Characteristics of some physically modified starches using mild heating and freeze-thawing

Abstract

Granular starches of different origins (normal corn, waxy corn, potato and tapioca) dispersed in water (40% dry solids, w/v) were subjected to mild heating (1 h) at their onset temperatures (T-0) for melting (H), cooling (12 h at 4 degrees C) after the heat treatment (HC), and freeze-thawing (12 h at -20 degrees C and 1 h at 25 degrees C) after the heating and cooling (HCFT). Both mild heating and freeze-thawing induced the deformation of granule structure by releasing starch chains from granules, which could form outer layers on the surface of starch granules by drying the treated starches. The mild heating thus provided a stabilization effect against shear thinning during pasting. The HCFT-treated starches, especially, displayed the most significant changes in pasting viscosity with the greatest value of final viscosity. The gels prepared with the treated starches showed an enhanced rigidity with increased hardness and springiness. (C) 2017 Elsevier Ltd. All rights reserved.