obtain satisfactory correlations with sensory data and to develop a regression equation for calculating the equivalent MO razor blade shear energy (MORBE) at the penetration depth of 20mm. Birds were processed and the breasts were removed at one of 9 postmortem deboning times (0.25, 1.25, 2.0, 2.5, 3.0, 3.5, 4.0, 6.0, and 24.0 h). A 7-member trained panel evaluated the cooked samples for initial hardness, cohesiveness, moisture release, hardness of mass, cohesiveness of mass and number of chews. A 74-member consumer panel was used to evaluate the samples for acceptance of overall texture and tenderness, appropriateness of juiciness and tenderness, and intensity of tenderness. The MO shear test was used to instrumentally assess tenderness of breast meat with different penetration depths. Results show that the correlation between sensory and instrumental measurements was affected by the penetration depth used for the MO shear test. As the penetration depth increased, the correlation with sensory hardness and cohesiveness increased, while that with consumer acceptance of texture and tenderness decreased. A penetration depth of at least 10 mm is suggested for obtaining a “constant” correlation (0.82-0.85). MORBE was also affected by the penetration depth. The MORBE conversion factor was proposed to obtain equivalent MORBE values at a penetration depth of 20mm and can be used to convert MORBE values assessed at lower penetration depths. This study implies that MORBE is affected by penetration depth, but it can be converted to an equivalent MORBE value at a penetration depth of 20mm.
97-2
Novel shape profiling method for classifying tender and tough broiler breast meat
J.-F. C. MEULLENET1, R. Xiong1, A. Saha2, and C. Owens2. (1) Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Ave., Fayetteville, AR 72704-5585, (2) Dept. of Poultry Science, Univ. of Arkansas, Center of Excellence for Poultry Science, Fayetteville, AR 72701
There are various instrumental tests including the Allo-Kramer, Warner-Bratzler and Meullenet-Owens Razor Blade (MO) shear methods that can be used for assessing tenderness of cooked breast meat. However, these methods are destructive and impractical for on-line sorting tender and tough breast meat. A novel shape profiling method was proposed for on-line classification of tender and tough broiler breast muscles. The objective was to investigate the potential of the shape profiling method for classifying broiler breast muscles into tender and tough groups. Commercial birds (7 week old) were processed and the carcasses were deboned at 7 different times postmortem (0.25, 1.0, 1.5, 2.0, 4.0, 6.0 and 24.0 h). The non-destructive shape profiling system, which mainly consists of a conveyor belt, laser displacement sensors and a portable computer, was used to measure shape profiles of the deboned breast fillets. he shape profiles were related to instrumental tenderness measures. The breast fillets were then cooked using conventional ovens (350o F) for 40 minutes. The cooked fillets were stored at 4o C overnight and evaluated using the MO shear method and a texture analyzer. When the MO shear energy was greater than 150 Nmm, the fillet was considered tough; otherwise, the fillet was considered tender. Results show that MO shear energy increases as thickness of breast fillets increases, while it decreases as length and width increase. Early deboned breast fillets shrank more than late deboned ones. For tough fillets deboned at 1.0 h postmortem, one out of 20 fillets was misclassified as tender, while one out of 20 tender fillets (24 h postmortem) was classified as tough. Overall, the rate of correct classification of tender and tough meat was 83.1% for all breast samples (n=130). This study implies that the proposed shape profiling method is a promising technique for on-line classification of tender and tough poultry breast meat.
97-3
Classification of tender and tough broiler breast meat by a non-destructive deformation test
R. XIONG1, J.-F. C. Meullenet1, and C. Owens2. (1) Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Ave., Fayetteville, AR 72704-5585, (2) Dept. of Poultry Science, Univ. of Arkansas, Center of Excellence for Poultry Science, Fayetteville, AR 72701
Tenderness has long been identified as the most important factor determining consumer-eating satisfaction of poultry meat products. As consumer consumption of boneless breast meat has dramatically increased over recent years, tenderness has become increasingly important to poultry meat processors. Destructive instrumental tests such as Allo-Kramer (AK), Warner-Bratzler (WB) and Meullenet-Owens Razor Blade (MO) shear methods are available for assessing tenderness of cooked breast meat. However, there is little information on non-destructive instrumental tests for classifying tender and tough breast meat. The objective was to investigate the potential of a non-destructive deformation test for classifying tender and tough breast meat. Commercial birds (7 week old) were processed and the carcasses were deboned at 9 different times postmortem (0.25, 1.25, 2.0, 2.5, 3.0, 3.5, 4.0, 6.0 and 24.0h). The non-destructive deformation test was performed on the raw breast fillets using a Texture Analyzer with four different cylindrical probes (diameter of 2, 5, 6, 8 mm). The breast fillets were then cooked using conventional ovens. The cooked fillets were stored at 4oC overnight and evaluated using the MO shear method. If the MO razor blade shear energy was greater than 150 Nmm, the fillet was considered tough; otherwise, the fillet was tender. Results show that the correlation coefficient (r) between the razor blade shear energy and deformation was approx 0.6 (p<0.001) for the probe (8 mm diameter). Early deboned breast fillets (0.25 and 1.25 h postmortem) showed less deformation than late deboned breasts. For tough fillets deboned at 0.25 and 1.25 h postmortem, only 2 fillets out of 40 were misclassified as tender, while one out of 14 tender fillets (24 h postmortem) was misclassified as tough. Overall, the correction rate of classification of tender and tough meat was 81% for all breast samples (n=148). This study implies that non-destructive deformation test could be useful for on-line classification of tender and tough poultry meat.
97-4
Effect of thawing methods on yield and tenderness of beef loin steaks
J. S. Eastridge, A. R. GOZORA, and M. B. Solomon. Food Technology and Safety Laboratory, USDA, Agricultural Research Service,
Ice crystal formation and growth during freezing, storage and thawing can degrade meat quality. Apart from food safety, little attention has been given to thawing methods. This study examines thawing method effects on yield and tenderness of meat. Four beef strip loins were vacuum packaged (VP) and frozen in a commercial freezer at -23° C for 5 mo. Starting from the anterior end, frozen loins were cut into 2.7 cm thick steaks (n=9) to assure 2.5 cm on thawing and were individually VP. Thawing methods, randomly assigned each series of three steaks, were slow (S; 18-26 hr at 4° C), fast (F; 20 min at 20° C) or very fast (V; 11 min at 39° C). After thawing, F and V steaks were placed in ice slush for 5 min. Steaks were grilled to 71° C, turning once at 40° C. Steak weights, temperatures and cooking time were monitored. Cores were removed parallel to the fiber axis from room temperature steaks and shear force measured on a texture analyzer with a Warner-Bratzler meat shear blade at 250 mm/min crosshead speed. Data were analyzed as a randomized complete block design using the MIXED procedure of SAS where loin represented block and treatments were repeated three times per loin. Among thawing methods, no differences were detected (p >0.05) for steak weights, thaw drip loss or thawed internal temperature. Cook yield was 2% higher (p <0.03) for rapid methods, F and V, compared to S. Total loss (drip + cook) was less (p <0.03) for F than S (25.5 vs 28.2%) while V (26.6%) was similar to F and S. Thawing method did not influence shear force (p >0.05); however, S had higher (p <0.04) standard deviation than F or V (1.14 vs 0.97 and 0.98 kgf). Rapid thaw methods F and V were advantageous to S in cook yield and less variable texture. Freezing meat adds convenience for researchers, restau-ranteurs and consumers. Rapid thawing allows better use of time, and increased yield may improve juiciness perception.
99B-2
Physico-chemical properties of gluten-free pancakes from rice and sweet potato flours
F. F. SHIH, Food Processing and Sensory Quality, Southern Regional Research Center, 1100 Robert E Lee Blvd, New Orleans, LA 70124, V. D. Truong, USDA-ARS, SAA Food Science Research Unit, Dept. of Food Science, Box 7624, North Carolina State Univ., Raleigh, NC 27695, and K. W. Daigle, Food Processing & Sensory Quality, Southern Regional Research Center, 1100 Robert E Lee Blvd, New Orleans, LA 70124.
The prevalence of celiac disease (CD), an intolerance of gluten, has been reported to be as high as 1 in 200 of the world population. CD is a serious health issue and it can only be treated by strict adherence to a gluten-free diet. To reformulate popular wheat-based products, such as pancakes, to be gluten-free, flours from rice and sweet potato have been used as wheat flour substitutes. However, there is scant information in the literature on the effect of totally substituting wheat flour with rice and sweet potato flours in the traditional wheat pancakes. In this study, our objective was to develop gluten-free pancakes to meet the need of people with CD problems. We prepared pancakes using different ratios of rice and sweet potato flours, and studied their rheological, nutritional and textural properties. Gluten-free pancakes were prepared using rice flour and rice flour replaced with various amounts, at 10, 20, and 40%, of sweet potato flour. Standard methods and instruments were used for the analysis of batter viscosity, textural properties and nutritional properties of the cooked pancakes. The apparent viscosity of pancake batters increased with increased sweet potato flour replacement. Overall texture properties of the rice pancakes were improved with the incorporation of the sweet potato flour and, at 20 to 40% sweet potato flour, became comparable to those of the traditional wheat pancake. Nutritional properties of the rice-sweet potato pancakes differed slightly from those of their wheat counterpart; however, the beta-carotene content increased substantially when sweet potato flour was incorporated. The incorporation of sweet potato flour in the formulation of rice pancakes was found to be desirable. Overall textural and nutritional properties were improved. Particularly, rice-sweet potato pancakes had substantially higher contents in beta-carotene, which make them nutritionally superior to traditional wheat pancakes.
99C-16
Radio frequency assisted hot water treatment of oranges to control Mediterranean fruit fly
S. L. BIRLA1,
There has been increased interest in using non-chemical quarantine treatment methods for control of fruit flies in citrus for international and some inter-state trades. Thermal treatments have been used for pest control in other commodities treatments, including mango and papaya, and may hold potential for citrus. Use of Radio Frequency (RF) energy in heating of oranges can cut down the process time required for accumulation of thermal lethality at core of the fruits as compared with the conventional heating. A reduction in process time will help to preserve the postharvest quality of treated citrus. Objectives of this research were to explore the possibility of using RF heating as a means to overcome the shortcoming of conventional hot water heating, and to determine the suitable process parameters for RF assisted hot water heating to control Mediterranean fruit fly in oranges based on the quality evaluations. The oranges were subjected to RF assisted hot water treatment (preheating in 35° C water for 45 min followed by RF heating to 48° C fruit temperature then holding in 48° C hot water for 15 min). The fruit quality after RF treatments was compared with those subjected to conventional hot water treatment at 48° C for 2.5 h. The postharvest quality attributes such as color, firmness, weight loss and change in flavor components were evaluated after 10 days of cold storage of the treated oranges. Use of supplemental RF energy in the treatment substantially reduced process time required for accumulation of lethality corresponding to 100% mortality of the fruit flies in the oranges. RF assisted hot water treatment preserved the acceptable quality attributes in treated fruits in comparison with conventional hot water treatment. These results suggest that a thermal treatment protocol that uses combination of hot water and RF heating can be developed to improve heating uniformity, reduce the process time and ensure product quality. However further investigations such as efficacy, long term storage and sensory evaluation are needed to develop a feasible treatment application based on the RF energy.
99F-12
Texture and flavor changes of stored dark chocolate by descriptive analysis
L. M. ANDRAE, S.-Y. Lee, and N. J. Engeseth. Dept. of Food Science and Human Nutrition,
Cocoa butter has a very distinct texture due to unique interactions of polymorphic lipid structures. Various storage conditions will lead to fat or sugar bloom. Part of the appeal of chocolate is the smooth mouthfeel; as bloom forms, a textural change is perceived. The objective was to analyze texture and flavor of dark chocolate stored under various conditions by both instrumental and sensory measurements. Dark chocolate was stored for 8 wk at ambient (23.0 °C) and frozen (-20.0 °C) conditions, in humidity chambers (23.0 °C, 57.6%, and 75.3%RH), and incubators with and without temperature fluctuations (30.5 °C and 30.5 ± 2.2 °C). Samples were evaluated at 0, 4, and 8 wk of storage for all analyses. Twelve descriptive panelists (f=9, m=3) were trained for 20 hr over 4 wk to analyze texture, flavor, and Time-Intensity assessment of melting time, after which each sample was evaluated in duplicate. Instrumental texture was measured in duplicate using a TA-XT2 Texture Analyser with a two-bite compression test (25% compression), while color (L, a, b, WI) was determined in triplicate by a Minolta ChromaMeter. Results were analyzed by ANOVA, LSD, and Cluster Analysis. Hardness, cohesiveness, chewiness, dry mouthfeel, sweetness, cream flavor, and melting time were found to be significantly different over treatments (P < 0.05). Temperature fluctuations were found to cause the most difference in texture and flavor, while high temperature without fluctuations also affected the texture and flavor, although to a lesser extent. Length of storage had a greater effect than relative humidity on texture and flavor attributes. Texture analyzer results indicated that temperature fluctuations decreased hardness, possibly due to an increase in fracturability/decrease in cohesiveness. Temperature fluctuations also significantly increased all color parameters, including Whiteness Index, due to fat bloom formation. In conclusion, storage at high temperatures, especially with fluctuations, has a large impact on chocolate texture and flavor.
99F-23
Sensory evaluation of irradiated and nonirradiated poultry breast meat infused with plant extracts
T. M. RABABAH, N. S. Hettiarachchy, and S. Eswaranandam. Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Ave., Fayetteville, AR 72701
Irradiation has been known as one of the most effective technologies in reducing the number of pathogenic microorganisms in food products. However, undesirable sensory quality changes such as lipid oxidation, off-flavor, and pink/red color may occur during irradiation that affect product quality and acceptability by consumers. This study evaluated the effectiveness of natural antioxidants: Green Tea (GT)and commercial Grape Seed (GS) extracts/combinations on sensory properties of nonirradiated and irradiated chicken meats. Fresh boneless and skinless chicken breast meats were vacuum-infused with plant extracts: GT/GS extracts alone or in combination, and irradiated at 3.0 kGy dosage. Irradiated and nonirradiated chicken breasts using instrumental, descriptive, and consumer tests were evaluated in this study. Descriptive results showed that irradiation did not affect the sensory flavor attributes (P< 0.05) except of brothy flavor, and irradiation increased texture attributes of hardness, cohesiveness, and hardness and cohesiveness of mass. Consumer results showed that GT and water control gave the best color (P< 0.05), followed by the combination of GS and GT extracts, and GS extracts, respectively, and the panel indicated that irradiation decreased the tenderness of the samples. Instrumental measurements showed that irradiation increased maximum shear force, shear work, hardness, and chewiness (P< 0.05) of cooked meats, and the addition of GT extracts improved the color compared with GS extracts and the combination of raw and cooked meats (P< 0.05). Infusion of extracts/combinations into chicken breasts increased lightness and decreased redness (P< 0.05) as well as the hardness of meat texture. Infusion of chicken meat with GT extracts at 3000 ppm is an effective method to minimize major sensory changes caused by irradiation..
