Multiple measurements of physical properties of cooked rice grains with different nitrogenous fertilizers

摘要

Japonica rice cultivars (Hinohikari, Reiho, Yumehikari) were given different N fertilizer treatments to investigate the effects of applied N on protein content and palatability, and to study relationships between fertilizer treatment, grain quality,and physical properties of grain. Three kinds of compression tests were carried out as multiple measurements. The overall hardness based on the high compression test (compression ratio: 90%) varied with rice cultivar rather than with fertilizer treatment. Surface hardness based on the low compression test (25%) was positively correlated with protein content. The surface hardness could distinguish differences in protein content among rice samples of the same cultivar. With increasing nitrogen fertilizerapplied, the surface hardness increased and the "overall evaluation" by the sensory test decreased. The ratio of stickiness and hardness in the middle compression test (45%) had a higher correlation with the "overall evaluation" than the protein content. It is concluded that physical properties of grain can discriminate the effect of N fertilizer on protein content and palatability.