摘要：Pasture intake is a major factor affecting the content and the distribution of the conjugated
linoleic acid (CLA) isomers in bovine milk fat. The aim of this study was to determine the CLA
contents and its isomeric distribution in milk, cheese and butter from Azores, a Portuguese archipelago in the Atlantic Ocean. The CLA isomers were analysed using Ag+-HPLC with three silver ion columns in series. Butter was the richest product in CLA, with a total of 6.58–7.72 mg$\cdot $g-1, whereas cheese presented the highest specific CLA content (12.40–14.00 mg$\cdot $g-1 fat). The CLA isomeric distribution showed a clear predominance of the bioactive cis-9,trans-11 isomer (from 72.26% to 82.59%). The trans-11,cis-13 CLA isomer, a useful indicator of pasture-fed cow's milk, varied from 2.22% to 3.91%. In conclusion, the Azorean dairy products have a relatively high amount of CLA, especially the cis-9,trans-11 isomer, constituting therefore a good source of these compounds for the human diet.
