Effects of soybean fortification on protein quality of tortilla-based diets produced from regular and quality protein maize

Physicochemical, thermal, and rheological properties of nixtamalized blue-corn flours and masas added with huitlacoche (Ustilago maydis) paste

The aim of this work was to evaluate the effect of the addition of huitlacoche paste to nixtamalized blue-corn flours (NBCF) on the physicochemical, thermal, and rheological properties of masas. Raw blue maize was nixtamalized (hydrothermal alkalinized process), then was wet-milled in a stone mill, masa was dehydrated, pulverized and sieved to obtain NBCF; commercial nixtamalized blue-corn flour (CNBCF) was used as a control. Huitlacoche paste in concentrations of 3, 6, 9, 12, 15, and 18% was added to nixtamalized flours. Characteristics of the blue grain showed its great effects on water absorption, viscosity, and masa cohesiveness; the addition of huitlacoche significantly influenced adhesiveness, water-absorption, color, and the rheological properties (p < 0.05). Values between 0.03 and 0.083 kg-force resulted in masas with optimal adhesiveness. The inclusion of huitlacoche paste can be achieved with a maximal addition of 9% in NBCF for an industrial process and could comprise a new industrialization alternative.

In vivo protein quality of selected cereal-based staple foods enriched with soybean proteins

Background

One way to diminish protein malnutrition in children is by enriching cereal-based flours for the manufacturing of maize tortillas, wheat flour tortillas, and yeast-leavened breads, which are widely consumed among low socio-economic groups.

Objective

The aim was to determine and compare the essential amino acid (EAA) scores, protein digestibility corrected amino acid scores (PDCAAS), and in vivo protein quality (protein digestibility, protein efficiency ratio (PER), biological values (BV), and net protein utilization (NPU) values) of regular versus soybean-fortified maize tortillas, yeast-leavened bread, and wheat flour tortillas.

Design

To comparatively assess differences in protein quality among maize tortillas, wheat flour tortillas, and yeast-leavened breads, EAA compositions and in vivo studies with weanling rats were performed. The experimental diets based on regular or soybean-fortified food products were compared with a casein-based diet. Food intake, weight gains, PER, dry matter and protein digestibility, BV, NPU, and PDCAAS were assessed. The soybean-fortified tortillas contained 6% of defatted soybean flour, whereas the yeast-leavened bread flour contained 4.5% of soybean concentrate.

Results

The soybean-fortified tortillas and bread contained higher amounts of lysine and tryptophan, which improved their EAA scores and PDCAAS. Rats fed diets based on soybean-fortified maize or wheat tortillas gained considerably more weight and had better BV and NPU values compared with counterparts fed with respective regular products. As a result, fortified maize tortillas and wheat flour tortillas improved PER from 0.73 to 1.64 and 0.69 to 1.77, respectively. The PER improvement was not as evident in rats fed the enriched yeast-leavened bread because the formulation contained sugar that decreased lysine availability possibly to Maillard reactions.

Conclusions

The proposed enrichment of cereal-based foods with soybean proteins greatly improved PDCAAS, animal growth, nitrogen retention, and PER primarily in both maize and wheat flour tortillas. Therefore, these foods can help to diminish protein malnutrition among children who greatly depend on cereals as the main protein dietary source.

Chemical composition, starch digestibility and antioxidant capacity of tortilla made with a blend of quality protein maize and black bean

Tortilla and beans are the basic components in the diet of people in the urban and rural areas of Mexico. Quality protein maize is suggested for tortilla preparation because it presents an increase in lysine and tryptophan levels. Beans contain important amounts of dietary fiber. The objective of this study was to prepare tortilla with bean and assesses the chemical composition, starch digestibility and antioxidant capacity using a quality protein maize variety. Tortilla with bean had higher protein, ash, dietary fiber and resistant starch content, and lower digestible starch than control tortilla. The hydrolysis rate (60 to 50%) and the predicted glycemic index (88 to 80) of tortilla decreased with the addition of bean in the blend. Extractable polyphenols and proanthocyanidins were higher in the tortilla with bean than control tortilla. This pattern produced higher antioxidant capacity of tortilla with bean (17.6 μmol Trolox eq/g) than control tortilla (7.8 μmol Trolox eq/g). The addition of bean to tortilla modified the starch digestibility and antioxidant characteristics of tortilla, obtaining a product with nutraceutical characteristics.

Evaluation of the lime-cooking and tortilla making properties of quality protein maize hybrids grown in Mexico

Eleven experimental and three commercial white quality protein maize (QPM) hybrids and two regular endosperm controls were planted at Celaya, Guanajuato, Mexico with the aim of comparing grain physical characteristics, protein quality, lime-cooking and tortilla making properties. All genotypes were planted under irrigation using a density of 80,000 plants/ha and fertilized with 250 kg N-60 P-60 K per hectare. When compared with the controls these QPM genotypes had lower test (77.4 vs. 76.5 kg/hL) and 1,000 kernel weights (327 vs. 307 g), softer endosperm texture (2.5 vs. 1.8 where 1 = soft, 2 intermediate and 3 hard endosperm), lower protein (10.0 vs. 8.0%), higher nixtamal water uptake after 30 min lime-cooking (50.0 vs. 53.1% moisture) and lower pericarp removal scores. The lower thousand-kernel weight and softer endosperm texture observed in the QPM genotypes lowered the optimum lime-cooking time as estimated with regression equations. Most QPM genotypes had higher amounts of lysine, tryptophan and albumins/globulins when compared with the controls. QPMs HEC 424973, HEC 774986 and HEC 734286 had the best grain traits for nixtamalization and therefore the best potential for industrial utilization. The commercial use of these QPM hybrids should benefit Mexicans who depend on tortillas as the main staple.

Efeito da adição dietética de milho de alta qualidade protéica em camundongos

OBJETIVO: O objetivo do estudo consistiu em avaliar os efeitos da adição de milho quality protein maize BR473 sobre aspectos bioquímicos e fisiológicos. MÉTODOS: Camundongos Swiss, fêmeas, 6-7 semanas, foram alimentados com rações comerciais, rações comerciais com milho híbrido (1:1), rações comerciais com milho de alta qualidade protéica (1:1). Foram avaliados, durante 3 meses, o consumo de ração, o ganho de peso e de tecido adiposo retroperitoneal e os valores plasmáticos de proteínas, triglicerídeos, colesterol e glicose. RESULTADOS: A adição dietética de milho quality protein maize BR473 reduziu o consumo alimentar e o tecido adiposo retroperitoneal, porém manteve a glicemia e trigliceridemia em relação à adição de milho híbrido na ração comercial. CONCLUSÃO: A melhor eficiência alimentar e os impactos sobre os parâmetros bioquímicos do sangue sugerem o potencial do uso do milho quality protein maize BR473 como um importante complemento para garantir a segurança alimentar e nutricional.

Soyabean fortification and enrichment of regular and quality protein maize tortillas affects brain development and maze performance of rats

The brain development and performance of rats fed throughout two generations with an indigenous maize tortilla-based diet was studied. The experiment compared casein control with five different diets produced from: regular fresh masa; regular, enriched dry masa flour containing thiamin, riboflavin, niacin, folic acid, Fe and Zn (REDMF); dry masa flour fortified with 60 g/kg defatted soyabean meal and enriched (FEDMF); enriched quality protein maize (QPM) flour (EQPM); QPM flour fortified with 30 g/kg defatted soyabean meal and enriched (FEQPM). In both generations, brain and cerebellum weights and myelin concentration were significantly higher (P < 0.05) in rats fed the FEDMF and FEQPM diets. There was no significant difference (P > 0.05) in brain DNA in first-generation rats; however, second-generation rats fed FEDMF, EQPM and FEQPM tortillas had higher cerebral DNA, neuron size and brain activity as estimated by the RNA:DNA ratio. Short-term and long-term memory performance in the Morris maze improved (P < 0.05) among rats fed the FEDMF, FEQPM and EQPM diets. Second-generation rats fed the FEDMF and FEQPM diets had a superior (P < 0.05) working memory and learning performance. The utilisation of regular or QPM tortillas enriched with selected micronutrients and fortified with soyabean is highly recommended to assure adequate brain development. The high lysine-tryptophan QPM made it possible to save half of the soyabean flour without sacrificing the nutritional value of soyabean-fortified tortillas.