Physical Science

The objective of the present research is to develop a method for inhibition of damaged cooked rice (DCR) by using vacuum infusion technique, heated water soaking, and tempering treatment. Firstly, open cracked rice (OCR) grains were sorted by crack direction, then a composition rate of DCR grain, included in cooked rice was measured. As a result, transverse and longitudinal cracked grains were derived from the OCR grain. In addition, it was suggested that unevenness of water distribution within soaked rice kernel caused a difference in swelling distribution between central part and periphery of the kernel, according generated it flatly-broadened grain. Secondly, the composition rate of DCR grain in milled rice with low moisture content was measured for each treatment. As a result, the tempering treatment clearly inhibited to generate flatly-broadened grain, and vacuum infusion combined with processes of heated water soaking and tempering suppressed to generate transverse and longitudinal cracked grain. Finally, the hardness, stickiness and balance of cooked rice were measured. The value of balance for the treatment of vacuum infusion combined with heated water soaking and tempering which is positive by correlating with eating quality was the highest among all treatments, so it appeared that this treatment maintained the eating quality of low moisture content rice. Therefore, tempering treatment was considered as the best way for keeping the appearance and eating quality of low moisture content rice. Further experiment for investigating the optimization of tempering condition and finding the generation mechanism of flatly-broadened grain by using a morphologic approach is needed.