AMYLOSE:AMYLOPECTIN RATIO IN STARCH OF NIXTAMALIZED MAIZE FLOUR AND ITS RELATIONSHIP WITH TORTILLA QUALITY

Abstract

The modification of amylose:amylopectin (AML:AMP) ratio in starch of nixtamalized maize flour was evaluated on the flour rheological properties and tortilla quality. Four amylose:amylopectin ratios (15:85, 20:80, 40:60, and 50:50) were tested in two commercial nixtamalized corn flours, plus in another flour prepared under the traditional nixtamalization method. Physical and chemical characteristics were determined on the three fluors. The quality of tortillas prepared with the flours having different amylose:amylopectin ratios were evaluated in terms of color, texture and humidity during a five day storage period at 4±1 °C. The amylograms from flours with high amylose ratio displayed high initial gelatinization temperature (TIG), low viscosity development and absence of the maximum viscosity peak. Tortillas prepared from flours with high amylose ratio showed a sharp decrease in moisture content and a high increase in hardness during storage. Tortillas from high amylopectin treatments showed only slight changes in moisture content and softness during storage, while tortillas obtained from high amylose flours showed a brighter color than those obtained from high amylopectin flours.