Process Optimization for Enzymatic Preparation of Polypeptides from Egg Yolk Protein

In this study,enzymatic hydrolysis was used to prepare polypeptides from egg yolk protein.Two-step hydrolysis with alkaline protease and flavourzyme was found optimal for preparing polypeptides from egg yolk protein as demonstrated by a comparison of the effectiveness of flavourzyme,neutral protease,alcalase and protamex in hydrolyzing egg yolk protein.The response surface methodology was employed to investigate the effects of total enzyme dosage,alcalase-to-flavourzyme ratio,duration ratio between two hydrolysis steps and pH on degree of hydrolysis(DH) and polypeptide content.The optimal hydrolysis process was hydrolysis for 2 h with 0.8 g/100 mL alcalase at 55 °C,pH 7.2 and a substrate concentration of 10 g/100 mL and for another 2 h with 0.4 g/100 mL flavourzyme,resulting in a DH of(13.31± 0.5)% and a polypeptide content of(1.85 ± 0.5) mg/mL.