Stereospecific analysis of soybean triacylglycerols

Thirty soybean germplasm lines representing a wide distribution of fatty acid compositions were analyzed stereospecifically by using a chiral column to resolve the sn-1 and sn-3 positions of glycerol. The amounts of each acyl group on each of the sn positions were plotted vs. the amount of that acyl group in the triacylglycerols (TAG), and the plots were fitted by linear regression. The deviation of individual data points from the linear regressions was much greater than observed in previous studies. This could be attributed to the inclusion of a number of germplasm lines with elevated or reduced percentages of saturates. The stereospecific distributions could not be fit with previously suggested mathematical models because the plots had intercepts that were not allowed by the models. Statistical tests of the analytical procedure indicated that slight oxidation of or bias against the polyunsaturates had occurred and that the Grignard deacylation method gave slightly less representative analyses of the sn-2 position than pancreatic lipase deacylation on these TAG.