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Content and distribution of conjugated linoleic acid isomers in bovine milk, cheese and butter from Azores

Teneur et distribution des isomères de l’acide linoléique conjugué (CLA) dans le lait de vache, le fromage et le beurre des Açores


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·g−1, whereas cheese presented the highest specific CLA content (12.40–14.00 mg·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.


(CLA) 3 Ag+- CLA CLA (6.58–7.72 mg·g−1), CLA (12.40–14.00 mg·g−1) cis-9, trans-11 (72.26% ∼ 82.59%) CLA trans-11, cis-13 CLA 2.22% ∼ 3.91% CLA, cis-9, trans-11


L’ingestion de pâture est le principal facteur qui affecte la concentration et la distribution des isomères de l’acide linoléique conjugué (CLA) de la matière grasse du lait bovin. L’objectif de cette étude était de déterminer la teneur en CLA et la distribution de ses isomères dans le lait, le fromage et le beurre des Açores, un archipel Portugais de l’Océan Atlantique. Les isomères de CLA ont été analysés par Ag+-HPLC, utilisant trois colonnes ioniques argentées, en série. Le beurre était le produit le plus riche en CLA, avec un total de 6,58–7,72 mg·g−1, tandis que le fromage présentait la plus grande teneur spécifique en CLA (12,40–14,00 mg·g−1 matière grasse). La distribution des isomères de CLA a montré une nette prédominance de l’isomère bioactif cis-9, trans-11 (de 72,26 à 82,59 %). La teneur en isomère trans-11, cis-13, indicateur de l’ingestion de pâture par les vaches, variait de 2,22 à 3,91 %. En conclusion, les produits laitiers des Açores ont une teneur relativement élevée en CLA, et particulièrement en isomère cis-9, trans-11, constituant ainsi une bonne source de ces composés pour l’alimentation humaine.

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Correspondence to José A. M. Prates.

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Pestana, J.M., Martins, S.I.V., Alfaia, C.M.M. et al. Content and distribution of conjugated linoleic acid isomers in bovine milk, cheese and butter from Azores. Dairy Sci. Technol. 89, 193–200 (2009).

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  • conjugated linoleic acid
  • milk
  • cheese
  • butter
  • pasture
  • acide linoléique conjugué
  • lait
  • fromage
  • beurre
  • pâture