Effect of Superheated Steam Treatment on Rice Quality, Structure, and Physicochemical Properties of Starch

Abstract

This study aimed to investigate the effect of superheated steam treatment on the cooking and eating quality of rice, and further explore the effect of superheated steam treatment on the structure, gel properties, and rheological behavior of rice starch. After superheated steam treatment, the optimal cooking time of rice was effectively reduced by 26.9%, and the taste value of rice was significantly improved, from 78.45 to 84.20, when treated at 155 °C for 10 s. Superheated steam treatment significantly reduced the amylose and protein content, and increased the average particle size of rice starch. Compared with the control, the enthalpy change (ΔH) in the superheated steam treatment rice starch decreased notably from 6.53 to 5.28 after treatment, the relative crystallinity of the starch was significantly reduced from 21.20 to 10.89, and the short-term order of the starch was enhanced owing to the rearrangement of starch molecules after gelatinization. The starch structure was more compact and orderly after the superheated steam treatment, which significantly improved the hardness, viscoelasticity, and strength of the gel. These results indicate that superheated steam treatment improves the quality of rice by changing the structure of rice starch.