Effects of amylose and amylopectin chain-length distribution on the kinetics of long-term rice starch retrogradation

Understanding the characteristics of long-term starch retrogradation is critical for developing functional foods with desirable textural attributes. The long-term retrogradation kinetics of 10 different rice starches with a wide range of amylose content were thus investigated in this study, focusing on their relations with the starch chain-length distributions (CLDs). Correlation analysis between the retrogradation parameters from differential scanning calorimetry (DSC) with starch CLDs showed for the first time that the amylose content had a parabolic relationship with the melting conclusion temperature and enthalpy of long-term retrograded starches, indicating that the amylose component has a bi-directional effect on the long-term amylopectin retrogradation property. Furthermore, the amount of amylose short-medium chains and amylopectin medium chains were negatively and positively correlated with the melting onset temperature of long-term retrograded starches, respectively. The information learnt from this study could be applied in the rice industry to improve the textural attributes of cooked rice.

Automated summary

This study investigated the long-term retrogradation kinetics of 10 different rice starches and found that amylose content has a parabolic relationship with the melting conclusion temperature and enthalpy of long-term retrograded starches. Additionally, the amount of amylose short-medium chains and amylopectin medium chains were negatively and positively correlated with the melting onset temperature of long-term retrograded starches, respectively. The findings could be applied in the rice industry to improve the textural attributes of cooked rice.