Conjugated linoleic acid content and isomer distribution during ripening in three varieties of cheeses protected with designation of origin

Cheeses have been identified as important sources of conjugated linoleic acid (CLA), a mixture of positional and geometric isomers with potential anticarcinogenic activity and other beneficial properties. The objectives of this study were to examine the effects of ripening on the overall CLA content as well as on the isomers profile using GC and Ag+-HPLC. Three Spanish cheeses Protected with Designation of Origin (Mahon, Manchego and Cabrales) were manufactured in different cheesemaking plants and monitored at different times during the ripening period. Total CLA content varied from 3 to 9 mg/g of total fatty acids and rumenic acid (9-cis, 11-trans C18:2, RA) represented more than 75% of total CLA. After RA, 7-9 (cis/trans plus trans/cis), 11-trans, 13-trans and 11-trans, 13-cis C18:2 were the main CLA isomers. The results achieved confirm that the effect of ripening on the total CLA concentration and isomer distribution was negligible. (c) 2006 Elsevier Ltd. All rights reserved.