Wet Ball Milling of Indica Rice Starch Effectively Modifies Its Multilevel Structures and Pasting Behavior

While the changes in starch physicochemical properties resulting from typical dry ball milling (usually requiring hours) have been widely studied, there has been limited knowledge regarding how wet ball milling (with liquid media) affects starch structure and properties. This work was to investigate the effect of wet ball milling on the multiscale structures and pasting behavior of indica rice starch. For this starch, increasing ball-milling time resulted in decreases in particle size, crystallinity, and double-helix content and increases in single-helix and amorphous contents. Only 15 min of ball milling effectively destroyed the semicrystalline lamellar structure and resulted in the cleavage of long chains from amylose and amylopectin backbones and marked decreases in pasting temperature and viscosity, while ball milling for an even longer duration did not cause significant changes in these aspects. Thus, this work shows the high efficacy of wet ball milling for modifying rice starch structure and properties.