Physicochemical and nutritional properties of different maize races on toasted tortillas

Abstract

Biodiversity contributes to nutrient production and, together with processing, is a critical factor in product quality. Physicochemical and nutritional properties of toasted tortillas (totopos) were evaluated in 1) maize samples from Oaxaca communities and 2) maize races of different endosperm texture. Texture profiles show that totopos elaborated from Zapalote Chico maize race showed the best performance (low breaking force) and higher crunchability, similar to commercial totopos. Quality of Zapalote Chico totopos was explained by flotation index (FI) and starch viscosity as well as thermal properties. FI was negatively correlated with texture that may related to end use. Zapalote Chico maize gelatinizes at higher (P < 0.05) pasting temperature (72.8-73.3°C) and it had higher (P > 0.05) peak viscosity (3,093-4,723 cP), suggesting a more organized starch structure. In hybrid and Tuxpeno samples, most of the starch granules (90%) were gelatinized and increased the hardness in totopos. The totopo samples increased the peak at 4.45 A, a characteristic ° of type-V diffraction of amylose-lipid complexes (resistant starch). A small increase in resistant starch (0.6%) was found in totopos, which has important nutritional benefits for consumers. Our results support the preference of Oaxaca people for the totopos made from Zapalote Chico maize.