Comparison of commercial supplements containing conjugated linoleic acids

Total conjugated linoleic acid (CLA) content and CLA isomeric distribution are two critical quality parameters of commercial CLA products. Four commercial CLA supplement samples were analyzed and compared for their total CLA content, CLA isomer distribution, fatty acid composition, color and hexane solubility. The CLA samples differed significantly in their total CLA contents, CLA isomer distributions, and fatty acid compositions. The total CLA contents were 65.1–77.9 mg/100 mg total fatty acids, while the cis-9,trans-11-CLA isomer accounted for 24.3–37.7 mg/100 mg total fatty acids. These differences may be explained by the fatty acid composition of the original oils used to prepare the CLA and the conditions of the isomerization reactions. Furthermore, these CLA supplements also differed in their color and solubility in hexane.