关键词: 米饭, 品质, 温度, 时间, 回生

Abstract:

Cooked rice was prepared from Wuchang rice harvested from Heilongjiang province. The quality properties of cooked rice: moisture content, enthalpy change (Δ Hr), textural attributes and sensory quality were monitored at intervals of 1 day during 14 days of storage at different temperatures (－18, 0, 4, 10 ℃ and 22 ℃). Results showed that storage temperature had little effect on the moisture content of cooked rice, which exhibited no significant change over the whole storage at the same temperature. However, both storage temperature and time significantly affected the enthalpy change, hardness and stickness of cooked rice. A continuous increase in enthalpy change and hardness was observed in cooked rice stored at 0, 4 or 10 ℃ and a maximum value was obtained for both indexes on the 14th day. The stickness continued to decrease with prolonged storage time and reached a minimum value on the 14th day. Cooked rice stored at －18 ℃ exhibited slowly increased enthalpy change and hardness and slowly decreased stickness, whereas no significant change was observed in sensory quality. Storage at 22 ℃ led to little changes in the above three indexes, but after 2 days, cooked rice completely spoiled. Therefore, the optimum storage temperature for cooked rice was 0－4 ℃, and lower temperature (－18 ℃) can inhibit starch retrogradation.

Key words: cooked rice, quality, temperature, time, retrogradation