Physicochemical properties and molecular structure of starches from different wheat varieties and their influence on Chinese steamed bread.

Abstract

Starch is one of the key factors for the texture of Chinese steamed bread (CSB). In this study, the molecular structures and physicochemical properties of starches from 11 wheat varieties with amylose content (AC) of 1.75%-28.79% were investigated. Northern style CSB was made using these wheat varieties to explore the structure-property-quality relationship of starches. AC was negatively correlated with the pasting and gelatinization properties. The relative crystallinity (RC) had a negative correlation with AC but a positive correlation with gelatinization. The molecular structure results from the fluorophore-assisted capillary electrophoresis spectrophotometer indicated that the length of short amylopectin chains (βAp,i ) was positively correlated with hot paste and cool paste viscosities. The amount of medium amylopectin chains (hAp,iii ) was positively correlated with peak and breakdown viscosities but negatively correlated with setback viscosity. The hAp,iii had positive correlations with gelatinization temperatures and RC. The amount of long amylopectin chains (hAp,v ) had a positive correlation with peak temperature. For the CSB texture, βAp,i had negative correlations with hardness and chewiness, whereas had a positive correlation with resilience. The hAp,iii was negatively correlated with springiness and resilience. The hAp,v was negatively associated with resilience. PRACTICAL APPLICATION: Starch has a vital role in wheat flour products. Clarifying the structure-property-quality relationship of starches will help illuminate the role of starch molecular structure in CSB production and provide valuable information for the control of CSB quality. It also provides a significant reference for wheat breeding.