Effect of Pretreatment of Defatted Soybean Meal on Functional Properties of β-conglycinin

Soybean β-conglycinin was prepared from fresh defatted soybean meal, dry-heat treated defatted soybean meal and solvent extraction of defatted soybean meal. The effects of pretreatment on residual lipid content, lipoxygenase activity of defatted soybean meal and the functional properties of prepared soybean β-conglycinin were investigated. Dry-heat treatment did not result in significant changes in residual lipid content; however, lipoxygenase activity decreased by 7.69%. Solvent extraction treatment led to a significant decrease in the residual lipid content and lipoxygenase activity by 98.08% and 96.12%, respectively, indicating that solvent extraction could significantly inhibit lipid peroxidation of defatted soybean meal. Dry-heat treatment also caused a decrease in solubility, water-holding capacity, oil-holding capacity, emulsifying properties, foaming properties, and gelling properties of the prepared soybean β-conglycinin. These functional properties of soybean β-conglycinin showed an improvement when defatted soybean meal was treated with solvent extraction. These results provide a preliminary basis to improve the functional properties of soybean protein.