Characterization and structure-functionality analysis of starch in different layers of Lycoris chinensis bulb scales

Abstract

According to literature, the size distribution of starch granules varies significantly in different layers of Lycoris chinensis bulb scales, however its effect on structural and physicochemical properties of starch still remains unclear. In this study, outer, middle and inner layers of bulb scales of L. chinensis were compared for starch characteristics. Also, the structure-functionality association was investigated based on correlation analysis and hierarchical cluster analysis, using 37 starch quality traits. Compared to commonly consumed starches with similar amylose content, L. chinensis starch gel had lower hardness and viscosities. Among layers, starches varied significantly in particle size, physicochemical and structural properties. As compared to middle and inner scales, the starch in outer scales had higher amylose content, hardness and viscosities, but lower gelatinization temperature, weight-average molar mass and degree of polymorphism. Correlation analysis revealed significant correlations among traits, and interestingly, gelatinization temperature (Tp) was found positively correlated to traits of molecular weight (p < 0.05). The 37 traits of starch characteristics can be divided into three subgroups, as supported by the results of Pearson correlation analysis and hierarchical cluster analysis. In general, the information presented in the current study are useful for Lycoris bulb starch utilization and insightful for a better understanding of structure-functionality association of starch.