Effect of Thawing Methods and Storage Periods on the Quality of Frozen Cooked Rice

This study attempted to determine the effect of various thawing methods and storage periods on the quality of frozen cooked rice. Frozen cooked rice was thawed at four different methods, such as pressure cooking, conventional cooking, microwave heating and thawing at room temperature after 10 days, 30 days and 90 days frozen storage. We conducted a physico-chemical analysis (moisture content, dehydration rates, degree of gelatinization, color value and texture) and sensory evaluation on the frozen-thawed cooked rice. The study showed that there were no significant differences on the quality characteristics of frozen-thawed cooked rice during the storage period of 90 days. However, the thawing method of pressure cooking caused high moisture content, rapid dehydration rates, and a high degree of gelatinization on the cooked rice. Thus, the desirability for the rice diminished because of the excess moisture content and the change of appearance and texture in the rice due to the high temperature. There were similiar quality characteristics to the cooked rice after frozen-thawing whether by conventional cooking or by microwave heating and just after cooking. Thawing at room temperature also caused a significant decrease in quality characteristics.