Abstract: The aim of the current study was to use response surface methodology to optimize process conditions for the sequential hydrolysis of crab protein with papain followed by flavourzyme to achieve maximum hydrolysis degree. On the basis of one-factor-at-a-time experiments, a four-factor, three-level quadratic general rotary unitization design was employed to establish a quadratic polynomial mathematical model that describes hydrolysis degree as a function of four process conditions, and the established model was analyzed by drawing response surface and contour plots. The optimal hydrolysis conditions were hydrolysis with 5500 U/g papain at pH 5 and 55 ℃ for 1.5 h followed by 4.5 h with 2 LAPU flavourzyme. Under these conditions, the DH of crab protein was predicted to 31.19% and observed to 30.08% with a relative error of 3.69%. Further, a seafood seasoning was formulated with the obtained hydrolysate. Therefore, this enzymatic hydrolysis method can be used to prepare seafood seasonings with strong flavor, bright yellow color and convenient cooking.

Key words: crab, protein, hydrolysis, response surface methodology, eafood seasonings