Proteolysis and the optimal ripening time of Tounj cheese

Abstract Tounj cheese is a semi-hard, full-fat, smoked, farmhouse, fresh Croatian cheese that is produced from raw milk. It was presumed that using a ripening process would develop a new type of cheese. The objective of this study was to follow the basic proteolytic changes during the ripening of Tounj cheese and to determine the optimal ripening time in terms of the sensory quality of the cheese. Urea-polyacrylamide gel electrophoresis showed that α s1 -casein was degraded during ripening to α s1 -I-casein, α s1 -II-casein and some undefined products ( P 0.05 ). The degradation of s -casein was less extensive but significant ( P 0.05 ), and was due to the action of plasmin. The water-soluble nitrogen fraction and the 12%-trichloroacetic-acid-soluble nitrogen fraction increased during ripening ( P 0.05 ). In terms of sensory quality, the optimal ripening time of Tounj cheese was determined to be 4 weeks.