Quality Parameters of Masa and Tortillas Produced from Blue Maize (Zea mays sp. mays) Landraces.

There is increasing interest in the production of landrace blue maize varieties for the production of traditional foods and for specialty (noncommodity) products. Most varieties have soft (floury) endosperm and their suitability for thermo-alkaline processing is not known. We examined the physical and functional properties of eight floury varieties with those of three dent and one flint variety for masa and tortilla production. Results revealed high variability in physical properties of kernels. Significant differences (P < 0.05) were observed in kernel, flour, masa, and tortilla color. The softer kernels of blue maize varieties had lower (P < 0.05) cooking times during nixtamalization than those of denser kernels. The results showed variation among varieties (P < 0.05) in the kernel, masa, tortilla hardness, as well as in extensibility of the tortillas. Nixtamalization affected (P < 0.05) masa color, resulting in reduced yellow and reddish tones. The gelatinization temperature was the same (P > 0.05) in all studied landraces for the flour and the masa. The enthalpy was affected (P < 0.05) by the landrace analyzed for starch gelatinization (P > 0.05). The landraces studied showed similar (P > 0.05) starch gelatinization and denaturation temperatures. The storage modulus (G'), loss modulus (G''), and the temperature (TG') of flour and masa-dough were different (P < 0.05) among different varieties. Southwestern floury varieties can be cooked during nixtamalization for shorter periods than flint and dent varieties to obtain comparable tortilla quality. PRACTICAL APPLICATION: Southwestern blue floury maize varieties are suitable for nixtamalized tortilla production. Variation between varieties was observed for quality parameters. Floury varieties require shorter cooking time but it is recommended that nixtamalization parameters be optimized.