Stability and immunoreactivity of glycinin and β-conglycinin to hydrolysis in vitro

The present study was to compare the stability and immunoreactivity of glycinin and β-conglycinin to hydrolysis with pepsin, trypsin or cooperation of the two enzymes for different time intervals (0.5, 1, 15, 30, 60 and 120 min) at different ratios of enzyme/substrate (1:100, 1:10, 1:1 and 10:1) in vitro. The results showed that the immunoreactivity was positively related with stability of glycinin (r=0.776, P<0.05) and β-conglycinin (r=0.851, P<0.05). B polypeptide chain of glycinin was resistant to hydrolysis with trypsin, and β subunit of β-conlycinin was not liable to hydrolysis with pepsin. The two above proteins were little or not affected by incubation time and the enzyme/substrate ratio, while others' hydrolysed degree got higher with prolonging incubation time, and the hydrolysis accelerated with increasing enzyme/substrate ratio. Our results indicated digestive enzyme, incubation time and enzyme/substrate ratio had effects on stability and immunoreactivity of allergenic proteins. The most effective hydrolysis was cooperation of the two enzymes for glycinin and trypsin for β-conglycinin.