Functional improvements in β-conglycinin by preparing edible bioconjugates with ε-polylysine and dextran

β-Conglycinin was conjugated with ε-polylysine (PL) by means of microbial transglutaminase (MTGase) to improve its function. The β-conglycinin-PL conjugate was purified by dialysis. Composition of the β-conglycinin-PL was β-conglycinin:PL = 1:18 (molar ratio) which was confirmed by amino acid analysis. The β-conglycinin-PL was further conjugated with dextran (Dex) by the Maillard reaction. The β-conglycinin-PL-Dex conjugate was purified by dialysis. Conjugation was confirmed by SDS-PAGE and PAS staining. Composition of the β-conglycinin-PL-Dex was β-conglycinin-PL:Dex = 1:41 (molar ratio) which was confirmed by UV spectra measurement and phenol sulfuric acid method. Solubility of β-conglycinin in the acidic range was much improved by conjugation with PL and further improved by further conjugation with Dex. Emulsifying property of β-conglycinin in acidic pH range was much improved by conjugation with PL and Dex. Immunogenicity of β-conglycinin was decreased by conjugation with PL and Dex.