Extraction, identification and structure-activity relationship of antioxidant peptides from sesame (Sesamum indicum L.) protein hydrolysate

• Published in: Food research international Vol. 116; pp. 707 - 716
• Main Authors: Lu, Xin, Zhang, Lixia, Sun, Qiang, Song, Guohui, Huang, Jinian
• Format: Journal Article
• Language: English
• Published: Canada Elsevier Ltd 01.02.2019
• Subjects: Amino Acid Sequence; Antioxidant activity; Antioxidants - isolation & purification; Antioxidants - pharmacology; Benzothiazoles - chemistry; Biphenyl Compounds - chemistry; Enzymolysis; Models, Molecular; Oligopeptides - isolation & purification; Oligopeptides - pharmacology; Peptide match; Picrates - chemistry; Protein Hydrolysates - chemistry; Purification; Quantitative Structure-Activity Relationship; Seeds - chemistry; Sesame protein; Sesamum - chemistry; Subtilisins - chemistry; Sulfonic Acids - chemistry; Trypsin - chemistry; Quantitative structure-activity relationship; Purification; Peptide match; Sesame protein; Antioxidant activity; Enzymolysis
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2018.09.001

To elucidate the sequence, origin and structure-activity relationship of antioxidant peptides from sesame protein, sesame protein was hydrolysed by a dual-enzyme system comprised alcalase and trypsin, then this hydrolysate was fractionated by ultrafiltration and preparative HPLC. Subsequently, peptides in the high antioxidant activity fraction were identified by nano liquid chromatography-electrospray ionization-tandem mass spectrometry (Nano-LC-ESI-MS/MS), finally the structure-activity relationship of antioxidant peptide with the strongest activity in the sesame peptides was illustrated by comparative molecular field analysis (CoMFA). The results showed that seven novel antioxidant peptides were discovered, their sequences were as follows, RDRHQKIG, TDRHQKLR, MNDRVNQGE, RENIDKPSRA, SYPTECRMR, GGVPRSGEQEQQ and AGEQGFEYVTFR. The SYPTECRMR was the hydrolysate of 2S albumin, the others derived from 11S globulin. The SYPTECRMR whose IC50 Values of DPPH and ABTS were 0.105 mg/mL and 0.004 mg/mL respectively exhibited the highest antioxidant activity among the seven sesame peptides. The active site of SYPTECRMR tended to locate on Cys6 and Met8. A positive correlation between Cys6, Met8, the bulky C-terminal amino acid residue (Arg9), the negative charged group around sulphur-containing amino acids and the antioxidant activity of SYPTECRMR was observed from the CoMFA model. The results presented herein suggested that sesame protein hydrolysates have potential applications in functional food due to their high antioxidant activity, the CoMFA model could provide insight into the structure-activity relationship of antioxidant peptide, which is useful to screen, identify and design the novel antioxidant peptide. [Display omitted] •Seven antioxidant peptides are identified from sesame protein hydrolysis by Nano-LC-ESI-MS/MS.•Antioxidant peptide SYPTECRMR arises from 2S albumin, the others come from 11S globulin.•SYPTECRMR shows the strongest antioxidant activity among sesame peptides.•Sulphur-containing amino acids, steric and electrostatic factors dominate the antioxidant activity of SYPTECRMR.