Conjugated Linoleic Acid Production by Alkali Isomerization of Linoleic Acid from Idesia polycarpa Maxim. var. vestita Diels Oil

Conjugated linoleic acid refers to a group of positional and geometrical isomers of linoleic acid containing conjugated double bonds 1 .Conjugated linoleic acid has attracted growing interest due to its wide-range of biological effects such as immune modulation 2 , anticarcinogenic activity 3 , fat partitioning and metabolism 4 and lowering atherosclerosis 5 .However, endogenous production of conjugated linoleic acid isomers by humans from vaccenic acid is limited 6 .Increasing interest in its effects has resulted in development and wide availability of commercial conjugated linoleic acid nutritional supplements.Up to now, various methods have been developed to produce synthetic conjugated linoleic acid from linoleic acid, such as bacterial biosynthesis 7 , lipases 8 and photoisomerization 9 .However, biosynthesis from bacteria or lipase is expensive, requiring sensitive conditions and complex follow-up processes to recover the product 10 .Likewise, photoisomerization of linoleic acid is time-consuming and requires complicated equipment 11 .A more promising option for conjugated linoleic acid production is alkali isomerization, whereby linoleic acid is isomerized to conjugated linoleic acid under alkaline conditions 12 to produce mixtures consisting mostly of approximately equal amounts of c-9, t-11 conjugated linoleic acid and t-10, c-12 conjugated linoleic acid isomers 13 .