Purification and Identification of Novel Antioxidant Peptides from Enzymatic Hydrolysate of Ginkgo biloba Seed Proteins

Ginkgo biloba seed proteins were hydrolyzed using alkali protease and pepsin to obtain antioxidant peptides. Ginkgo biloba antioxidant peptides (GKAPs) were separated by Sephadex G-25 and Sephadex G-10 gel filtration chromatography. The GKAP B3 exhibited highest antioxidant activity. B3 peptide was separated by reversed-phase high-performance liquid chromatography (RP-HPLC), and 2 peptides with good antioxidant activity, i.e., GKAPs C8 and C9, were obtained. The molecular weight and amino acid sequences of the peptides were identified by Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS). The results showed that the molecular mass of GKAP C8 was 452.21 Da and the amino acid sequence was YVGD (Tyr-Val-Gly-Asp), while the molecular mass of GKAP C9 was 988.49 Da and the amino acid sequence was LGNTDYAVH (Leu-Gly-Asn-Thr-Asp-Tyr-Ala-Val-His). GKAPs C8 and C9 exhibited good free radical-scavenging effect and inhibited the autoxidation of the linoleic acid system.