Influences of Polyols on Thermal and Dynamic Viscoelastic Properties of Rice Starches during Gelatinization

The thermal and dynamic viscoelastic characteristics of indica (KSS7) and japonica (TNu67) rice starches (starch:water = 1:2) during gelatinization have been investigated in polyol solutions, with DSC and dynamic rheometry. The results indicate that the increments of some critical temperatures (To, Tp, TG′ and TG′max) in the thermograms and rheograms of rice starches are correlated well with the dynamic hydration number of polyol added. This firmly implies the importance of polyol‐water interaction in delaying the initial gelatinization. Polyol‐starch interactions appear to be different for low‐MW polyol and maltodextrin (DE = 8 ∼14) studied. As suggested by the changes in ΔH, tanδ and G′95values, the action from the plasticization of polyol presumably occurs during final gelatinization. These interactions and the plasticization of water and polyol cosolvents depend considerably on the granular structure of starch.