Abstract:

In this work, rice was subjected to heating treatment for different time periods. Rice starch was extracted from heated rice and used to explore the effect of heating time on its granular morphology, thermomechanical properties, gel characteristics and rheology behavior measured using SEM, DSC, texture analyzer and rheometer. Resistant starch content was determined by enzymatic hydrolysis method. With prolonged heating time, the swelling power and solubility of rice starch initially increased, followed by a decrease, and the content of resistant starch decreased by 18.01%－8.10% during 0－10 min. Starch granular morphology was converted to adhesive granules from single independent granules due to swelling. Gelatinization enthalpy value also decreased from 5.862 to 0.532 J/g. Different changes in the hardness and elongation of starch from heated rice were also observed. In addition, the shear stability of rice starch paste changed downward.

Key words: rice starch, resistant starch content, granule morphology, thermomechanical property, rheology behavior