Silver ion adsorption thin layer chromatography and capillary gas chromatography in the study of the composition of milk fat triglycerides

Fatty acid and triglyceride (TG) composition of milk fat and of the six fractions obtained by AgNO3-TLC were determined using capillary GC. The saturated (SSS) and monounsaturated (SSM) TGs accounted with two fractions each that were separated into butyrates and all the others; the remaining fractions were identified as di-and triunsaturated TGs, respectively. The total TGs and the SSM were distributed in similar proportions with respect to chain length. The molar percentages of SSS in short- and medium-chain TGs (60.2 and 45.0%, respectively) were higher than those of polyunsaturated TGs (11.5 and 21.6%, respectively). Most of the peaks found in the chromatogram of milk fat TGs were located predominantly in one of the AgNO3-TLC fractions. Thirty-seven peaks were >1%; from the most important in quantitative terms, six (three SSS and three SSM) contain butyric acid and four contain three long-chain fatty acids. Eighty-one molecular species of TGs were identified.