Studies On Amylopectin Chain-length Distribution And Multiple Branching Degree And Its Correlations With Physicochemical Properties Of Rice

In this study,the branched-chain amylopectin was labeled with fluorescence-containing APTS as a derivative,and then the chain length distribution of amylopectin in 21 conventional rice cultivars was determined by laser-induced fluorescence detector of capillary electrophoresis.The multiple branching degree and average chain length of amylopectin in 91 conventional rice cultivars were determined by enzymatic method for the first time.The physiochemical indexes of rice quality of 91 rice cultivars were also determined and the correlation between them was analyzed.The feasibility of enzymatic determination of amylopectin structure in rice was verified.It was found that the amylopectin chain length distribution measured by capillary electrophoresis was significantly correlated with the amylopectin multiple branching degree in rice.It was proved that the capillary electrophoresis and enzymatic method confirmed each other in the determination of amylopectin structure in rice.It was found that the proportion of chain amounts in amylopectin different chain length ranges mainly affected peak time,onset gelatinization temperature,peak gelatinization temperature and end gelatinization temperature of rice.It was also related to some RVA parameters of rice,which was proposed that the difference of amylopectin chain length distribution leads to the difference in starch structure,and furthmore influenced the physiochemical properties of rice.The average chain length and multiple branching degree of amylopectin were determined by enzymatic method.The correlation between amylopectin structure and physiochemical properties of rice starch was analyzed,the amylopectin which contained more long chain,the more difficult for rice to gelatinize and rice would more easily retrograded,finally the rice taste quality would be influenced.The correlation between rice quality and physicochemical properties and the correlation between physiochemical properties of rice was also investigated.It was considered that amylose content was an important index to measure the quality of rice.The viscosity of rice was determined by rapid viscosity analyzer and its cooking and eating quality was predicted.It could be used as an auxiliary index for high quality rice breeding.The basic parameters of amylopectin fine structure provided a solid theoretical basis for the improvement of rice quality in the future.At the same time,the results that the effect of amylopectin on rice quality and physiochemical properties,as well as the relationship between rice quality and its physiochemical properties in this study,which had important guiding significance for mining high quality rice resources,guiding rice quality improvement and breeding high quality rice varieties.