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 id entified. It was observed that, during ripening until the most commercially valuable product was obtained, (60-90 days) only 16 compounds varied signi ficantly with time: butanoic, isovaleric, hexanoic, octanoic and decanoic f atty acids (p<0.001), together with heptanoic acid (p < 0.005), 2-methyl pe ntanone, 2-methyl heptanone, 2-methyl nonanone, methyl ketones (p < 0.001), ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl t etradecanoate, ethyl hexadecanoate and ethyl esters (p < 0.001). These chan ges could be described by means of zero order kinetics. Through a PCA analy sis 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 t he cases by their ripening time (0/18 days, 35 days, 53/67/82 days). (C) 19 99 Elsevier Science Ltd. All rights reserved.