Afuega'l Pitu cheese quality: Carbon dioxide addition to refrigerated milk in acid-coagulated cheesemaking

The suitability of milk preserved by refrigeration and CO2 addition for the manufacture of Afuega'l Pitu, a Spanish acid-coagulated short-ripened cheese, was evaluated at pilot scale using an autochthonous cheese starter. Cheeses manufactured, after milk pasteurisation, from vacuum degasified refrigerated CO2-treated samples (pH 6.2) were compared with two different control cheeses made from pasteurised milk either fresh or refrigerated. The multiplication and acidification capacity of lactic acid bacteria as well as the production of volatile compounds during cheesemaking and ripening were not affected by the previous refrigeration and CO2-treatment of raw milk nor by the residual CO2 still present in pasteurised milk after degasification and pasteurisation. Residual CO2 retarded the proteolysis although no differences on proteolysis and sensory properties were detected at the optimum time of consumption (15 days) between cheeses made from CO2-treated milk and those made from untreated control milk. CO2-treatment effectively prevents the decrease in cheese yield caused by the microorganisms present in raw milk of poor microbial quality. These results support the interest of the CO2-addition in preservation of milk for cheesemaking, specially when it has a high initial microbial load; the method can be satisfactorily used in the manufacture of Afuega'l Pitu cheese and may be extended to the production of other acid-coagulated cheeses.

This work was financially supported by the Comisión Interministerial de Ciencia y Tecnología of Spain (project PTR95-0117-OP) and by a Contract with the S. E. de Carburos Metálicos S. A. P. Ruas-Madiedo was the recipient of a fellowship from the Council of Villaviciosa (Asturias, Spain).

Peer Reviewed