Isolation and determination of bioactive peptides in ripened Kars kashar cheese

In this study, peptide fractions obtained from ripened Kars Kashar cheese were evaluated for some bioactive properties such as antibacterial, antioxidant and ACE inhibitory activity. The antibacterial activities of 4 different peptide fractions (F1, F2, F3 and F4) released by direct and enzymatic hydrolysis of water-soluble extracts were investigated by disk diffusion and minimum inhibitor concentration (MİC) analyzes, and no inhibitory effects were observed on E. coli and S. aureus bacteria. In order to determine antioxidant capacities, DPPH and FRAP analyzes were applied and the highest antioxidant activity was observed as a result of FRAP, with 798.12 ± 14.18 mM Trolox/g extract in fraction of F4. As a result of DPPH analysis, the highest activity was determined as 70.13 ± 0.38 mM Trolox/g extract in F3 fraction. The percentage of fractions inhibiting ACE enzyme was found to be quite high in F1 and F2 fractions (with 100% inhibition). In addition, the smallest IC50 value was observed in the F2 fraction with 1.00 mg/mL. IC50 values of other fractions were determined from small to large F3 (IC50 = 3.22 mg/mL), F1 (IC50 = 7.96 mg/mL) and F4 (IC50 = 141.64 mg/mL). The lowest inhibitory effect was seen in F4 fraction with the highest IC50 value.