Growth and Proteolytic Activity of Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus in Reduced Sodium Kashkaval Cheese

Abstract

Reduced sodium Kashkaval cheese was produced from cow’s milk. Mixtures of NaCl, NaCl:KCl (1:1, 2:1) and NaCl:KH2PO4 (1:1, 2:1) were used for hot brining and salting of the cheddarized cheese curd. There were no significant differences (P < 0.05) in the count of Lb. delbrueckii ssp. bulgaricus after aging of Kashkaval samples. At the end of the ripening process the counts of Lb. delbrueckii ssp. bulgaricus reached 106 c.f.u./g and the counts of Streptococcus thermophilus varied from 104 to 105 c.f.u./g. Proteolysis during ripening of reduced sodium Kashkaval cheese, initiated by the starter microorganisms Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus, was studied through the changes in the levels of non-casein and non-protein nitrogen. It was observed that non-casein and non-protein nitrogen increased significantly (P < 0.05) during ripening. The amounts of non-casein and non-protein nitrogen accumulated in the studied Kashkaval samples were similar. That indicates that the partial replacement of NaCl with KCl or KH2PO4 does not cause significant changes in the course of proteolysis of Kashkaval cheese by Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus.