Effect of Polymerization Degree of Amylopectin on the Thermal Properties of Jackfruit Seed Starch and Its Retrogradation Kinetic Analysis

In order to explore the effect of polymerization degree of amylopectin on starch retrogradation,differential scanning calorimetry and Avrami equation were used to study the retrogradation enthalpy and retrogradation kinetics of jackfruit seed starch(JFSS)gels with different polymerization degree of amylopectin during storage. The results showed that the polymerization degree of amylopectin decreased,the retrogradation process of JFSS gel formed more crystals with an arranged order,the retrogradation rate increased from 0.336 to 0.513,and the nucleation of JFSS with polymerization degree of amylopectin was instantaneous nucleation. The retrogradation degree of JFSS increased with storage time increasing. Polymerization degree of amylopectin had a significant positive correlation with the Avrami index(p<0.05). Weight-average polymerization degree of amylopectin had extremely significant negative correlation with the gelatinization enthalpy(p<0.01),and number-average polymerization degree of amylopectin had a significant negative correlation with the gelatinization enthalpy(p<0.05). There was a significant negative correlation between weight-average polymerization degree of amylopectin and retrogradation enthalpy for 0~7 days storage(p<0.05).The polymerization degree of amylopectin was an important structural factor that could affect the retrogradation properties of starch in the process of storage.