Influence of calf or lamb rennet on the physicochemical, proteolytic, and sensory characteristics of an ewe's-milk cheese

Roncal cheeses manufactured using lamb or calf rennet were compared for their chemical, proteolytic, and sensory characteristics. Trends in the overall physicochemical parameter values (pH, dry matter, fat, protein) were similar in both cheeses. Proteolysis of the nitrogen fractions was observed to take place faster in the cheeses made using lamb rennet (soluble nitrogen and non-protein nitrogen values around 20% higher than in the cheeses made using calf rennet up to 120 d of ripening). The values for the amino acid nitrogen did not exhibit any differences according to the type of rennet used. Urea-PAGE electrophoretic analysis of the caseins from the cheeses manufactured using both types of rennet showed that the β-caseins were less susceptible to proteolysis than the α-caseins. The cheeses made using lamb rennet had lower levels of residual β- and α s-casein at the end of ripening, again an indicative of more active casein hydrolysis when lamb rennet was used. The differences in proteolysis did not yield appreciable sensory differences.