Effect of added enzymes on the free amino acids and sensory characteristics in Ossau–Iraty cheese

A proteolytic and a lipolytic enzyme preparation were added (before clotting) to the milk used to manufacture Ossau–Iraty-type ewesʹ-milk cheese. The free amino acids were analysed by reversed phase-HPLC and the sulphosalicylic acid-soluble N fraction was quantified by the trinitrobenzenesulphonic acid method for use as indices of proteolysis during ripening. Sensory analysis of the cheeses began after two months of ripening. The lipolytic enzyme preparation did not increase free amino acid levels, with even a slight decrease being recorded at the beginning of ripening. On the other hand, the proteolytic enzyme preparation caused an appreciable increase in proteolysis, 20% higher than in the control batch after four months of ripening. The high level of exoproteolytic activity and concomitantly higher release of free amino acids related to sweet flavour, such as asparagine, serine, and proline, may have masked the bitter flavours previously reported in the literature when proteolytic enzymes have been added.