Corn Tortillas Research Articles

Nutritive value of selected variety breads and pastas

Nine types of commercially produced variety breads, plain bagels, corn tortillas, and three types of pasta products were obtained from each of four cities, New York, San Francisco, Atlanta, and Kansas City. Proximate components and 12 minerals and vitamins were determined in these and in cooked pasta products. Available carbohydrate and energy values were calculated. On the average, French, Italian, and pita breads were lower in moisture than other breads. Protein in bread products averaged between 7.6% and 10.4% and in cooked pastas and tortillas between 4.4% and 5.3%. Bagels averaged 10.2% protein. Insoluble dietary fiber in whole wheat bread averaged 5.6%; for most products, dietary fiber values were five- to eightfold higher than crude fiber values. Pasta products and tortillas were virtually free of sodium. Sodium in bread products averaged between 379 and 689 mg/100 gm. Although all pasta products and most bread products were enriched, calcium was often not included. Iron averaged from 2.16 to 3.29 mg/100 gm in bread products and 3.10 to 4.24 mg/100 gm in dry pasta products. Products made with unrefined or less-refined flours and/or containing germ and bran tended to be high in phosphorus, magnesium, zinc, and manganese, and, to a lesser extent, in copper. A good portion of potassium, thiamin, riboflavin, and niacin in pasta products was lost during cooking.

Sensory Attributes of Corn Tortillas with Substitutions of Potato, Rice, and Pinto Beans

ABSTRACTCorn tortillas were prepared with substitutions of 12, 24, and 36% of two varieties of potato, 10, 20, and 30% of rice, and 5, 10, and 15% of pinto beans. Trained judges developed descriptors for appearance, aroma, manual and oral texture, flavor, and aftereffects, to quantify differences from the all‐corn reference. Up to 24% of either variety of potato, 30% of rice, and 15% beans could be substituted before undesirable sensory differences were detected. Potato improved texture, producing a softer, more flexible tortilla. Beans produced a less yellow, harder tortilla, and rice caused few sensory changes. Sensory texture compared well with Instron hardness and elongation measurements. Protein and lysine were unchanged by potato, increased by bean, and slightly decreased by rice substitution.

THE INFLUENCE OF MAILLARD BROWNING AND OTHER FACTORS ON THE STABILITY OF FREE TRYPTOPHAN

The influence of various factors on the stability of free tryptophan was evaluated in several reaction systems. After treatment, tryptophan was measured by high performance liquid chromatography. Factors such as heating, protein, and glucose were responsible for tryptophan losses in a system undergoing Maillard browning. Hydrogen peroxide caused extensive losses while pH and light had minimal effect on tryptophan stability in solution. When the stability of tryptophan was compared to lysine and threonine during browning, threonine had the highest retention. At low water activity (0.22), tryptophan had the lowest retention (42%) while at a high water activity (0.75) lysine had the lowest retention (5%). When fortified corn tortillas were made using the typical heat treatment involved in preparation, retention of added lysine and tryptophan was 85–90%.

Effect of fiber in corn tortillas and cooked beans on iron availability.

Effect of fiber in corn tortillas and cooked beans on iron availability.

TORTILLA‐MAKING CHARACTERISTICS OF MICRONIZED SORGHUM AND CORN FLOURS

ABSTRACTMicronizing is a dry heat process using gas fired infra‐red burners to heat. grain almost to the point of eversion followed by rolling through corrugated steel rollers. Various levels of micronized pearled sorghum (MPS) were substituted for commercial corn tortilla flour. 20% of MPS produced tortillas with acceptable color, flavor, and texture. Pliability of the dough was enhanced due to greater water absorption of MPS. Micronized corn tortillas, texture and rollability compared well to tortillas from a commercial corn tortilla flour and from white corn. Alkali added to the micronized corn increased yellowness, pH, and flavor with a simultaneous darkening. In a 5‐day storage study, commercial corn flour tortillas deteriorated in quality rapidly. Storage at 37° C kept the micronized corn and traditional tortillas more flexible than storage at room temperature.

Iron, thiamin, riboflavin, and niacin content of corn tortillas made in Los Angeles, California

Corn tortillas are a common food in the diet of people of Mexican descent who live in the Los Angeles area. Corn tortillas are not enriched, and on a weight basis contain less iron, thiamin, ribofl...

SORGHUM TORTILLAS: PROCESS AND PRODUCT ATTRIBUTES

ABSTRACTTortillas were made from different sorghum types, employing the basic process for making corn tortillas. A textural comparison study between corn and intermediate endosperm sorghum tortillas was conducted employing tensile testing methods using an Instron Universal Testing Machine. Corneous and intermediate endosperm sorghum grains were found to produce tortillas similar to those made from corn, although processing conditions of time, temperature, and lime dose required to give acceptable tortillas were varied. The corneous textured endosperm produced sorghum tortillas having grainy characteristics not exhibited by the intermediate endosperm product. Sorghum tortillas became darker when higher doses of lime were added, and dilute citric acid was used to achieve pH change during grain neutralization. Greater tensile strength and stretchability were observed in the intermediate endosperm sorghum tortillas than in the corn product, indicating greater flexibility and possible reliability. No significant difference was found between the acceptability of intermediate endosperm sorghum and corn tortillas. Sorghum tortillas had greater protein content than corn tortillas.

SIMULTANEOUS PRODUCTION OF PENICILLIC ACID AND PATULIN BY A Penicillium SPECIES ISOLATED FROM CHEDDAR CHEESE

ABSTRACTA Penicillium sp. isolated from Cheddar cheese and tentatively identified as an atypical strain of Penicillium roqueforti was found to produce penicillic acid and patulin simultaneously. This study was done to determine the effects of substrate, incubation temperature and time on the ratio and quantities of toxins produced. Three substrates known to support mycotoxin production (yeast‐extract sucrose, potato‐dextrose and Raulin‐Thom broths), a medium containing lactose and casein, several foods (Cheddar cheese, Swiss cheese, sausage, cooked cornmeal, yellow dent corn and corn tortillas), and a shredded wheatnutrient broth medium known to support toxin production were used as substrates. Incubation temperatures of 5, 12 and 25°C were studied over several periods of time for each group of substrates. Of all the substrates studied, the broth substrates previously known to support mycotoxin production supported the most abundant toxin production under all conditions. The greatest concentrations of toxins were produced at 12°C followed by 5°C. The lowest quantities of both mycotoxins were produced at 25°C regardless of substrate. Patulin was produced predominately on potato‐dextrose broth, both penicillic acid and patulin were produced on yeast extract‐sucrose broth, and penicillic acid was predominately produced on Raulin‐Thom broth. Neither toxin was produced on Cheddar cheese, Swiss cheese, summer sausauge or corn tortillas, but penicillic acid was produced on cooked cornmeal and both penicillic acid and patulin were produced on yellow dent corn, with best production occurring at 12°C. Substrates low in carbohydrate did not support appreciable levels of mycotoxin production.

FACTORS AFFECTING COLOR AND APPEARANCE OF CORN TORTILLAS

ABSTRACT.A study is described which examined the relative contributions of production and post‐production variables on color and appearance of corn tortillas. Tortillas processed at three production sites were stored under exact marketing conditions in refrigerated display cases in three supermarkets. Reflectance measurements and visual evaluations immediately on delivery showed that processing variables contributed heavily to initial appearance and color differences. Rate of appearance deterioration on storage was affected by both processing and storage variables. The rate and magnitude of visually perceived changes on storage was not paralleled by a similar rate and magnitude of change in diffuse reflectance characteristics. This suggests that the visually perceived changes were due to structural rather than color changes.

UTILIZATION OF WHOLE UNDEFATTED GLANDLESS COTTONSEED KERNELS AND SOYBEANS TO PROTEIN‐FORTIFY CORN TORTILLAS

ABSTRACTTortillas have long been recognized as the ideal vehicle for fortification to upgrade the nutritional status of peoples of the South and Southwest where tortillas are widely consumed. In previous work reported by the same authors, oilseed flours were used to protein‐fortify corn flour used for the preparation of corn tortillas. In this work, we have found that tortillas can be protein‐fortified by utilizing the traditional means of preparation and incorporating blends of undefatted glandless cottonseed kernels and soybeans with corn in sufficient quantities to provide a total of 12%, 15% and 18% protein in the blends. This provided a significant protein increase from 10.5% protein in the corn control to a maximum of 18% protein in the blends on a dry basis ‐ a 42% increase in protein. Higher protein blends could not be successfully prepared with glandless cottonseed kernels because the increased oil became an objectionable factor. A dough preparation technique was developed which yielded fortified doughs that compared favorably with the corn control. In color comparisons made with a Hunter color‐difference meter, 12% protein blend tortillas were comparable in color with the corn control. As the amount of oilseed increased in the protein blend above 12%, the color of the cooked tortillas increased as well. Ammo acid profiles of the cooked tortillas indicated that there is an increase in both the quality and quantity of protein when glandless cottonseed kernels and soybeans are utilized in blends with corn for making corn tortillas. Tortillas containing the different blends were submitted to a taste panel for sensory evaluation and the scores obtained were statistically analyzed. When all protein levels of a particular oilseed were considered together, at both 1% and 5% level of significance, taste panel members expressed no difference in overall satisfaction from the corn as compared to cottonseed‐fortified tortillas. Furthermore both the control and cottonseed‐fortified tortillas were preferred to soy or blend‐fortified tortillas.

EVALUATION OF CORN TORTILLAS SUPPLEMENTED WITH COTTONSEED FLOUR

ABSTRACTThe nutritional value of corn tortillas was substantially improved when supplemented with cottonseed flour (CSF) as noted by amino acid analysis and rat growth studies. This is probably attributable to improved contents of lysine and tryptophan. The leucine‐isoleucine ratio also was improved. Rats showed the greatest weight gain from tortillas supplemented with 20 and 25% CSF. Protein efficiency ratio and net protein ratio values of the latter were not significantly different than those of casein. Tortillas supplemented with CSF showed an improved shelf life as noted by lower fat acidity values. There were no significant differences in acceptability of the supplemented tortillas.

PROTEIN FORTIFICATION OF CORN TORTILLAS WITH OILSEED FLOURS

ABSTRACTIn work performed at the Food Protein R&D Center, three oilseed flours‐deglanded liquid cyclone process (LCP) cottonseed flour, glandless cottonseed flour, and a high nitrogen solubility soy flour were used to fortify corn tortillas. Tortillas containing each of these flours blended with a corn tortilla flour to give 11%, 13%, and 15% protein in the blends were statistically compared in sensory tests for flavor, texture, and overall acceptability. An analysis of variance performed on panel scores indicated that the panel had no preference among the corn control tortillas and tortillas fortified with LCP and glandless cottonseed flours. The panel did, however, show a significant preference for each of these tortillas over soy‐fortified tortillas. In color comparisons made with a Hunter Color‐Difference meter, tortillas fortified with deglanded LCP cottonseed flour were increased in color over that of tortillas fortified with the other flours at the 11% protein level. As the amount of oilseed flours increased above the 11% blend level, the color of tortillas fortified with glandless and LCP increased noticeably. However, the color of soy‐fortified tortillas essentially remained the same. Fortification of tortillas at the 11%, 13% and 15% blend levels increased the total protein by 18%, 40% and 61%, respectively. These tests indicated that protein‐enriched tortillas can be prepared using oilseed flours.

ENRICHMENT OF TORTILLAS WITH SOY PROTEINS BY LIME COOKING OF WHOLE RAW CORN‐SOYBEAN MIXTURES

A simple and inexpensive method for enriching tortillas with soy proteins was studied. The method consisted of application of the traditional process for making corn tortillas to whole raw corn‐soybean mixtures: lime cooking of a mixture, allowing the cooked mixture to stand overnight in the cooking liquor, washing the mixture with tap water, grinding the cooked mixture into a dough, and making tortillas from the dough. This method of enrichment was found to give tortillas with significantly higher protein content and protein quality than normal un‐enriched tortillas. PER and NPU values of tortillas containing 8% and 16% soya were found to be comparable to those obtained with tortillas enriched with soy flour or with amino acids lysine and tryptophane. The presence of soybeans in tortillas so enriched was found to be not significantly detectable by a trained panel, at least up to a soya level of 16%. Toxic factors present in raw soybeans were not detected in enriched tortillas by the urease method, having been apparently inactivated by the tortilla‐making process. Enrichment by this method is cheaper than enrichment with soy flour or with amino acids. The method permits uniform introduction of soya proteins within the tortillas, and changes neither food recipes nor eating habits.