Effect of post-cooking storage on texture and in vitro starch digestion of Japonica rice

The effects of post-cooking storage conditions on texture, microstructure and kinetics of glucose release during simulated in vitro digestion of japonica rice (Oryza sativa L.) were investigated. Cooked rice was stored at low, medium and extreme temperatures (4, 30 and 90 degrees C) for two different durations (1 and 24 h). The surface firmness of cooked rice grains stored at 30 and 90 degrees C was significantly decreased with an increase in the storage duration, while an opposite trend was observed for samples stored at 4 degrees C. Rice grains appeared shrunken and distorted during in vitro digestion, regardless of the post-cooking storage conditions. The cooked rice stored at 4 and 90 degrees C, for 24 h showed significantly lower starch hydrolysis (%) than those stored for 1 h at similar temperatures. Pearson's product-moment correlation coefficient indicated a significant negative correlation (p<0.05) between the overall grain firmness and equilibrium hydrolysis (%) of stored cooked rice.