Effect of microwave on the physico-chemical properties, cooking characteristics, and eating quality of japonica glutinous rice

To accelerate the post ripening of japonica glutinous rice, the effects of microwave accelerated aging treatment of japonica glutinous rice were studied. Using fresh harvested and naturally aged glutinous rice as a control, different microwave power (280 W, 420 W, 560 W, and 700 W) and treatment time (30 s, 60 s, 90 s, and 120 s) were used to accelerate the aging of japonica glutinous rice. The physicochemical indicators, cooking quality, texture and sensory quality of japonica glutinous rice were measured, and the storage characteristics indicators and cooking characteristics were also evaluated. Correlation analysis was conducted on the texture characteristics and sensory quality of glutinous rice, and principal component analysis and cluster analysis were used to comprehensively evaluate the glutinous rice. The results showed that the peroxidase activity and freshness value of japonica glutinous rice treated with microwave accelerated aging were lower than those of aged rice, but the fatty acid value of japonica glutinous rice treated with microwave decreased. The results of correlation analysis showed that the freshness aging degree of microwave accelerated aging glutinous rice was significantly negatively correlated with the water absorption and swelling rate of glutinous rice flour (P<0.01), significantly positively correlated with the pH value and solids of rice soup (P<0.05), and significantly negatively correlated with the hardness of glutinous rice (P<0.01). Compared with fresh harvested rice, aged glutinous rice had a higher hardness, greater chewiness, and lower overall sensory score. The comprehensive evaluation values of glutinous rice made from japonica rice treated with 560 W microwave power for 120 s and 700 W microwave power for 90 s were close to those of glutinous rice made from aged rice. In conclusion, microwave treatment under suitable conditions can improve the cooking quality of glutinous rice to produce changes similar to natural aging, but its fatty acid value content decreases.