Study on japonica rice starch and its gelatinization properties and edible quality of cooked rice

To evaluate the relationship between starch and its gelatinization properties and edible quality of japonica rice, ten japonica rice were taken as materials. Amylose content, crystallinity and chain- length distribution of debranched amylopectin were measured. The pearson correlation between starch properties and gelatinization properties were analyzed.Linear regression equations of starch properties and eating quality of cooked rice were established.The results suggested that the negative correlation of AM content and the breakdown value was extremely significant ( r =-0.781, p < 0.01) .The negative correlation of chain B1 with peak viscosity and breakdown value was extremely significant ( r =-0.878、p < 0.01; r =- 0.924, p < 0.01) . The positive correlation of Chain A with peak viscosity and breakdown value was extremely significant ( r = 0.874、p < 0.01; r = 0.938, p < 0.01) .Chain B2 had significant correlation with trough viscosity and breakdown valne only, B3 + had no significant correlation with gelatinization properties. Linear regression equations of hardness, adhesiveness, springiness, cohesiveness, resilience and sensory score of cooked rice were established by stepwise regression analysis. The regression equations can predict the edible properties of japonica rice. Japonica rice with higher chain A content, lower amylose content, chain B1 content and crystallinity had better eating quality.