Free amino acids and water-soluble nitrogen as a ripening indices in Montasio cheese

Traditionally, in semi-hard and hard cheeses the development of proteolysis is followed by the increase of water-soluble nitrogen (SN) as a percentage of total nitrogen (TN), but the characterisation of proteolysis for each particular cheese must consider all the processes that lead to the formation of peptides, free amino acids and products of their catabolism. In Montasio cheese, a considerable variability in the SN values and the amino acid profiles of cheeses at the same stage of ripening was recorded. This variability was probably due to the different traditional technologies adopted. Therefore, no chemometric model could be set up to evaluate the typical nature of Montasio cheese. On the other hand, a relationship between the total free amino acid content and the SN/TN ratio was demonstrated and it was found that certain amino acids could be used as an index for determining the level of proteolysis reached by the Montasio cheese