Physical Properties of Normal and Waxy Corn Starches Treated with High Hydrostatic Pressure

Abstract

Water mixtures of normal or waxy corn starch were treated with a high hydrostatic pressure (HHP) of 600 MPa at 40°C for 1 h, and the effect of starch content (10-70% (w/w)) on the physical properties of HHP-treated starch was evaluated by differential scanning calorimetry (DSC), X-ray diffraction, water holding capacity, cold water solubility and optical microscopy. With decreased starch content, HHP-treated starches showed loss in gelatinizaion enthalpy, less sharp X-ray diffraction patterns, and reduced water holding capacity and cold water solubility. More enhanced reductions in water holding capacity and cold water solubility were observed with normal corn starch than with waxy corn starch. The morphology of HHP-treated starch differed between normal and waxy corn starches. When completely pressure-gelatinized, the granular shape of HHP-treated normal corn starch was retained, while that of HHP-treated waxy corn starch was disintegrated.