Comparison of physicochemical properties of Chinese and Japanese Japonica-Type rice varieties

The physicochemical properties of 10 Chinese varieties were compared with those of Japanese varieties. Chinese and Japanese varieties were not significantly different in amylose content. However, maximum viscosity and breakdown value were significantly lower in the Chinese varieties than in the Japanese varieties, and protein content and hardness/adhesion ratio were higher in the Chinese varieties. In the Japanese varieties, the lower the amylose content, the lower was the protein content, which is a preferable quality for palatability. However, the lower the amylose content, the higher was the protein content in the Chinese varieties. In the Japanese varieties, the protein content was negatively correlated with amylogram properties and positively with texture properties, but the opposite tendency was observed in the Chinese varieties. Among the physicochemical properties of the Chinese varieties, the most serious problem was protein content; especially there is a need to disrupt the negative correlation between protein content and amylose content.