Functional Properties of Microbial Transglutaminase Modified Soybean Glycinin and β-Conglycinin

Soybean beta-conglycinin and glycinin were polymerized by a microbial transglutaminase (MTGase), and some functional properties of these polymers, including solubility, heat stability and emulsifying, foaming, and gelling properties, were investigated. SDS-PAGE showed that the acidic subunits of glycinin and alpha, alpha' subunits of beta-conglycinin were easily susceptible to MTGase than basic subunits and beta-subunits, respectively. Although MTGase treatment led to the decreases in solubility and emulsifying activity of beta-conglycinin and glycinin, the significant improvements in their gelling and heat stability were observed (p < 0.05). In addition, the MTGase polymerization also increased the foaming property and emulsifying stability of glycinin. These results show that MTGase treatment could improve some functional properties of beta-conglycinin and glycinin, which provides a new opportunity to obtain specific functional properties of soy proteins used in various food systems.