Enzymatic hydrolysis of yeast proteins to antioxidant peptides by papain immobilized on gigaporous microspheres

Yeast proteins were enzymatically hydrolyzed into antioxidant peptides by papain immobilized on gigaporous poly(glycidyl methacrylate) (PGMA) microspheres. Papain molecules uniformly distribute on the outer and inner surface of PGMA microspheres, and the loading amount of papain on microsphere reaches 66.5 mg/g. In addition, the specific activity and activity recovery of papain after immobilization are 137.5 U/mg and 60.6%, respectively, which are much higher than that on commercial mesoporous microspheres. Subsequently, yeast proteins are hydrolyzed to antioxidant peptides with controllable activity by immobilized papain, and the highest antioxidant activity of product is 81.2 mol TE/g. Furthermore, immobilized papain retains 35% of its initial activity after 20 cycles.