Study of proteolysis in miniature toma piemontese cheese made using wild bacteria

The effects of 35 strains of indigenous bacteria on proteolysis in model Toma Piemontese cheese were studied at 30 and 60 days of ripening. Proteolysis was assessed by urea-polyacrylamide gel electrophoresis (PAGE) of the pH 4.6-insoluble fractions of cheese, by reversed-phase high performance liquid chromatography (RP-HPLC) of the pH 4.6-soluble fractions at 30 and 60 days of ripening and by free amino acid (FAA) analysis at 60 days of ripening. Urea-PAGE showed that as1-casein was hydrolysed more than b-casein. The use of single strains markedly influenced the peptide profiles obtained by RP-HPLC of the cheeses. Significant differences in the levels of FAAs were also observed among the cheeses. The results of this study highlighted marked differences in the acidification and proteolytic activities of these bacterial strains.