Modification of taro starch using ball milling process

Abstract

The modification of starch with green, sustainable, and chemical-free techniques is gaining interest in food applications. The present study examines the effect of ball milling on the morphological, functional, and rheological properties of taro starch over different milling durations (30-120 min). Fourier Transform Infrared (FT-IR) spectroscopy revealed structural changes, as evidenced by the broadening of OH stretching vibrations, new peaks at 2888 and 2924 cm^-1, and an increased peak intensity at 1018 cm^-1. These spectral changes indicate hydrogen bond disruption, molecular disintegration, and partial cleavage of glycosidic bonds. The decreasing trend in the ratio of 1041/1018 cm^-1 revealed that milling gradually increased the amorphous character of starch by destroying its crystalline structure. FESEM micrographs showed progressive granular structural fragmentation and roughness of the structure with longer milling duration. A significant reduction in particle size from 4185 nm (native starch) to 1896 nm (ball-milled starch for 120 min) was observed. Zeta potential and water absorption capacity declined while solubility improved. Ball milling application resulted in an increase in the peak time (11.93-13.32 min) and pasting temperature (75.15-77.10 °C) and a decrease in peak viscosities (26.82-19.91 Pa.s) and final viscosity (30.70-23.82 Pa.s). Texture evaluation of ball-milled starches indicated an initial increase in hardness and chewiness (30 min), followed by a decline at longer milling durations.

Keywords: FT-IR; Green modification; Rheology; Starch; Structural.