Textural Characteristics and Bacterial Reduction in Glutinous Rice and Brown Rice Pretreated with Ultra-High Pressure

摘要

Ultra-high pressure (UHP) was applied to glutinous rice (Dongjin) and brown rice (Shindongjiri) to determine its effects on the textural characteristics of cooked rice and bacterial reduction in uncooked rice. Hardness and stickiness of the cooked glutinous and brown rice pretreated with 500 MPa for 5 min were significantly attenuated compared to that of the control rice (p<0.05). After the UHP treatment, particles of the glutinous and brown rice were observed to be finer when cross sections of the rice were analyzed using field emission scanning electron microscope. The total bacterial count in the brown rice treated with 600 MPa for 5 min was reduced from 107 CFU/g to 104 CFU/g, while the number of thermoduric bacteria in the brown rice was not significantly different after the UHP treatment. These results suggest that UHP may be an effective method for improving texture of dried rice and to reduce bacterial count in raw rice.