Increasing Slowly Digestible Starch Content of Normal and Waxy Maize Starches and Properties of Starch Products

Changes in the digestibility and the properties of the starch isolated from normal and waxy maize kernels after heat-moisture treatment (HMT) followed by different temperature cycling (TC) or isothermal holding (IH) conditions were investigated. Moist maize kernels were heated at 80°C for 2 hr. The HMT maize kernels were subjected to various conditions designed to accelerate retrogradation of the starch within endosperm cells. Two methods were used to accelerate crystallization: TC with a low temperature of –24°C for 1 hr and a high temperature of 20, 30, or 50°C for 2, 4, or 24 hr for 1, 2, or 4 cycles, and IH at 4, 20, 30, or 50°C for 24 hr. The starch granules were then isolated from the treated kernels. The starch isolated from HMT normal maize kernels treated by TC using –24°C for 1 hr and 30°C for 2 hr for 2 cycles gave the greatest SDS content (24%) and starch yield (54%). The starch isolated from HMT waxy maize kernels treated by TC using –24°C for 1 hr and 30°C for 24 hr for 1 cycle had ...