Preparation And Antioxidant Mechanism Of Pleurotus Geesteranus Protein Hydrolysates

The accumulation of free radicals disturbs the balance between oxidation and antioxidation in the body,which triggers the oxidative stress response and ultimately lead to a series of chronic diseases.Therefore,characterization of the antioxidant substances that can pre-protect oxidative stress is of great significance.Pleurotus geesteranus protein(PGP)was chosen as the raw material in this study,and papain,alcalase,flavourzyme,pepsin and pancreatin were selected to hydrolyze the PGP.The in vitro chemical antioxidant experiments and oxidative stress cell model were used to study the antioxidant activity of P.geesteranus protein hydrolysates(PGPHs).Subsequently,the components with superior antioxidant activity were separated into different molecular weight by ultrafiltration,and the antioxidant activity and antioxidant mechanism of them were studied.The main research results are as follows:(1)Among the PGPHs digested by different enzymes,the alcalase hydrolysate(Alc-H)was rich in hydrophobic,negatively charged,and anionic amino acids,and showed the best antioxidant activity.In addition,Alc-H had a cytoprotective effect on the oxidative-damaged cells,which was related to that Alc-H could increase the activity of antioxidant enzymes and reduce the accumulation of reactive oxygen species in the cell.(2)Among the ultrafiltration fractions of Alc-H,the <3 k Da fractions had superior in vitro chemical and cellular antioxidant activity.In addition,the ultrafiltration component could alleviate oxidative stress by activating the Keap1-Nrf2 signaling pathway,increasing the activity of antioxidant enzymes and reducing the accumulation of reactive oxygen species in cell.In this study,the components of P.geesteranus with superior antioxidant activity was selected,and the antioxidant mechanism was initially clarified.This lay the foundation of the development and research of functional foods.