Influence of milk type, coagulant, salting procedure and ripening time on the final characteristics of Picante cheese

Picante da Beira Baixa cheese is a hard, spicy, salty traditional cheese with a minimum ripening time of 120 d that is manufactured in Portugal at a farm level only. The purpose of this work was to study the influence of several manufacturing conditions (viz, mixture of ovine and caprine milks, source of coagulant, level of NaCl addition, and duration of ripening period) on the final characteristics of this cheese following a (replicated) factorial design. Milk type proved to be a statistically significant technological parameter in terms of numbers of viable microorganisms of various genera and the extent of proteolysis, probably as a consequence of higher initial contamination of caprine milk. The type of coagulant had a major effect on proteolysis: values of water-soluble nitrogen for cheeses coagulated with animal rennet were in general lower than those for cheeses coagulated with plant rennet, but much smaller differences were detected between values of non-protein nitrogen; and breakdown of α(s)- and β-caseins was more extensive in Picante cheeses manufactured with plant rennet. The level of NaCl was a statistically significant parameter for all microbiological, physicochemical and chemical characteristics measured, an observation that is probably due to its capacity to reduce water activity. Ripening time did not have a significant effect on the numbers of viable staphylococci.