Proteolysis pattern and functional peptides in artisanal Tulum cheeses produced from Mut province in Turkey

Abstract

The main purpose of this study was to determine proteolysis model and peptide diverseness of goat skin Tulum cheese using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses, respectively. Furthermore, bioactive properties of identified peptide sequences were investigated using online databases. Tulum cheeses produced from raw milk (without starter culture) by traditional methods in Mut province (Turkey) were obtained from local producers following their production and analyzed during 180 days of ripening. The evaluation of electrophoretic profiles by SDS-PAGE analysis indicated that 51.96% of αs-casein and 56.08% of β-casein hydrolyzed at the end of the cheese ripening. According to mass spectrometry results, 179 peptides were sequenced; of these, 65 from αs1-casein, 7 from αs2-casein, and 107 from β-casein. However, κ-casein derived peptides were not determined in Tulum cheeses during ripening. Generally, αs1-casein derived peptides originated from the N-terminal part of αs1-casein while β-casein derived peptides arose from the C-terminal part of precursor protein. Ten different functional activities ACE inhibitors, antimicrobial, antioxidant, anticarcinogenic, GLP-1 enhancer, DPP-4 inhibitor, immunomodulator, brain function enhancer, antidiabetic, and cathepsin B inhibitor have been detected. Among these functional features, ACE inhibitory peptides were found to have higher counts.