In vivo antibacterial activity of whey protein derived from fermented milk of Iraqi buffalo

The present study aims to prepare fermented buffalo's milk rich with low molecular weight peptides by using lactic acid starters as a mixture. Skim milk sample was inoculated with 5% of the starter. The growing number of starter and anti-bacterial activity were studied after 24 hours of incubation. Protein and peptide concentration were determined before and after fermentation, then biological active peptides were isolated or separated and purified by gel filtration column of Sephadex G25. Finally antibacterial activity of the isolated peptides was study in vivo. The results of chemical analysis of fresh and fermented milk showed that the concentrations of protein were 0.817mg/ml and 0.501mg/ml before and after fermentation, respectively either peptide concentration were 0.4mg/ml before fermentation and 0.805mg/ml after fermentation. The number of starter was determining during the fermentation process after 6, 12, 18 and 24 hours of incubation and found an increase in the number of lactic acid bacteria. The initiation number was 6.2 × 105 but after the 24 hours the number increased of up to 1.3×106. Number of lactic bacteria decreased after 24 hours with the increase in the concentration of lactic acid combined with low pH value. Colonies of lactobacilli were isolated from fermented buffalo milk and was characterized by the typical characteristics for the purpose of a rating based on morphological and cultural characters. Gel filtration gave seventy-eight fractions. And depending on the absorbency on wavelength 280 were obtained four peaks, each peak represents a fraction. Peptide concentration was determined in each fraction, these concentrations were (0 and 0243 and 0902 and 0632) mg / ml of fraction 1, 2, 3 and 4, respectively. Fraction three contained a high concentration of peptide. The antibacterial activity of the third fraction was estimated. The results showed that the bioactive peptides of fermented milk have good efficacy in the treatment of diarrhea in laboratory animals.