Effect of Different Amounts Amino Acid Combined with Dry-heat Treatment on Physicochemical and Digestive Properties of Common Corn Starch

Abstract

Corn starch was modified by dry heat treatment combined with amino acids (aspartic acid and lysine) in the present research. Gelatinization, thermal, structural, and digestive properties of dry heat-treated corn starch with different amount of amino acids were investigated by using Rapid Viscosity Analyser, differential scanning calorimetry, and X-ray diffractometry. The results indicated that the amount of amino acids showed significant effects on the physicochemical properties and digestive properties of dry heat-treated corn starch-amino acid mixtures. With increasing the addition of amino acids, peak viscosity, setback value, and gelatinization enthalpy of starch decreased, while relative crystallinity and resistant starch content increased. Gelatinization temperature of dry heat-treated corn starch-aspartic acid mixtures showed a tendency to increase first and then decrease with increasing the amount of aspartic acid. However, gelatinization temperature of dry heat-treated corn starch-lysine mixtures increased with increasing the amount of lysine. Increasing the amount of amino acids also promoted a tighter and more ordered crystal arrangement inside starch granules, which could inhibit the short-term retrogradation and reduce the digestibility of starch. This study can be used as a new method for corn starch modification and provide a reference for the production of modified starch.

Keywords

• lysine
• aspartic acid
• corn starch
• dry-heat treatment
• physicochemical properties
• digestive properties