Abstract:The purpose of this paper was to study the combined effect of high hydrostatic pressure (HHP) and enzymatic hydrolysis treatments on the allergenicity of ginkgo seed proteins (GSP). Four food-grade proteases (papain, alcalase, pepsin, and neutrase) were used to hydrolyze GSP after pre-treatment with HHP (200, 300, or 400 MPa). The extent of hydrolysis and molecular weights of the hydrolysates were measured by the o-phthaldialdehyde (OPA) method and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the allergenicity was assessed by western blotting and enzyme-linked immunosorbent assay (ELISA). The results showed that HHP could significantly improve the extent of proteolysis and reduce the antigenicity of GSP when the hydrolase was papain, alcalase, or pepsin, whereas neutrase showed a low degree of proteolysis and poor anti-allergenicity on GSP, and no significant improvement was observed upon high-pressure treatment. The highest degree of proteolysis and the optimal anti-allergenicity were obtained with papain or alcalase hydrolysis combined with HHPtreatment at 300 MPa or with pepsin hydrolysis combined with HHP treatment at 400 MPa. Under the above conditions, GSP could be hydrolyzed into polypeptides with molecular weights lower than 15 ku, the antigenicity was reduced over 95%, and all immunoreactive bands disappeared in the hydrolysates obtained. These results suggest that HHP can improve the degree of hydrolysis of GSP and reduce the residual antigenicity of hydrolysates, but the effects are dependent on the protease used and the magnitude of processing pressure.
