In vitro determination of the antihypertensive activities of fresh beef and pastirma hydrolysates

In recent years, the effect of the biofunctional properties of foods, especially meat, on lifestyle-related diseases has been a popular area of research. Specifically, one of the most studied properties of meat products is the hydrolysis of muscle proteins into biopeptides that inhibit angiotensin-I converting enzyme (ACE), which balances tension levels in the body. The aims of this study were to investigate the nature of chemical changes in proteins during the traditional process of pastirma production, and to compare the coexistence and activity of ACE inhibitory peptides isolated from fresh meat (FM), pastirma before cemen covering (PBC), and pastirma (PS) samples. The effect of the different manufacturing phases of pastirma on the protein structure of meat was observed using Sodium dodecyl sulfate-poly acrylamide gel electrophoresis (SDS-PAGE). Acrylamide gel images demonstrated that some protein fractions were changed during the pastirma production process. Additionally, to determine the ACE inhibitory activity of FM, PBC, and PS, samples were hydrolyzed with pepsin and trypsin to simulate the human digestive system. All 3 samples (FM, PBC and PS) showed a systematic inhibition of ACE at 5 different concentrations, while undiluted samples showed inhibition rates of 85.55%, 62.4%, and 77.24%, respectively. IC50 values of the samples (FM, PBC and PS) were calculated as 1.13, 4.06, and 0.92 mg/ml, respectively. Among all the samples, PS hydrolysates exhibited the highest antihypertensive activity. Regarding protein oxidation, the number of thiol groups of FM was 477 μmol/100g while non-digested PBC and PS were 394 and 116 μmol/100g. Additionally, bromophenol blue staining indicated protein hydrophobicity, showing a 2-fold increase in the pastirma processing due to denaturation of protein structure. In conclusion, it might be considered that pastirma, a traditional meat product, contains a considerable number of constituents that could be utilized as functional food and nutraceuticals. The results may signify the importance of dietary alternatives to chemicals to prevent hypertensive diseases.