Fatty acid composition of human milk triglyceride species. Possible consequences for optimal structures of infant formula triglycerides.
Human milk triglycerides (TGs) were separated into 14 fractions by silver ion high-performance liquid chromatography (HPLC) with light-scattering detection (LSD). Subsequent fractionation by reversed-phase HPLC-LSD resulted in 75 subfractions. The major 48 were analysed by gas chromatography for their intact TG and fatty acid (FA) compositions. Using a constrained non-linear optimization computer program, the FA compositions and abundances of 170 different TG combinations were calculated. The major two, 16:0/18:1/18:1 (11.8 mol%) and 16:0/18:1/18:2 (10.0 mol%), were almost twice as abundant as expected from random FA distribution. The apolarities of 16:0 and 18:0 seem to be modulated by unsaturated FAs (18:1, 18:2) or medium-chain FAs (MCFAs; 8:0-12:0). MCFAs were present in 19 mol%. Of these, 7.2 mol% are likely to harbour stereospecific structures with an MCFA at sn-3, 16:0 or 14:0 at sn-2, and 18:1 or 18:2 at sn-1. These structures are excellent substrates for lingual and gastric lipases, producing products that assist in duodenal TG lipolysis.
Central Laboratory for Clinical Chemistry, University Hospital Groningen, Netherlands.
C H
CH
Winter
E B
EB
Hoving
F A
FA
Muskiet
D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D005227:Fatty Acids / Q000032:analysis*; D005260:Female; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000032:analysis*; D008027:Light; D008895:Milk, Human / Q000737:chemistry*; D012542:Scattering, Radiation; D012834:Silver / Q000737:chemistry; D014280:Triglycerides / Q000032:analysis*
D005227:Fatty Acids; D014280:Triglycerides; D012834:Silver