Effects of Heat Shock Treatment on Rice Quality during Storage (Part 2)

Heat shock treatments (HSTs) using microwave radiation were performed on harvested rice (cv. Koshihikari) up to 60, 70 and 80°C, and kept additionally for 0, 1 and 3 min, following drying and storage at 40°C for 6 months. For control rice, during storage there was a decrease in protein and starch digestibility, increase in setback viscosity (SV), final viscosity (FV) and pasting temperature (PT), while peak viscosity (PV) increased rapidly for the first 2 months then decreased. The HSTs at 70 and 80°C were effective in maintaining a high value of starch digestibility and low value of PV during storage, while the HSTs at 60°C retarded changes of PV and FV values. The results showed that HST would benefit quality maintenance of stored rice.