Abstract: In order to obtain an effective method for reducing the allergy of freshwater fish, the effect of enzymatic hydrolysis on antigen activity of mandarin fish protein was investigated. Neutral formaldehyde titration and indirect enzyme-linked immunosorbent assay were correspondingly used to detect the degree of hydrolysis (DH) and antigen activity of allergic protein from mandarin fish. Single factor analysis and response surface methodology were employed to analyze the effects of hydrolysis time, enzyme/substrate ratio, reaction temperature and pH as well as their interactions on DH and antigen activity. A mathematical regression model was established, and the optimal hydrolysis conditions were determined as hydrolysis pH of 8.00, enzyme/substrate ratio of 2940 U/g, reaction temperature of 40 ℃ and reaction time of 4 h. Under these conditions, the theoretical DH and reduction rate of antigen activity were 35.93% and 56.78%, respectively, very close to 36.67% and 58.33% of the actual results.

Key words: mandarin fish protein, papain, degree of hydrolysis, antigen activity, response surface methodology