Formation of Pseudoglycinins from Intermediary Subunits of Glycinin and Their Gel Properties and Network Structure

Abstract

Intermediary subunits of soybean 11S globulin (glycinin) designated as IS I, IS II and IS III were isolated by DEAE-Sephadex column chromatography. Pseudoglycinins composed of one of the intermediary subunits alone were reconstituted. The pseudoglycinins were similar to the native glycinin as to molecular size, subunit structure and secondary structure. The turbidity and hardness of the heat-induced gels formed from pseudoglycinins were different from those derived from the native glycinin, depending on the constituent intermediary subunits. The results indicate that IS II is closely related to the generation of the gel turbidity and IS III plays an important role in increasing the gel hardness. The hardness of the gel seems to be determined by both the length and extent of branching of the constituent strands of the gel network structure.