Conjugated Linoleic Acid (CLA) Formation in Edible Oils by Photoisomerization: A Review

Conjugated linoleic acid (CLA) that is commonly found in dairy and ruminant fats, is geometrical and positional isomer of linoleic acid (LA). Edible oils are not good sources of CLA. Attempts have been made to generate CLA in edible oils through photoisomerization procedures. CLA isomers have several proven health benefits. This article reviews procedures for producing CLA containing edible oils by photoisomerization approach and applications of photoisomerized oils for food uses. The article reviews (1) the photoisomerized production of CLA containing oils on lab scale, with customized equipment, at pilot plant scale; (2) the effects of iodine content, photoisomerization time, refining, interference from minor components of oils, efficacy of different edible oils containing LA, interference from antioxidants; (3) the chemical kinetics, oxidative stability; and (4) photoisomerized oils for frying oils and as drying oils.The review also briefly covers methods of measurement of CLA.