Relationship Between Texture Properties and Molecular Structure of A,B-Type Wheat Starch

The gel texture properties of wheat A-,B-type starch were investigated by using TA-XT2i texture analyzer.The results show that the B-type starch gel has higher springiness and cohesiveness than that of A-type starch gel,and the springiness and cohesiveness of the whole wheat starch is mainly influenced by B-type starch.In order to reveal the relationship between molecular structure and gel texture properties of A-,B-type wheat starch,the molecular weight distribution and the conformation and structure of A-and B-type wheat starch were investigated by method of gel permeation chromatography coupled with multiangle light scattering(GPC-MALS) and method of rotary rheology.The results show that the weight-average molecular mass(Mw) and number-average molecular mass(Mn) of A-type starch are both larger than that of B-type starch,and B-type starch has broader molecular weight distribution.Furthermore,the molecular conformations of A-and B-type were obtained by the slopes of the curves of log Rg-log Mw.It was found that the molecular conformation of B-type starch is random coil-like and has more branch structure,which tends to form network structure and causes the B-type starch to have a higher springiness and cohesiveness.