Thermal relaxation and mechanical relaxation of rice gel

Abstract

Rice gel was prepared by simulating the production processes of Chinese local rice noodles, and the properties of thermal relaxation and mechanical relaxation during gelatinization were studied by differential scanning calorimetry (DSC) measurement and dynamic rheometer. The results show that during gelatinization, the molecular chains of rice starch undergo the thermal relaxation and mechanical relaxation. During the first heating and high temperature holding processes, the starch crystallites in the rice slurry melt, and the polymer chains stretch and interact, then viscoelastic gel forms. The cooling and low temperatures holding processes result in reinforced networks and decrease the viscoelasticity of the gel. During the second heating, the remaining starch crystallites further melt, the network is reinforced, and the viscoelasticity increases. The viscoelasticity, the molecular conformation and texture of the gel are adjusted by changing the temperature, and finally construct the gel with the textural characteristics of Chinese local rice noodle.

Keywords

rice gel / rheological properties / thermal relaxation / mechanical relaxation