Structure and functional properties of acid thinned sorghum starch

Abstract

The structural and physicochemical properties of acid thinned sorghum starch prepared by treating starch with 2.2 M HCl at 30C for different durations (0-72 h) were studied. Amylose content and swelling power decreased and crystallinity increased with increase in acid hydrolysis. The scanning electron microscopy observations demonstrated that the acid thinning did not cause any disruption of the granular crystalline structure. However, the thermal properties observed by DSC showed a decrease in onset temperature (To) and enthalpy of gelatinization (δHgel) and an increase in conclusion temperature (Tc) upon acid hydrolysis. A significant reduction in starch pasting viscosities and gel hardness was also observed with acid thinning.