Milk Oligosaccharides - Advanced Dairy Chemistry - page 315

At present, oligosaccharide structures are usually characterized by
resonance assignments of the reporter groups in one-dimensional 1 H-NMR,
of each chemical shift in one-dimensional 13 C-NMR and two-dimensional
NMR such as 1 H- 13 C correlated spectroscopy ( 1 H- 13 C COSY), heteronuc-
lear single quantum coherence experiments (HSQC), 1 H- 1 H homonuclear
Hartmann-Hahn experiments ( 1 H- 1 H HOHAHA), heteronuclear multiple
bond correlation experiments (HMBC), with the aid of MALDI-TOFMS or
fast atom bombardment mass experiments spectrometry (FAB-MS) analysis.
Further detailed information on structural and technological aspects of
human and bovine milk oligosaccharides can be obtained from a recent
review by Mehra and Kelly (2006).

8.3. Human Milk Oligosaccharides: Quantitative Aspects

Milk oligosaccharides can be quantified using reverse-phase or normal-phase
HPLC subsequent to pre- or post-column labeling techniques. Derivatizations
are often performed by condensation of 2-aminopyridine, 2-aminobenzamide,
2-aminobenzoic acid or 1-phenyl-3-methyl-5-pyrazolone to the reducing end of
the sugar aldehyde (Hase et al., 1978; Honda et al., 1989; Bigge et al., 1995; Fun
et al., 1995; Tokugawa et al., 1996; Fu and Zopf, 1999; Sumiyoshi et al., 2003a;
Sumiyoshi et al., 2003b). Sialyl oligosaccharides can be quantified by capillary
electrophoresis, with detection at 205 nm (Bao et al., 2007).
Mature human milk and colostrum contain 12-13 and 22-24 g/L of
oligosaccharides, respectively (Newburg and Neubauer, 1995). Oligosacchar-
ides constitute the third quantitatively largest component, after lactose and
lipids, of the dry matter of human milk.
The concentration of neutral oligosaccharides in human milk is greater
than that of acidic oligosaccharides. The neutral fraction contains many
fucosyl oligosaccharides. For example, Thurl et al. (1996) showed that
human milk contains significant amounts of 2 0 -fucosyllactose (2 0 -FL:
Fuc( 1-2)Gal( 1-4)Glc), lacto-N-fucopentaose I (LNFP I: Fuc( 1-2)Gal( 1-
3)GlcNAc( 1-3)Gal( 1-4)Glc), lacto-N-difucohexaose I (LNDFH I: Fuc( 1-
2)Gal( 1-3)[Fuc( 1-4)]GlcNAc( 1-3)Gal( 1-4)Glc) and lacto-N-tetraose

(LNT: Gal( 1-3)GlcNAc( 1-3)Gal( 1-4)Glc).
Representative acidic oligosaccharides of human milk are sialyl lacto-
N-neotetraose c (LST c: Neu5Ac( 2-6)Gal( 1-4)GlcNAc( 1-3)Gal( 1-4)Glc),
disialyl lacto-N-tetraose (DSLNT: Neu5Ac( 2-3)Gal( 1-3)[Neu5Ac( 2-6)]
Gal( 1-4)Glc), 3 0 -N-acetylneuraminyllactose (3 0 -SL: Neu5Ac( 2-3)Gal( 1-4)
Glc) and 6 0 -N-acetylneuraminyllactose (6 0 -SL: Neu5Ac( 2-6) Gal( 1-4)Glc)
(Thurl et al., 1996; Shen et al., 2000). Bao et al., (2007) stated that the most
prominent acidic oligosaccharide in the milk/colostrum is DSLNT, whereas
Asakuma et al. (2007) found that in colostrum it is LST c.