INFLUENCE OF PASTEURIZATION OF MILK AND ADDITION OF STARTER CULTURES ON PROTEIN BREAKDOWN IN-OVINE CHEESES MANUFACTURED WITH EXTRACTS FROM FLOWERS OF CYNARA-CARDUNCULUS

Ovine cheeses were manufactured from raw milk (R), pasteurized milk wi thout starter addition (P), and pasteurized milk with starter addition (PS), using in all cases extracts of Cynara cardunculus as rennet and mimicking as far as possible the traditional manufacture process. The microbial counts were higher in R cheeses than in P cheeses, and the lowest microbial counts were found for PS cheeses. Such physicochemica l characteristics as moisture, fat, protein, NaCl content, and pH of t he three types of cheeses were similar to one another at each sampling time. In particular, pasteurization had no significant effect on prot ein breakdown as evaluated by either the water-soluble nitrogen, the t richloroacetic-acid (TCA)-soluble nitrogen, or the phosphotungstic aci d (PTA)-soluble nitrogen fractions. However, the TCA-soluble and the P TA-soluble fractions for the PS cheeses ripened for more than 28 days were higher than those for the R or P cheeses at similar ripening time s. The cheeses and their water-soluble extracts could not be distingui shed by urea-polyacrylamide gel electrophoresis for up to 7 days, but clear differences were apparent at 68 days of ripening for the PS chee ses with respect to the R and P cheeses. Copyright (C) 1996 Elsevier S cience Ltd