Production of conjugated fatty linoleic acid by lactic acid bacterias of human intestinal origen

Trabajo presentado en Joint Annual Meeting American Dairy Science Association (ADSA),celebrado en Quebec del 21 al 25 de julio de 2002.

Conjugated linoleic acids (CLA) are a mixture of positional and ge- ometrical linoleic acid isomers, the predominant ones are (c9t11) and 18:2 (t10c12) (t9t11). At each position the double bond can be ei- ther in the cis- or the trans- configuration. However, it is the cis-9, trans-11-octadecadienoic acid (18:2 c9t11) that is considered to be the most biologically active isomer. It is a naturally occurring fatty acid, present mainly in foodstuffs from animal sources. CLA is produced from polyunsaturated fatty acids by rumen microorganisms during biohydro- genation. The objective of this study was to determine the ability of dif- ferent cultures of lactobacilli isolated from human intestinal sources to produce CLA. Four different cultures, two strains each of Lactobacillus acidophillus and Lactobacillus casei were tested for their ability to pro- duce CLA from free linoleic acid. Different concentrations of linoleic acid (0, 0.05, 0.1, 0.2, 0.5 mg/ml) were added to MRS broth and sterilized skim milk inoculated with the cultures of the lactobacilli, and incubated at 37 ◦ C. Samples were taken at 0, 24, 48 and 72h. For each sample the amounts of individual isomers of CLAs (9c9t11, t10c12, t9t11) and total CLA (conjugated linoleic acid) were quantitated by gas liquid chro- matography. Growth in media containing 0.2% linoleic acid for 24h was most effective in CLA production. All the cultures were able to convert linoleic acid in conjugated linoleic acid in broth media and milk with a concentration range of (90.74-165.37 μ g/ml) and (79.54-143.73 μ g/ml) respectively. Conjugated linoleic acids have been reported to induce beneficial physiological effects incl uding anticarcenogenic, inhibition of arteriosclerosis and enhancement of immunological function in different species. The use of lactic acid bacteria able to deconjugate linoleic acid might enrich dairy products with CLA contributing to these beneficial effects. Probiotic bacteria, such as the ones in this study, also might produce CLA in the intestinal tract following their ingestion.

Peer Reviewed