Characterization of Resistant Starch Samples Prepared from Two High-Amylose Maize Starches Through Debranching and Heat Treatments

Abstract

The aim of the present study was to investigate effects of debranching, autoclaving-storing cycles, and drying processes (oven-drying or freeze-drying) on RS contents, thermal, pasting, and functional properties of high-amylose maize starches (Hylon V and Hylon VII). The resistant starch (RS) contents increased (<= 57.8%) with increasing autoclaving-storing cycles. RS contents of oven-dried samples were higher than those of freeze-dried samples due to ongoing retrogradation of starch during oven drying at 50 degrees C. Debranching caused a significant decrease in peak transition temperature and enthalpy values as compared with native starches. Solubility and water binding values of RS preparations were higher than those of native starches. Addition of native and autoclaved samples had improving effect on emulsion properties of albumin. Cold viscosity values of oven-dried samples were lower as compared with freeze-dried samples; this might be due to higher number of H-bonds in oven-dried samples expected to be formed during drying. Debranching and autoclaving-storing cycles caused decreases in peak, breakdown, and final viscosity values. The results of present study showed that debranching and heat treatments increased the RS contents and improved the functional properties of high-amylose maize starches.