Purification and identification of antioxidant peptides from Chinese cherry (Prunus pseudocerasus Lindl.) seeds

Chinese cherry seed protein hydrolysate (CPH) was prepared with enzymatic hydrolysis using Alcalase and Neutrase, to obtain antioxidant peptides. The CPH was gradually fractionated by ultrafiltration through 10, 5 and 3 kDa molecular weight cut-off (MWCO) membranes, then the potential sub-fraction F-IV-E(a) was gained from the active fraction F-IV (MW < 3 kDa) using gel filtration chromatography. F-IV-E(a)-4 and F-IV-E(a)-5 with the significantly higher (P < 0.05) antioxidant activities were obtained by reversed phase high performance liquid chromatography (RP-HPLC). F-IV-E(a)-4 and F-IV-E(a)-5 were identified as Phe–Pro–Glu–Leu–Leu–Ile (731.92 Da) and Val–Phe–Ala–Ala–Leu (520.61 Da) by the protein sequencer and the quadrupole time-of-flight mass spectrometer (Q-TOF MS), respectively. The results suggested that F-IV-E(a)-4 and F-IV-E(a)-5 may serve as potential antioxidants and might be evaluated as food additives, functional food and pharmaceuticals.