Preparation and Properties of Granular Cold‐Water‐Soluble Maize Starch by Ultrasonic‐Assisted Alcoholic‐Alkaline Treatment

Abstract

Starch solubility is of great significance in the food industry. Here the authors present a new method for preparation of granular cold water soluble maize starch by the ultrasonic‐assisted alcoholic‐alkaline treatment. Independent factors including ethanol concentration (70–90%), sodium hydroxide concentration (3–5 mol L−1), ultrasonic power (250–350 W), ultrasonic time (15–25 min) are optimized to determine the optimal conditions by response surface methodology (RSM) and Box–Behnken design (BBD). An ethanol concentration of 80.4%, sodium hydroxide concentration of 3.98 mol L−1, ultrasonic power of 303.73 W, and ultrasonic time of 25 min are found to be the optimum conditions to obtain a higher solubility of maize starches (reaching to 75.17%). The modified maize starches are characterized by scanning electron microscopy (SEM), X‐ray diffractometry (XRD), and Fourier‐transform infrared spectroscopy (FTIR). Data indicate that the ultrasonic‐assisted alcoholic‐alkaline treatment causes changes in morphological and rheological properties of maize starch, and in turn can improve the cold‐water solubility of maize starch effectively.