Abstract: This study aimed to observe the changes in IgE binding ability of parvalbumin (major allergen) from sea bass Lateolabrax japonicus during fermentation by Staphylococcus xylosu (Sx). The alterations of proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The effects of fermentation by Sx on the allergenicity of allergens were investigated by Western blot and enzyme linked immunosorbent assay (ELISA) with rabbit anti-parvalbumin polyclonal antibody and sera from fish allergic patients. Subsequently, digestion of sarcoplasmic proteins by simulated gastric fluid (SGF) was carried out to evaluate the digestive stability. The results of SDS-PAGE showed that many proteins were degraded, although no obvious changes in parvalbumin (PV) were detected whose molecular mass was about 10 kD. The IgG binding ability of PV was decreased by 26.9% while the IgE binding ability was decreased by 22.3% after 60 h of fermentation. In SGF system, PV in fish fermented for 60 h was decomposed after being digested for 5 min, compared with 20 min of digestion for unfermented fish. In conclusion, the IgE binding ability of sea bass PV could be significantly reduced by fermentation with Sx, and PV was more readily degraded by pepsin after being fermented for 60 h.

Key words: Staphylococcus xylosus, fermentation, allergen, parvalbumin, simulated gastric fluid digestion