The influence of cheese type and fat extraction method on the content of conjugated linoleic acid

Milk and dairy products, including cheeses, are the richest sources of CLA in our diet. Determination of CLA content in these products requires extraction of fat from the sample. Solvent extraction is the most-often used method for fat extraction. As an alternative method, extraction using supercritical CO2 (SC CO2) could be applied. The aim of the present study was to compare the influence of solvent extraction of fat and extraction of fat with SC CO2 on the content of conjugated linoleic acid (CLA) in ten different types of cheese. CLA content was determined by GC method after fat esterification. The type of cheese was of significance for the CLA content. The content of CLA in cheeses ranged from 0.44% to 1.31% when solvent extraction was used, and from 0.55% to 1.30% when SC CO2 extraction was applied. The method of fat extraction had no influence on the content of CLA in 3 samples of cheese. A significantly higher content of CLA after CO2 extraction was gained only in 1 sample of cheese, whereas in 6 samples the amount of CLA after solvent extraction was significantly higher than after extraction using SC CO2. On the basis of the obtained results, no clear influence of the extraction method on CLA content in cheeses was found. Further investigations with the special attention on the type and properties of cheese, pressure, temperature, extraction time and volume of extracted material are needed.