支链聚合度对菠萝蜜种子淀粉热力学特性的影响及老化动力学分析

为了探究支链聚合度对淀粉老化的影响,利用差示扫描量热仪结合Avrami方程,研究不同支链聚合度菠萝蜜种子淀粉(jackfruit seed starch,JFSS)凝胶后贮藏过程中的老化焓变和老化动力学。结果表明:支链聚合度降低,JFSS凝胶后老化过程形成更多趋于有序排列的结晶,老化速率从0.336增加到0.513,不同聚合度JFSS成核方式为瞬间成核;随贮藏时间的延长,JFSS老化度增大;支链聚合度与Avrami指数呈显著正相关(p<0.05);支链重均聚合度与凝胶化焓呈极显著负相关(p<0.01),数均聚合度凝胶化焓呈显著负相关(p<0.05);支链重均聚合度与贮藏0~7 d的老化焓变均呈现显著负相关(p<0.05)。支链聚合度是影响淀粉贮藏过程中老化特性的重要结构因素。

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.