Simplified Process for Soybean Glycinin and β-Conglycinin Fractionation

Publisher Website
Google Scholar
Abstract
A simplification of the pilot-plant scale modified Nagano method yielding two protein fractions, glycinin and β-conglycinin, by pH adjustment and ultrafiltration membrane separation was developed and compared with our pilot-plant-scale modified Nagano procedure and with a soy protein isolate pilot-plant procedure as our reference process. Two protein fractions, glycinin and β-conglycinin, were produced from our simplified process and compared to the three protein fractions, glycinin, β-conglycinin, and an intermediate protein mixture, produced with the modified Nagano method. The pilot-plant yields of glycinin, β-conglycinin, and intermediate mixture fractions from the modified Nagano method were 9.4, 10.3, and 4.8% [dry basis (db)], respectively. The yield of glycinin fraction of the simplified method was 9.7% (db), and it had a protein content and purity similar to those obtained with the modified Nagano method. The yield of the β-conglycinin fraction was 19.6% (db), which was twice that of the modified Nagano process. The protein content of β-conglycinin was 91.6% (db), and the purity was 62.6% of the protein content, which was 9% lower in purity than the modified Nagano method. Process optimization of the simplified method suggested the best operating conditions for the membrane filtration system were 20−25 psi inlet pressure and 200−250 L/min ultrafiltration recirculation speeds. Keywords: Pilot-plant protein fractionation; glycinin; β-conglycinin; soy protein separation; ultrafiltration