Abstract: The effects of different concentrations of baking soda solution on the cooking characteristics of brown rice including visual appearance, microstructure, color, texture characteristics of cooked rice, and the distribution of branched chain length of amylopectin in rice soup were investigated. The results showed that baking soda solution could make brown rice cortex shrunk or ruptured, increase the water absorption and the expansion rate of rice grains from 10.03% and 212.30% to 15.32% and 224.50%, respectively. Thus, the cooking time of brown rice significantly reduced. Compared with cooked brown rice without baking soda, the surface structure of cooked brown rice with baking soda was more seriously wrinkled and cracked, the degree of whitening increased and the yellow color was deeper. Moreover, the proportion of B2, B3 and A chains of amylopectin in rice soup decreased from 7.834, 2.458 and 24.922 to 6.81, 1.893 and 24.036, respectively. The hardness of brown rice decreased from 1 270.76 g to 983.72 g, and the viscosity increased from 85.79 g·s to 113.71 g·s. The overall sensory score increased, and the eating quality significantly improved. Therefore, adding an appropriate concentration of baking soda in brown rice during cooking can significantly improve the cooking and eating quality of brown rice.

Key words: baking soda; brown rice; cooking quality; eating quality