Proteolysis in reduced sodium Kefalograviera cheese made by partial replacement of NaCl with KCl

Kefalograviera cheeses (five trials) of different sodium content were made from split lots of curd by varying the salting processes, i.e. brine — and dry — salting, with NaCl (control) or a mixture of NaCl/KCl (3:1 or 1:1, w/w basis). The extent and characteristics of proteolysis in the cheeses were monitored during aging by Kjeldahl determination of soluble nitrogen fractions (water-soluble nitrogen [WSN], trichloroacetic acid [TCA]-SN, phosphotungstic acid [PTA]-SN), the cadmium-ninhydrin method for the determination of total free amino acids (FAA), urea-polyacrylamide gel electrophoresis of cheese proteins, followed by densitometric analysis of the αs1- and β-casein fractions, reverse-phase high-performance liquid chromatography (HPLC) analysis of the water-soluble extracts of cheeses, and ion-exchange HPLC analysis of FAA. The results showed that proteolysis was similar in control and experimental cheeses at all sampling ages, indicating that the partial substitution of NaCl by KCl in the manufacture of Kefalograviera cheese did not significantly influence the extent and characteristics of proteolysis during cheese aging.