Juan de Dios Figueroa Cárdenas

Nutritional quality of nixtamal tortillas fortified with vitamins and soy proteins

The nutritional qualities of nixtamal tortillas (TN) fortified with vitamins and soy flour was evaluated. The rats fed with TN and nixtamal tortillas with 0.15% of vitamins and iron (TNV) did not show differences in weights. The diets of fortified tortillas with 4% defatted soy (TNS), the combination of defatted soy and vitamins (TNVS) and the whole tortilla with defatted soy (TIS) were the treatments that caused the best growth in the experimental animals. The chemical analysis indicated appropriate levels of vitamins in the TNV, TNVS, TNS, and TIS diets. However, the TNV diet caused poor growth of the experimental animals. The diets of tortillas fortified with soy in general produced rats with longer femurs of greater density and strength. The rats fed with fortified tortillas showed higher levels of calcium and phosphorous in the bones. The X-ray diffractograms of bone tissue showed crystals with interplanar distances of 4.40, 3.34, 2.79, 2.28, 1.95, 1.85 and 1.45 Å, which are characteristic of hydroxylapatite, except for the first two measurements. The peaks at 4.40 and 3.34 Å tend to disappear as the nutritional quality of the diet improves with the addition of soy flour.

Nixtamalization Process Affects Resistant Starch Formation and Glycemic Index of Tamales

Tamales were prepared with 3 nixtamalization processes (traditional, ecological, and classic) and evaluated for chemical composition, starch properties, and glycemic index. Resistant starch (RS) in tamales increased 1.6 to 3.7 times compared to raw maize. This increment was due to the starch retrogradation (RS3) and amylose-lipid complexes (RS5) formation. Tamales elaborated with classic and ecological nixtamalization processes exhibited the highest total, soluble and insoluble dietary fiber content, and the highest RS content and lower in vivo glycemic index compared to tamales elaborated with traditional nixtamalization process. Thermal properties of tamales showed 3 endotherms: amylopectin retrogradation (42.7 to 66.6 °C), melting of amylose lipid complex type I (78.8 to 105.4), and melting of amylose-lipid complex type II (110.7 to 129.7). Raw maize exhibited X-ray diffraction pattern type A, after nixtamalization and cooking of tamales it changed to V-type polymorph structure, due to amylose-lipid complexes formation. Tamales from ecological nixtamalization processes could represent potential health benefits associated with the reduction on blood glucose response after consumption.

Creep Recovery of Wet Gluten and High-Molecular-Weight Glutenin Subunit Composition: Relationship with Viscoelasticity of Dough and Breadmaking Quality of Hard Red Winter Wheat

Effects of high-molecular-weight glutenin subunits on viscoelasticity of wet gluten, and its relationships with mixing, extensibility, and breadmaking parameters, were investigated by creep recovery using the Kelvin–Voigt model on 19 hard red winter wheat flours. Gluten samples with Glu-A1 1 and 2* showed significant differences in retardation time (λ2), whereas subunit 17+18 in Glu-B1 showed higher elastic moduli (G0, G1, and G2) and viscosity coefficients (η0, η1, and η2) compared with subunits 7+8 and 7+9. Wheats with Glu-D1 5+10 had higher values of G0, G1, G2, η0, η1, and η2 compared with Glu-D1 2+12. Gluten samples were on average 5.5, 3.1, and 1.6 times less stiff than dough when comparing G0, G1, and G2, respectively; these differences suggest that the nongluten components have high influence in the instantaneous and first Kelvin–Voigt elements of the model, and they are manifested more quickly compared with gluten components. Higher explanation of variance of loaf volume was found in parameters η...