Effect of debranching and heat-moisture treatments on structural characteristics and digestibility of sweet potato starch

The effects of debranching treatment (DT) and debranching-heat-moisture treatment (D-HMT) on the structural characteristics and in vitro digestibility of sweet potato starch were investigated. The results indicated that DT and D-HMT decreased the percentage of starch fraction with degree of polymerization (DP) <= 13, increased the percentages of the other fractions, and decreased the molecular weight of starch sample. The D-HMT starch showed a considerable SDS content of 31.60%. Compared with the DT starch sample, the T-o, T-p, T-c, T-c - T-o. and Delta H of D-HMT starch samples for the second endothermal were increased significantly, crystalline pattern was altered from C-a to A type, the surface became more smooth. The pasting temperatures of DT and D-HMT starch samples were higher while the peak viscosities, breakdown and setback values were lower than that of native starch. These results suggested that structural changes of sweet potato starch by D-HMT significantly affected the digestibility. (C) 2015 Elsevier Ltd. All rights reserved.