Effects of Heat Shock Treatment on Rice Quality during Storage (Part 1)

Harvested rice (cv. Koshihikari) was microwave-radiated up to 60, 70 and 80°C and kept heat-treated for 0, 1 and 3 min, dried and then stored at 40°C for 6 months. A pronounced change in chemical properties of control rice during storage was observed such as increase in fat acidity, soluble sugars, total amylose and insoluble amylose content, while a decrease was founded in total starch content, and soluble amylose content. The above changes also occurred in heat shock treated rice, but with certain extent of delay. The heat shock treatment (HST) delayed the increasing rate of fat acidity. The HSTs at 60 and 70°C were effective in keeping the values of total amylose and insoluble amylose content low. The results showed that HST would benefit rice quality maintenance during storage.