Effect of cultivar and freezing on quality of cooked rice

This study investigated the effect of freezing on quality of cooked rice. Four rice cultivars: Khao Dawk Mali 105 (KDML 105), Pathum Thani 1 (PT 1), Khao Tah Haeng (KTH) and Leung 11 (L11) were used in this study. After cooking and freezing, the frozen cooked rice was freeze-thawed up to 3 cycles. For the textural properties and sensory evaluation, the results showed that the unfrozen and freeze-thawed cooked rice from KDML 105 had the lowest hardness and the highest stickiness whereas rice from L11 had the highest hardness and the lowest stickiness. In addition, the freeze-thaw cooked rice had a tendency to increase hardness and decrease stickiness with subsequent freeze-thaw cycles. From a scanning electron micrograph, the surface of the unfrozen cooked rice from KDML 105 and PT 1 exhibited a smooth surface more than the other cultivars; however, after repeated freezethaw cycles the surface of the cooked rice became rough, in particular KTH and L11 cultivars. These results indicated that the cultivar of rice grains influenced the quality of frozen cooked rice. The knowledge from this study can be useful for improving the quality of frozen cooked rice