Kinetics of proteolysis of ß-casein during ripening of Fynbo cheese salted with NaCl or NaCl/KCl and ripened at different temperatures

Abstract

The proteolysis of beta-casein during ripening of low-fat Fynbo cheese was studied using 1st-order kinetics to improve the knowledge of the beta-casein hydrolysis in Fynbo cheeses salted with NaCl or NaCl/KCl and ripened at different temperatures. Effects of ripening temperature, partial replacement of NaCl by KCl during cheese salting, and total salt concentration were evaluated. Central and external zones from cheeses at 1, 5, 10, 20, 30, 60, and 90 ripening days were analyzed by polyacrylamide gel electrophoresis. No significant differences in the kinetic parameters were observed between cheeses salted with NaCl and those salted with a NaCl/KCl brine. Kinetic constants were significantly affected by region within cheese and ripening temperature. Kinetic constant values were in the range of 0.004/d to 0.018/d, and the activation energy of the reaction was approximately 19 kcal/gmol.