Antioxidant activity of yoghurt peptides: Part 2 – Characterisationof peptide fractions

Sabeena Farvin, Caroline Baron, Nina Skall Nielsen, Jeanette Otte, Charlotte Jacobsen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The aim of the present study was to elucidate previous findings showing that peptide fractions isolated from yoghurt had antioxidant effects. Therefore, peptides and free amino acids released during fermentation of milk were characterised. Yoghurt samples were stripped from sugars and lactic acid and subsequently fractionated by ultra filtration using membranes with cut off sizes of 30, 10 and 3 kDa. The peptides in these fractions were identified by LC–MS/MS. The identified peptides comprised a few Nterminal fragments of as1-, as2-, and j-casein, and several fragments from b-casein. Almost all the peptides identified contained at least one proline residue. Some of the identified peptides included the hydrophobic amino acid residues Val or Leu at the N-terminus and Pro, His or Tyr in the amino acid sequence, which is characteristic of antioxidant peptides. In addition, the yoghurt contained a considerable amount of free amino acids such as His, Tyr, Thr and Lys, which have been reported to have antioxidant properties. Thus, our findings confirm that the antioxidant effects of the peptide fractions from yoghurt are due to the presence of certain peptides and free amino acids with recognised antioxidant activity in these fractions.
Original languageEnglish
JournalFood Chemistry
Volume123
Issue number4
Pages (from-to)1090-1097
ISSN0308-8146
DOIs
Publication statusPublished - 2010

Keywords

  • Yoghurt peptides
  • Fish oil
  • Free amino acids
  • Oxidative stability

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