REASSESSMENT OF THE ANTIOXIDANT ACTIVITY OF CONJUGATED LINOLEIC ACIDS

The anticarcinogenic effect of conjugated linoleic acids (CLA) has bee n attributed to their antioxidant activity. Strong evidence is lacking , however, to substantiate that CLA is an antioxidant. The objective o f this study was, therefore, to test whether CLA is an antioxidant or a prooxidant in canola oil. The oxidation was conducted at 90 degrees C by monitoring oxygen uptake and changes in linoleic acid and alpha-l inolenic acid. Free CLA and CLA methyl ester (CLAME) accelerated lipid oxidation in canola oil. The prooxidant activity of CLA and CLAME was dose-dependent at concentrations ranging from 0.1 to 1.0% in canola o il heated at 90 degrees C. CLA-containing triacylglycerol, however, wa s neither an antioxidant nor a prooxidant. Under the present experimen tal conditions, CLA was not an antioxidant in fats and oil.