ROLE OF OIL ON PHYSICAL PROPERTIES OF CORN MASA FLOURS AND SENSORY CHARACTERISTICS OF CORN TORTILLAS

This study was conducted to evaluate the effect of oil on physical properties of corn masa and sensory of tortillas. Oil from commercial and lab-made whole dry corn masa (DCM) was extracted with hexane. Both flours were reconstituted with 2, and 4% w/w of commercial corn oil, to have 50 and 100% oil reconstituted flours. These levels of reconstitution were to determine the impact of oil on dough properties and sensory characteristics of corn tortillas. The sensory analysis of both types of flours showed the same patterns. The absence of oil did not affect dough stickiness or tortilla reliability. But, low content of oil did adversely and significantly (p<0.05) affect the typical corn tortilla flavor. Presence of oil significantly improved tortilla firmness and chewiness.     

Identifying drivers for consumer acceptance and purchase intent of corn tortilla

ABSTRACT:  The traditional production of corn tortilla has been modified by new processing technologies to make possible a commercial-scale production; this practice has resulted in products having sensory properties different from those produced by the traditional method. There is no published information on sensory attributes driving acceptance and purchase intent of corn tortillas. Identifying sensory drivers for acceptance and purchase intent of corn tortillas will help commercially produce products that satisfy consumers' expectations. A consumer study was conducted to evaluate acceptance and purchase intent of corn tortillas and determine drivers of acceptance and purchase intent of the products. Ten samples of corn tortillas were selected to represent a variety of corn tortillas available in the Mexican market. Three hundred Mexican consumers evaluated acceptability of appearance, color, thickness, rollability, resistance to tearing, aroma, chewiness, taste and aftertaste, and overall liking using a 9-point hedonic scale. Overall acceptance and purchase intent were determined with a yes/no scale. Analysis of variance and multivariate analysis of variance revealed that consumers were able to differentiate differences in sensory acceptability among 10 samples. For example, 2 homemade and 1 small commercial-scale samples, with an overall liking score of 6.6 to 6.7, were more acceptable than others. Rollability, resistance to tearing, and chewiness were attributes underlying overall differences among 10 samples. Attributes determining overall acceptance of corn tortillas were chewiness and overall liking. Purchase intent was influenced by overall appearance, rollability, chewiness, taste, and overall liking. This study revealed critical sensory attributes and their weights given by Mexican consumers when making decisions for acceptance and purchase intent of corn tortilla.     

Nutritional Composition of Corn and Flour Tortillas

Corn and flour tortillas were sampled at 2-wk intervals for 6 wk from five tortilla factories and the nutritional composition determined. Corn tortillas were found to be slightly lower in protein, thiamin, riboflavin and niacin when compared to white enriched bread. A lowering of the pH of the corn masa to 7.3 or lower improved the retention of these vitamins. Flour tortillas were found to be comparable in nutrition to white enriched bread when enriched wheat flour was used in the manufacture of tortillas. A wide variation was found to exist in the nutrient composition of both corn and flour tortillas manufactured by the different factories. This variation is attributed to different formulation procedures at the tortilla factories.     

Proximal composition and in vitro starch digestibility in flaxseed‐added corn tortilla

BACKGROUND: The effect of addition of flaxseed flour (10:90, 15:85 and 20:80, w/w) on the chemical composition and starch digestibility of corn tortilla was investigated. Tortillas were baked and frozen in liquid nitrogen, freeze‐dried, ground and analyzed for fat, protein, ash, total starch (TS), available starch (AS) and resistant starch (RS) contents as well as for starch hydrolysis rate and predicted glycemic index (pGI). Tortillas made from commercial nixtamalized corn flour were used as control sample. RESULTS: Flaxseed flour addition increased the fat and protein content of tortilla, whereas TS and AS decreased. TS was 15.25% lower in the 20% flaxseed‐containing tortilla as compared to the control sample. The AS content was 12.65% lower in the composite tortilla. RS content in the samples ranged between 1.92% for the control sample and 5.08% for the tortilla containing 20% flaxseed. The reduced enzymatic starch hydrolysis rate and pGI recorded for the flaxseed‐added tortilla, indicated slow digestion features. CONCLUSIONS: Flaxseed‐added tortilla might be used to increase the consumption of α‐linolenic acid in the daily diet and modulate starch digestibility of corn tortilla. This kind of product may be used by people with special diet reqirements. Copyright © 2008 Society of Chemical Industry     

QUANTIFYING TEXTURE CHANGES IN CORN TORTILLAS DUE TO STALING

The change in texture of corn tortillas due to staling is described using stress relaxation methods. Tortilla strips (70 × 35 mm) were subject to stress relaxation under tension at 3% strain. Force versus distance values were transformed into the textural indicator of stiffness. Fresh corn tortilla had significantly lower stiffness values than the stale tortilla (up to 10 days old). Stiffness decreased with increasing storage temperature from 6C up to 35C. The stiffness value from stress relaxation tests may be used as an objective indicator of tortilla texture.     

Prediction of Mechanical Properties of Corn and Tortilla Chips by Using Computer Vision

Deep-fat frying is a unit operation which develops unique sensorial attributes in foods. For instance, texture is the principal quality parameter of tortilla and corn chips. On the other hand, computer vision is a useful tool for quality evaluation and prediction of some physical properties in different either raw or processed foods. The objective of this research was to characterize corn and tortilla chips by using computer vision, and to build proper mathematical models which permit to predict mechanical properties of these chips (maximum force, such as hardness, and distance to maximum force, such as toughness) by using chromatic features extracted from their corresponding digital images. Corn and tortilla chips (thickness of 2 mm; diameter of 37 mm) were made from masa of maize and fried at constant oil temperatures of 160, 175, and 190 °C. A high linear correlation (R ² > 0.9400) was obtained between mechanical properties and some image features (Hu, Fourier, and Haralick moments). Cross-validation technique demonstrated the repeatability and good performance (>90%) of the models tested, indicating that can be used to predict the textural properties of the tortilla and corn chips by using selected features extracted from their digital images, without the necessity of measuring them in a texture analyzer.     

基于模糊数学感官和响应面法研制豆渣麻花及品质分析

本文以豆渣粉和中筋粉为主要原料,辅以泡打粉、植物油、蔗糖、全蛋液进行豆渣麻花的研制.在单因素实验的基础上,利用模糊数学感官评价法和响应面优化法对影响豆渣麻花感官品质的蔗糖添加量、植物油添加量、豆渣粉添加量进行优化,并对最后成品的营养成分、理化指标和微生物指标进行相关测定.豆渣麻花的最佳工艺配方为:豆渣粉添加量14％(豆...     

Corn Sweeteners in Ham Formulas

Corn sweeteners were compared with sucrose in cure formulas for hams. Thirty-six hams were randomly treated with nine sweetener treatments replicated four times. Combinations of sucrose, 55% high fructose corn syrup, 42% high fructose corn syrup, and high maltose corn syrup were used in brine formulas for pumping the hams. Sensory evaluations found no significant difference between sweetener type and sensory scores on color, flavor, tenderness, and overall satisfaction. However, ham weights appeared to be affected slightly by sweetener type. Sucrose produced greater ham yields at a 3% sweetener level. However, 55% high fructose corn syrup at 3.15% equalled the yield observed for sucrose. Forty-two percent high fructose corn syrup at greater than 3.3% solid level approached the yields observed for sucrose. Since sensory factors do not appear to be affected by corn syrup solids, only economic and yield factors need bc considered for their use in commercially produced hams.     

Modeling preference of commercial toasted white corn tortilla chips using proportional odds models

Eleven commercial toasted white corn tortilla chip products from the United States were evaluated by a group of 80 consumers of age 18–35 and by a trained sensory panel. Proportional odds models in conjunction with principal components were used for internal and external preference modeling of tortilla chip consumer overall acceptance. The internal preference modeling showed that flavor was the most important attribute to consumer overall acceptance followed by the interaction of appearance by flavor and texture. The external preference modeling showed that one flavor attribute (salt aftertaste) and one texture attribute (crispness) contributed significantly to increase consumer overall acceptance, whereas one appearance attribute (instrumental color a¹) significantly lowered consumer overall acceptance. The information reported in this study is important to the tortilla chip industry to produce tortilla chips with greater consumer acceptability. This study implies that proportional odds model using principal components is an alternative tool for consumer preference modeling.     

CHARACTERISTICS OF BEEF PATTIES USING OKARA POWDER

Four different levels of okara powder (2.5, 5.0, 7.5 and 10%) were used to obtain beef patties that were compared with controls with 10 and 20% fat. Okara addition affected some quality parameters of beef patties. Although the protein, fat, ash and carbohydrate contents of raw beef patties increased by the addition of okara, moisture content decreased. The same trends (except protein content) were observed after cooking. The addition of okara reduced the cholesterol content by about 2–28% for raw beef patties and 6–23% for cooked beef patties. However, addition of okara increased the energy values for raw and cooked beef patties with respect to control with 10% fat. The WHC, cook loss and shrinkage of beef patties improved by the addition of okara. The addition of okara increased the pH, L* and b* values of raw beef patties, but did not affect a* value. The effect of okara on the sensory properties was statistically significant and the overall acceptability scores of samples decreased after more than 7.5% okara powder addition . According to these results, addition of okara powder up to 7.5% can be recommended as an extender in beef patties production to improving certain quality parameters.

PRACTICAL APPLICATIONS

Okara is an abundant by-product of the soy and tofu industries and contains valuable components, including proteins, lipids, fibers and isoflavonoids. The addition of okara powder to beef patties reduces the cholesterol content and improves WHC, cook loss, shrinkage and sensory quality of the products. Okara powder can be added up to 7.5% for the production of patties.     

Effect of Retrograded Waxy Corn Starch on Bread Staling

Waxy corn starch pastes (10%) were stored at 5 °C for up to 35 days, and the powder specimens of retrograded starches thus obtained were added to wheat flour for bread baking at a level of 5%. The effect of retrograded starch on the staling of bread was determined. The loaf which contained retrograded waxy corn starch, which was prepared by storing the 10% paste at 5 °C for 7 days, showed an increase in specific volume and the results of the sensory evaluation showed that it was very acceptable. During the storage of bread, the increase in firmness and decrease in degree of gelatinization were suppressed by adding retrograded waxy corn starch. The moisture content of bread crumbs did not relate to firmness. Added retrograded waxy corn starch decreased the final viscosity of flour. The crystalline region of retrograded waxy corn starch used for bread baking included longer chains from amylopectin which in raw starch occurred in the amorphous region.     

添加玉米粉对蛋糕品质影响的研究

通过检测蛋糕的质构特性、理化性质和感官性质,系统地分析了玉米粉对蛋糕品质影响,并通过正交试验,以感官品质为考核指标,确定了玉米蛋糕的最佳配方和玉米最佳粉碎粒度。玉米蛋糕不仅具有保健功能,而且具有较好的感官品质。     

蒸汽爆破对豆渣膳食纤维的影响及在韧性饼干中的应用

本文研究了蒸汽爆破(SE)处理对豆渣膳食纤维组成及含量的影响,以及添加汽爆豆渣对韧性饼干感官品质的影响。结果表明,汽爆处理对豆渣膳食纤维组成及含量有较大影响,随汽爆强度增加,豆渣可溶性膳食纤维(SDF)含量呈上升趋势,在1.5 MPa/30 s时达最大值36.28%;汽爆强度进一步增大,TDF和SDF含量都呈下降趋势。豆渣粉在韧性饼干中的添加量不宜超过5%,否则饼干品质下降明显;豆渣经汽爆处理后,其添加量增至10%,对饼干品质有较大改善。研究表明,适宜强度的汽爆处理可大幅提高豆渣中SDF含量,改善豆渣在韧性饼干中的添加应用效果,这为豆渣的开发利用提供了有效途径。     

Composition and characteristics of oil extracted from flaxseed-added corn tortilla

Flaxseed has recently gained attention as a functional food, and the effect of adding flaxseed (10%, 15%, and 20%) to tortillas was evaluated. The physicochemical characteristics and the free fatty-acid (FFA) content of the oil extracted from flaxseed-added corn tortilla were determined. The results showed that the lipid (4.27%) and protein content (9.10%) of the control sample was statistically lower (p ? 0.01) than the tortillas added with flaxseed. In general, the total amylose content did not change with the flaxseed-added content; however, the amylose apparently decreased with the amount of flaxseed, indicating the presence of starch–lipid complexes. The saponification value was 95.37 (mg KOH/g oil) in the tortilla added with 10% flaxseed and increased to 100 (mg KOH/g oil) for the 20% flaxseed treatment. The peroxide value was observed to increase (p < 0.05) when the flaxseed flour was added at 10%, 15%, and 20%. In this study, the tortillas exhibited a high amount of total unsaturated fatty acids, 26.32–30.08% (oleic acid). Thus, the flaxseed-added corn tortilla could represent a valuable staple in improving the nutritional value of the original food product.     

玉米脆皮肠的研制开发

本文对脆皮肠中添加一定量的玉米粒对脆皮肠感官评价的影响作了研究，通过单因素和正交试验表明：玉米脆皮肠的最佳配方为：猪肉100％（肥瘦比为2：8），玉米碎粒15％，卡拉胶0．8％、大豆蛋白5％、玉米淀粉10％、复合磷酸盐0．4％、食盐6％、香辛料1％、味素0．3％、白糖1．5％、料酒1．2％、红曲红色素0．05％、水适量。     

Chemical composition and in vitro starch digestibility of corn tortillas with added amaranth flour

Background: Corn tortillas containing 20% (w/w) amaranth flour (AF) were kept in cold storage and analysed after various times for chemical composition and in vitro starch digestibility, including predicted glycemic index. Comparison was made with traditional nixtamalised corn flour (NCF) tortillas. Results: Lipid and protein contents were higher in mixed NCF/AF tortilla than in NCF tortilla. Available starch (AS) content was lower in NCF/AF tortilla and decreased during cold storage. However, this decrease was greater in NCF tortilla, suggesting slower starch retrogradation in NCF/AF tortilla. After 96 h of storage, total resistant starch (RS) content was higher in NCF tortilla than in NCF/AF tortilla. However, no differences were detected thereafter, indicating similar retrogradation after long storage times. Retrograded resistant starch contents indicated that only part of the total RS in tortilla is due to retrogradation, which agrees with the tendency recorded for AS and RS in both types of tortilla. α‐Amylolysis rates were similar in NCF/AF and NCF tortillas, decreasing with storage. The predicted glycemic index was always higher in NCF/AF tortilla, a pattern that might be due to the waxy‐type starch present in AF. Conclusion: NCF/AF tortilla might be suitable as a product with higher protein content and higher glycemic index than conventional NCF tortilla. Copyright © 2007 Society of Chemical Industry     

Nutrient addition to corn masa flour: effect on corn flour stability, nutrient loss, and acceptability of fortified corn tortillas

BACKGROUND: Iron, zinc, and vitamin B complex are among the most prevalent nutritional deficiencies in Mexico, with iron deficiency being the leading cause of anemia. Mexico has the highest per capita consumption of corn in the world, consumed mainly as tortilla. Thus, corn flour for making tortillas has been suggested as an effective strategy to overcome malnutrition in developing countries such as Mexico where corn is a staple food. The stability of micronutrients added to food is an important factor for the success of fortification programs. OBJECTIVE: The aim of this study was to evaluate the stability of corn flour fortified with micronutrients, and to measure the effect of micronutrient fortification on the sensory quality and stability of the fortificants in fresh and stored tortilla. METHODS: A commercially homogenized nonfortified corn flour (NCFC) produced from degermed white corn was fortified with a premix containing iron, zinc, thiamin, and riboflavin. Changes in thiamin, riboflavin, iron, and zinc content in fortified corn flour (FCF) and nonfortified corn flour (NFCF) during storage were investigated. Vitamin B1 and B2 content was determined by fluorescence spectroscopy while iron and zinc content was analyzed by atomic absorption. RESULTS: Thiamin content in FCF and NFCF showed a significant (p < .05) decrease (24% and 37%, respectively) after 90 days of storage. Riboflavin losses of 18% and 22% were observed for FCF and NFCF, respectively. FCF retained over 90% of iron, while zinc content remained constant. Losses of thiamin (27 to 39%) and riboflavin (37%) were produced during the process to convert corn masa flour into tortillas. CONCLUSIONS: Storage time slightly affected the stability of riboflavin and thiamin in FCF while the cooking process produced considerable losses of both vitamins. Tortillas made from FCF were well accepted by Mexican adults. We conclude that the addition of vitamins and minerals in the forms and quantities used in this study do not modify the shelf-life of corn flour, and neither do they cause sensorial changes in tortillas made from FCF.