In Vitro Hemagglutination Activity of β-Conglycinin and Glycinin Fractions and Feeding Study of Non-Thermal Treated Soy Protein

The purpose of this study was to use non-thermal means to reduce hemagglutination activities of soy proteins and thereby improve the feeding quality of the resulting treated proteins. Two storage proteins in soybeans, beta-conglycinin- and glycinin-rich fractions, were shown to have in vitro hemagglutination activity. The activity of the beta-conglycinin fraction was not reduced by hydrolysis with single proteases, but the hemagglutination activity was fully eliminated by multiple enzyme treatments if it was first heated. However, the activity of glycinin fraction was not fully eliminated by either single or multiple enzyme hydrolysis. Pepsin and pancreatin hydrolysis, which was effective in eliminating hemagglutination activity of soybean agglutinin (SBA), was used to generate a feed material for in vivo evaluation of nutritional quality of soy white flake (SWF). SBA in reducing agent-treated then pepsin-pancreatin treated SWF was deactivated on analytical scale experiment, but not in the feed material. The treated SWF feed material did not improve chick growth performance compared with the raw SWF. However, chicks did not show enlargement of the pancreas or the intestines compared to the raw SWF feed, indicating deactivation of anti-nutritional factors. The trypsin inhibitors seemed to play a more important role than the hemagglutination activity of soy proteins in this nutritional test.