Microbiological, physico-chemical and proteolytic changes in a Spanish blue cheese during ripening (Valdeón cheese)

The aim of this work was to study the microbiological, physico-chemical and proteolytic changes in Valdeón blue-veined cheese during ripening. Eight replicas of cheese were produced and a total of 48 cheeses were analysed. Lactic acid bacteria, mainly lactococci, were the predominant flora during the early stages of ripening, gradually being replaced by moulds and yeasts (8 log units). Enterococci and Enterobacteriaceae counts were very low or zero. This variety was characterised by a total solids content of 61.80 g per 100 g ^-1 of cheese, a salt/moisture ratio of 8.92 g salt per 100 g ^-1 moisture, a pH of 6.4-7.6 and a water activity of 0.917. At the end of ripening, primary and secondary proteolysis were very high, which resulted in an almost total degradation of αs1- and β-casein (approximately 90%). The peptide profile of the aqueous soluble extracts at pH 4.6 showed great complexity during ripening.