DISTRIBUTION OF DELTA-5-OLEFINIC ACIDS IN THE TRIACYLGLYCEROLS FROM PINUS-KORAIENSIS AND PINUS-PINASTER SEED OILS

Purified triacylglycerols (TAG) from Pinus koraiensis and P. pinaster seed oils, which are interesting and commercially available sources of Delta 5-olefinic acids (i.e., cis-5,cis-9,cis-12 18:3 and cis-5,cis-1 1,cis-14 20:3 acids) were fractionated by reversed-phase high performa nce liquid chromatog- raphy, and each fraction was examined by capilla ry gas-liquid chromatography for its fatty acid composition. A structu re could be assigned to more than 92% of TAG from both oils. In both i nstances, ca. 48% of the TAG were shown to contain at least one Delta 5-olefinic acid. In the great majority of TAG, our data showed that th ere is only one molecule of Delta 5-olefinic acid per molecule of TAG. This is compatible with theoretical calculations based on the proport ion of total Delta 5-olefinic in the oils. The cis-5,cis-9,cis-12 18:3 acid (14.2 and 8.6% of total fatty acids in the seed oils of P. korai ensis and P. pinaster, respectively) and the cis-5,cis-11,cis-14 20:3 acid (1.1 and 8.1% of total fatty acids in the seed oils of P. koraien sis and P. pinaster, respectively) are preferentially associated with two molecules of linoleic acid, and to a lesser extent, to one molecul e of linoleic acid and one molecule pi oleic acid, or two oleic acid m olecules. However, several other combinations occur, each in low amoun ts. The distribution of Delta 5-olefinic acids in TAG is evidently not random. Combining these results with the known preferential esterific ation of Delta 5-olefinic acids to the 1,3-positions of TAG would sugg est that most of these acids are present at only one of these position s at a time.