Changes in the volatile fraction during ripening of Mahon cheese

Mahon cheeses, manufactured in the Island of Minorca (Spain), were produced and ripened under controlled conditions. Cheeses were sampled and analyzed at different stages of ripening. Twenty-one major aroma components were identified. It was observed that, during ripening until the most commercially valuable product was obtained, (60-90 days) only 16 compounds varied significantly with time: butanoic, isovaleric, hexanoic, octanoic and decanoic fatty acids (p<0.001), together with heptanoic acid (p < 0.005), 2-methyl pentanone, 2-methyl heptanone, 2-methyl nonanone, methyl ketones (p < 0.001), ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl tetradecanoate, ethyl hexadecanoate and ethyl esters (p < 0.001). These changes could be described by means of zero order kinetics. Through a PCA analysis it was found that three factors explained ca. 87% of the total variance. According to the first two components the variables were grouped by their chemical characteristics (fatty acids, methyl ketones, ethyl esters) and the cases by their ripening time (0/18 days, 35 days, 53/67/82 days). (C) 1999 Elsevier Science Ltd. All rights reserved.