Isolation and Identification of Bioactive Peptides Formed in Sausage Fermentation: Antioxidant and Antimicrobial Properties

In this study, in order to investigate the effect of fermentation on bioactive peptide formation, samples were taken from sausages produced by traditional methods on the day of production (coded as day 0) and on the 1st, 3rd, 5th and 10th days of fermentation and peptide extractions were obtained. The extracted samples were subjected to enzymatic hydrolysis using two different enzymes (pepsin and trypsin) sequentially and the hydrolysates were injected into HPLC and separated into peptide fractions by means of a column filled with Sephadex G-25 stationary phase. Antimicrobial and antioxidant activities of peptide fractions were investigated under laboratory conditions. Antioxidant activity determinations were measured by DPPH radical scavenging capacity method and it was determined that there was no statistically significant difference between the antioxidant activities of the fractions obtained on the 0th and 10th days of fermentation and the highest antioxidant activity (16,18±0,04%) was reached on the 10th day. The antimicrobial activities of the same peptide fractions on Escherichia coli (ATCC 25922), Salmonella typhimurium (ATCC 14028), Listeria monocytogenes (ATCC 7644) and Lactobacillus pentosus (ATCC 8041) bacteria were measured under laboratory conditions and it was determined that the fractions did not have sufficient antimicrobial activity on Escherichia coli and Listeria monocytogenes bacteria, were moderately active on Salmonella typhimurium, and the 1st, 3rd, 5th and 10th day fractions were active on Lactobacillus pentosus. Peptide fractions obtained from fermented sausage samples subjected to enzymatic hydrolysis were subjected to LC/Q-TOF/MS analysis in order to determine peptide profiles after lyophilization. According to LC/Q-TOF/MS mass spectrometry data of peptide fractions obtained from sausage samples, a total of 10 different bioactive peptides were detected during 10 days of fermentation, including 6 different dipeptides (KD, LK, EL, KP, HL, IR) with antioxidant activity, 3 different tripeptides (GPP, GAA, RHA) and 1 tetrapeptide (CIRA) with antimicrobial activity.