Mechanism of Heat-Induced Gelation and Gel Properties of Soybean 7S Globulin

Abstract

The gelation of 7S globulin when heated at 100°C and 0.5 ionic strength was investigated. The minimum protein concentration required for gel formation was 7.5%. The minimum heating times with protein concentrations of 7.5% and above 10% were 20min and 15 sec, respectively. The hardness of gel formed above 12% protein concentration became maximum after 15 sec heating and then remained constant on subsequent heating. The gels were transparent. The gelation mechanism was presumed to be as follows. Soluble aggregates with molecular weights of around 1 million, the shapes of which are not uniform, are formed at first which then associate with each other randomly to form a cluster. Finally a gel, the structure of which seems to comprise aggregates of clusters, is formed. No SH/S-S exchange reaction participates in this process. These results show that the gel properties and gelation mechanism for 7S globulin are different from those for 11S globulin. © 1986, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.