Composition of goat's milk fat triglycerides analysed by silver ion adsorption-TLC and GC-MS

The triglyceride (TG) composition of goat's milk fat (from the milk of five herds collected monthly, from November to May) was studied using AgNO3-TLC anti GC-MS. Two of the four fractions obtained by TLC contained trisaturated TGs (SSS) and represented 55% of the total TGs; they were separated by the chain length of short-chain fatty acid (FA). The TGs of the remaining fractions were identified as mono- (SSM) and polyunsaturated, representing 29 and 16% of the total TGs, respectively. The distribution of two SSS fractions by carbon number (CN) was unimodal, with maxima at CN40 and CN36 respectively. The proportions of SSM and polyunsaturated TG were high between CN38-CN44 and CN46-CN54, respectively (mean values, 35 and 52%). One hundred and twenty-four peaks (some containing more that one molecular species of TGs) were detected in the chromatogram of total fat; the sum of the 30 peaks representing > 1 mol% was 70% of the total TGs. One hundred and thirty-seven molecular species were identified in the total goat's milk fat: 50% SSS, 30% SSM and 20% polyunsaturated. The most important in quantitative terms were medium-chain TGs containing C8, C10 or C12, and C18 : 1 as unsaturated FA. (C) 2000 Elsevier Science Ltd. All rights reserved.