Abstract: Dual-enzymatic hydrolysis of Sloanea hemsleyana seeds with cellulase and papain was the best way for protein extraction as demonstrated by a comparison of the hydrolysis efficiencies of 6 different enzymes on Sloanea hemsleyana seeds. The effects of simultaneous or stepwise hydrolysis, cellulase/papain ratio, solid/solvent ratio, total enzyme dosage, temperature, hydrolysis time and pH on protein yield were investigated using one-factor-at-a-time design. Further, total enzyme dosage, temperature, hydrolysis time and pH were optimized using quadratic regression universal rotary combination design. The optimal hydrolysis conditions for protein extraction from Sloanea hemsleyana seeds were determined as follows: Sloanea hemsleyana seed meal was suspended in deionized water at a solid/liquid ratio of 1:25, and added simultaneously with cellulase and papain at a ratio of 6:4 until a total enzyme dose of 370 U/g for hydrolysis at pH 7.6, 57 ℃ for 80 min. Under these conditions, the extraction yield of protein from Sloanea hemsleyana seeds was 74.91%.

Key words: Sloanea hemsleyana seed protein, extraction, dual-enzymatic hydrolysis, quadratic regression universal rotary combination design