Evolution of lipolysis during the ripening of traditional Feta cheese

Lipolysis was studied during ripening of traditional Feta cheese produced in two small dairies, A and B. The cheeses were made from a thermized mixture of ewes'/goats' milk by using yoghurt as starter and artisanal rennet from lambs' and kids' abomasa (cheese A) or mixed artisanal rennet with calf rennet (cheese B). The acid degree value and the free fatty acids (FFA) contents in both cheeses increased sharply up to 18 d (pre-ripening period at 15 degrees C) and continued to increase throughout ripening. In both mature cheeses, acetic acid was found at high levels (13-18 % of the total FFAs). However, except for this, all FFA contents differed significantly (P < 0.05) between the two cheeses throughout ripening. The levels of individual and total C2:0-C8:0, C10:0-C14:0 and C16:0-08:2 fatty acids were significantly higher (P < 0.05) in cheese A than in cheese B. Presumably the difference, especially in the C2:0-0:0 content, was due mainly to the type of the rennet used. Butyric acid was the dominant FFA in cheese A (20 % of the total FFAs at 120 d), while the most abundant FFAs in cheese B were capric (18 %) and lauric acid (18 %). In general, the lipolysis degree of the two cheeses was higher than those reported for the industrially-made Feta cheese. In organoleptic evaluation, cheese A had a piquant taste that was attributed to its high content of butyric acid and showed a significantly (P < 0.05) higher total score than cheese B. (c) 2004 Elsevier Ltd. All rights reserved.