Purification and Characterization of Antioxidative Peptides Derived From Fermented Milk (Lassi) by Lactic Cultures

Fermentation of milk with lactic acid bacteria is the most suitable approach to enrich the bioactive peptides in fermented milk products. So in the present study, two sets of fermented milk (lassi) were prepared. The one lassi was prepared using standard Dahi culture NCDC-167(BD4) and the other one was made with the same Dahi culture combined with Lactobacillus acidophilus NCDC-15 as an adjunct culture. The preparation steps i.e. preheat treatment and incubation period were optimized by using response surface methodology to obtain maximum antioxidant activity. Lassi prepared with adjunct culture using optimized conditions showed an antioxidant activity of 0.66 +/- 0.01 mu M Trolox/mg protein which was significantly higher than that control (0.22 +/- 0.01 mu M Trolox/mg protein). Out of 59 peptide fragments of beta casein fermented by L. acidophilus and 24 peptides from control have been identified by LC-MS/MS. Most of the peptides showed the antioxidant activity. The therapeutic potential of fermented milk products could be improved by increased production of bioactive peptides through controlled fermentation using appropriate proteolytic starter strain.