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     

Effect of added calcium hydroxide during corn nixtamalization on acrylamide content in tortilla chips

This study has analyzed the influence of lime (Ca(OH)₂) concentration used during nixtamalization process on the physicochemical properties of nixtamalized corn flours and its effect on the acrylamide content in tortilla chips prepared from them. Flours prepared from nixtamalized corn with 0.5 and 1.0 g/100 g of Ca(OH)₂ showed higher levels of insoluble fiber, lower concentrations of calcium and ash, and a pH close to neutral. The acrylamide content of tortilla chips was correlated with the physicochemical properties of the flours. The results showed that acrylamide content was mainly affected by the ash, calcium, soluble fiber concentration in flour, as well pH value (p < 0.05). In comparison with tortilla chips made of flours prepared from nixtamalized corn with lime concentration of 1.0 g/100 g, a reduction of 52 and 36% in acrylamide content in tortilla chips made with flours prepared from nixtamalized corn with lime concentrations of 1.5 and 2.0 g/100 g, was obtained. The results suggest that controlling the concentration of Ca(OH)₂ during nixtamalization process can be used as an effective strategy for reducing acrylamide formation in fried products produced from nixtamalized corn flour.     

Effect of Defatted Soybean and Soybean Isolate Fortification on the Nutritional, Physical, Chemical and Sensory Properties of Wheat Flour Tortillas

Wheat flour fortified with 11.1% defatted soybean meal (SBM) or 5.6% soybean isolate (SBI) was processed into flour tortillas. Fortified tortillas contained 35% more protein and twice as much lysine as the 100% wheat flour tortilla. Addition of SBM or SBI decreased dough elasticity but increased dough water absorption and the force required to stretch the dough. The SBM fortified tortilla had better texture (P < 0.05) than the 100% wheat flour tortilla and similar flavor and color (P > 0.05). Rats fed fortified tortillas gained three times as much weight and doubled the protein efficiency ratio (PER) when compared to rats fed wheat flour tortillas. The apparent biological and net protein utilization values of the fortified tortillas were similar (P > 0.05) and higher (P < 0.05) than the wheat flour tortilla. The SBI fortified tortilla had a higher apparent protein digestibility (P < 0.05) than the 100% wheat flour and SBM fortified tortillas.     

Formulation,Evaluation and Optimization of Tortillas Containing Wheat,Cowpea and Peanut Flours Using Mixture Response Surface Methodology1

The performance characteristics of tortillas, prepared with different composite blends of wheat, cowpea and peanut flours, were evaluated by mixture response surface methodology. Optimum wheat flour substitution levels were determined. Results indicated that wheat flour could be successfully replaced with up to 24% cowpea and 46% defatted peanut flours and result in tortillas with quality characteristics comparable to those from 100% wheat. Sensory evaluation indicated that beany flavor was the most limiting attribute. Sensory attributes correlated significantly with physical and compositional measures of tortillas and physical measures of tortilla dough.     

Compositional and varietal influence of finger millet flour on rheological properties of dough and quality of biscuit

Biscuits prepared from flour composites containing 60:40 and 70:30 (w/w) finger millet:wheat flour were evaluated for its dough characteristics and biscuit quality. Hardness of biscuit dough measured by textural profile analysis was more in 60:40 combination than in 70:30 level. The dough became more adhesive with higher level of wheat flour and it varied across varieties. Extensograph data also showed that resistance of biscuit dough increased with the increasing levels of wheat flour. However, very little difference was observed between addition of 30 and 40 g/100 g wheat flour in terms of resistance to extension. Wheat composite flour (40 g/100 g) had higher water absorption capacity than in 30 g/100 g composite flour. Bandwidth of composite flour was narrower in 40 g/100 g wheat flour composite. Expansion of biscuit and breaking strength after baking was more in 70:30 composite than in 60:40. Among the varieties used, VL-324 brought about the positive changes of composite flour in rheological characteristics in terms of adhesiveness, extensibility and resistance to extension, which in turn improves biscuit quality. It provided better physical quality biscuit dough and biscuit in terms of its spread ratio, density and breaking strength. Studies indicated that composite of finger millet and wheat flour (60:40) was found better, particularly in case of biscuit quality. Out of six varieties, VL-324 was found best in terms of biscuit quality as well as acceptability.     

Development of extruded snacks using taro (Colocasia esculenta) and nixtamalized maize (Zea mays) flour blends

Extruded snacks were prepared from flour blends made with taro and nixtamalized (TF-NMF) or non-nixtamalized maize (TF-MF) using a single-screw extruder. A central composite design was used to investigate the effects of taro flour proportion in formulations (0-100 g/100 g) and extrusion temperatures (140-180 °C) on the following indices: expansion (EI), water solubility (WSI), water absorption (WAI) and fat absorption (FAI). Moreover, selected TF-NMF and TF-MF extruded products were partially characterized through proximate chemical analysis, resistant starch, color, pH, water activity, apparent density, hardness, and sensory analysis. Results indicated that EI and WSI of both TF-MF and TF-NMF extrudates were significantly increased by the use of higher proportions of taro flour, while the opposite behavior was observed for the FAI (p < 0.05). Taro flour at higher proportions in both extrudates did not produce a significant change of WAI, while the use of higher extrusion temperatures only caused a significant increase of FAI in TF-MF extrudates (p < 0.05). This study showed that flour mixtures made from taro and nixtamalized maize flour produced puffed extruded snacks with good consumer acceptance.     

Physicochemical and Sensory Properties of Corn Tortillas Made from Nixtamalized Corn Flour Fortified with Spent Soymilk Residue (okara)

ABSTRACT: The chemical study of okara composition and a sensory evaluation study were conducted to determine the effect of okara supplementation on certain physical, chemical and sensory properties of corn tortilla. Dried okara was added at the level of 5,10,15,20, and 25% to nixtamalized corn flour. Due to flavor, enriched tortillas at levels higher than 10% of okara were not accepted. At 10% of okara supplement, lysine and tryptophan content in tortilla were increased from 56 and 70% of FAO profile to 93 and 92% respectively.     

Characteristics of nixtamalised maize flours produced with the use of microwave heating during alkaline cooking

Whole, ground and abrasively dehulled grains from both normal (H‐34 and H‐34) and quality protein (QPM and QPMa) maize were mixed with water contents of 70, 95 and 100 g kg⁻¹ and calcium hydroxide concentrations of 0.0, 0.3, 0.5 and 2.0 g kg⁻¹ and heated (operating frequency 2.450 MHz, high‐power setting) for 10, 15 and 20 min in a commercial microwave oven. The cooked grain was then oven dried and milled to obtain nixtamalised maize flour (NMF). The protein contents and test weights of QPM were higher than for the normal hybrids. The highest yields of masa and tortillas were found for the normal hybrids, and these samples did not show significant differences, as compared with the commercial nixtamalised flour (CNMF) used as control, with respect to masa firmness and adhesiveness and tortilla tensile strength. The cutting force of tortillas from hybrid H‐30 and QPM did not show significant differences from the control. The highest values of tortilla rollability were found for the control followed by hybrid H‐34. The values of residual cooking liquor for microwave‐heated samples were lower than for the control. Ground or dehulled maize grain gave sticky masa and poor mechinical characteristics. Tortillas from whole grain showed good characteristics of texture and consistency of masa, and the tortillas were subjectively similar in colour, flavour and rollability to the tortillas prepared with CNMF. These results indicate a potential use of microwave energy to produce NMF for tortillas and derivatives. © 2000 Society of Chemical Industry     

MOLD INHIBITION IN TORTILLA BY DIMETHYL FUMARATE

Nine batches of tortilla containing 0, 0.05, 0.1., 0.2 and 0.4 g of calcium propionate or dimethyl fumarate per 100 g corn flour were prepared. The tortillas were individually packaged in polyethylene bags, stored at room temperature and observed daily for visible signs of mold growth. Samples from each batch were also subjected to the determination of moisture and water activity. The mold-free shelf-lives of tortillas containing calcium propionate ranged from 2–5 days and those of tortillas containing dimethyl fumarate ranged from 2–11 days.     

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.     

Effect of buckwheat flour addition to wheat flour on acylglycerols and fatty acids composition and rheology properties

In this paper, the rheological properties and lipids composition with an emphasis on acylglycerols and fatty acids composition of dough with various portions of buckwheat flour (BWF) are investigated. The results show lipids from wheat-buckwheat flour mixture has higher ratio of total unsaturated to saturated fatty acids content (3.77-4.78 g/100 g) than those of wheat flour only (3.71 g/100 g). The value of dough water absorption (WA), development time (DT), dough stability (DSt), gelatinization temperature (T_max) and maximal pasta viscosity (η_max) increases when content of free fatty (FFA) acids increases, i.e. when buckwheat flour portion in flour mixtures increases, so FFA content has a proper influence on these dough properties. Dough with buckwheat flour has higher WA (54.3-56.0 ml/100 g), T_max (82.0-84.1 °C) and η_max (630-860 AU), longer Dst (0.7-4.6 min) and lower Dsf (82-90 FU) than dough with wheat flour only, whose appropriate values are 54.3 ml/100 g, 81.2 °C, 480 AU, 0.3 min and 90 FU, respectively. So, the flour mixture with buckwheat flour of at least 5 g/100 g can be considered good quality flour.     

Effects of common bean enrichment on nutritional quality of tortillas produced from nixtamalized regular and quality protein maize flours

In Mexico the tortilla is most commonly eaten in the form of ‘taco’; this is normally accompanied with other food, in particular the common bean. Tortillas made of quality protein maize (QPM) fortified with common bean might be a strategy to improve their protein quality. In this study, amino acids and mineral changes that occur during nixtamalization and the chemical and nutritional characteristics of regular, commercial and QPM tortilla–bean combination were assessed. After nixtamalization, protein from QPM nixtamalized maize flour was reduced from 8.1% to 7.2% (w/w). Tryptophan was also reduced from 12.1 to 11.1 g kg^?1 protein. QPM maize retained a higher amount (P < 0.05) of calcium (3180 mg kg^?1) compared to regular maize (1820 mg kg^?1). When nixtamalized maize flour of regular maize and commercial tortilla were combined with beans, protein content increased. The tryptophan and lysine contents in these tortillas were increased (P > 0.05) also, but were significantly lower (P > 0.05) than in tortilla made with QPM maize fortified with bean (22.7 and 69.9 g kg^?1 protein, respectively). Mineral contents increased in tortilla–bean combination. The QPM and tortilla fortified with bean gave an improvement in protein quality and could contribute significantly towards human nutrition, especially in countries like Mexico where maize and beans are important components of the diet. 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.     

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.     

In vitro starch digestibility changes during storage of maize flour tortillas

Nixtamalized maize flours elaborated by four factories in Mexico were used for tortilla preparation. Samples were stored at 4 degrees C for up to 72 h and their in vitro starch digestibility features were evaluated. Moisture content was different between flour and tortilla but no evident relation could be established. Protein and lipid levels were lower in tortillas than in flour but ash content was not different in both samples. A decrease in available starch content was observed upon 48 h cold storage (4 degrees C), changes that were concomitant with increased total resistant starch (RS) levels. These changes were due mainly to retrogradation, as suggested by the increased retrograded resistant starch (RRS) levels recorded in stored tortillas; in some samples, RRS represented up to 100% of total RS. The digestion (alpha-amylolysis) rate (DR) of freshly prepared tortillas differed for the various samples. Although the amylolysis patterns for fresh and 72 h-stored tortillas were similar, lower DR values were shown for the stored materials. The differences found among the various tortilla samples may be due to variations in processing conditions during commercial maize flour preparation, and to the use of different maize varieties.     

Nixtamalisation of maize (Zea mays L) using a single screw cook-extrusion process on lime-treated grits

The tortilla flour market is expanding but present industrial production is lagging behind in the use of modern technologies to increase production and cut costs due to the maize steeping and drying operations. A process using a single-screw cook-extruder which eliminates the traditional steeping and drying operations was therefore explored. Lime (Ca(OH)₂) suspension was absorbed onto commercial maize grits (2 g lime kg^?1 maize) and the resulting meal conditioned to various moisture contents. These samples and one which had not been lime-treated were cook-extruded through a Brabender Do-corder extrusion cooker (Type 825602). The dry extrudate was milled through a 150 μm sieve and tortillas made from each sample. The tortillas prepared from the lime-treated grits conditioned to 472 g kg^?1 moisture compared favourably with that prepared from traditionally prepared masa flour when organoleptically assessed. Flour pasting properties (viscosity) and water absorption index were not significantly different (P < 0.05) from the traditionally prepared products. Enzyme susceptible starch index did not correlate well with dough quality.     

Nixtamalised flour and tortillas from transgenic maize (Zea mays L.) expressing amarantin: Technological and nutritional properties

Nixtamalised flour from transgenic maize (genetically modified maize with the cDNA of amarantin) and its tortillas were evaluated for some technological and nutritional properties and compared to the commercial brand MASECA^™. Nixtamalised transgenic maize flour (NTMF) showed higher protein content, total colour difference, pH, water solubility index, essential amino acids content and lower Hunter “L” value, water absorption index, resistant starch and retrograded resistant starch than MASECA^™ flour. Tortillas from NTMF had higher protein content (12.64% vs 8.93%, db), essential amino acids content and calculated protein efficiency ratio (C-PER; 2.05 vs 1.04) than tortillas from MASECA^™. Tortillas from both nixtamalised transgenic maize and MASECA^™ flours showed similar sensory properties (puffing and acceptability). The use of transgenic maize for flour and tortilla preparation may have a positive impact on the nutritional status of people from countries where maize is the basic staple food.     

The optimization of the extrusion process when using maize flour with a modified amino acid profile for making tortillas

Maize with a modified amino acid profile, i.e. greater amounts of lysine and tryptophan than normal, is known as ‘quality protein maize’ (QPM). The objective of this work was to find the best combination of extrusion process variables to produce QPM flour for making tortillas. QPM grits were mixed with lime and water and had a moisture content of 28%. The single screw extruder operation conditions were selected from factorial combination of three process variables: extrusion temperature (ET, 70–100 °C), lime concentration (LC, 0.1–0.3% of the maize weight) and screw velocity (SV, 80–250 rpm). Response surface methodology was used as an optimization technique. In vitro protein digestibility (PD); total colour difference (ΔE) of the flours, and tortilla puffing (TP) were chosen as response variables. A graphical method was used to obtain maximum PD, TP and minimum ΔE. The optimum combination of process variables was: ET = 85 °C/LC = 0.21%(w/w)/SV = 240 rpm. Tortillas from QPM flour had similar chemical composition, physicochemical and sensory properties to tortillas from commercial nixtamalized maize flour; however, the former had the highest (P ≤ 0.05) available lysine content and were therefore better nutritionally.     

Effect of flaxseed flour addition on physicochemical and sensory properties of functional bread

The importance of polyunsaturated fatty acids (PUFA) in health and nutrition is well recognised. Flaxseed (Linum usitatissimum) has recently gained a lot of attention as functional food because of its unique nutrient profile. In the present work efforts were made to develop omega-3 enriched functional bread using raw and roasted ground flaxseed flour. Initially optimisation of each bread ingredient viz., salt, sugar, and shortening, GMS, yeast and water was carried out on the basis of sensory overall acceptability score. The standardised bread was incorporated with raw and roasted ground flaxseed (5, 10, and 15 g/100 g) flour. The effect of flaxseed incorporation on bread dough rheology parameters viz., dough stickiness and water absorption was studied. Increase in water absorption and dough stickiness was observed with increased flaxseed level. Further breads were evaluated for sensory parameters, colour and texture. The crumb softness increased with increase in flaxseed level. Bread was optimised at 10(g/100 g) flaxseed level based on sensory evaluation.     

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.