Changes in proteins of Domiati cheese during pickling

Abstract

SummaryDomiati cheese from homogenized and unhomogenized pasteurized milk was pickled for 4 months at room temperature. During pickling, the soluble tyrosine and tryptophan contents of the cheese gradually increased, indicating progressive proteolysis.Gel filtration of cheese extract on Sephadex G-25 revealed the presence of nitrogenous substances of various molecular weights. The maximum formation of amino acids and related substances was observed after 15 days storage.The changes in the electrophoretic patterns of proteins in the cheese during pickling indicated that both αs- and β-caseins were attacked. β-Casein, however, was much less affected.Homogenization was found to affect the formation of soluble nitrogenous substances, but was without effect on the electrophoretic pattern of the protein in the cheese.