Effect of increased pressure on the coated layer profile of steamed rice

In this study, rice was cooked using high pressure steam (HPS) via the absorption method to form the coated layer. The relationship between the adhesiveness of HPS-cooked rice and the composition of leached materials or the histological structure of its coated layer was studied. We found that as HPS levels increased, degradation of the cell wall structure and adhesiveness of cooked rice increased; moreover, substances leached out from rice more easily so that the weight of the coated layer increased from 0.4685 g/25 g to 0.9379 g/25 g. We also found that the main component of the coated layer was starch [74.71%-84.24% (w/w)], and its average chain length was 15.53-15.81, including 80.27%-82.83% (w/w) amylopectin. A change in relative molecular mass had a greater impact on the adhesiveness of cooked rice than did the chain-length distribution of leached starch.