Annotation and curation of the bovine milk oligosaccharides library by advanced Mass Spectrometry

Project:

Annotation and curation of the bovine milk oligosaccharides library by

advanced Mass Spectrometry

Daniela Barile

 

Oligosaccharides
are a class of bioactive macromolecules found in mammalian milk that
are receiving a lot of commercial attention. These complex
carbohydrates are known to be in part responsible for the beneficial
effects of breastfeeding and perform a number of bioactive functions
including prebiotic enrichment of a protective microbiota, limiting
the virulence of several pathogens, and increasing postnatal neural
development.

Recent
research has documented that bovine milk contains several structures
analogous to human milk oligosaccharides; however, these molecules
are only present in bovine milk in trace amounts. Until recently, the
analysis of oligosaccharides from bovine milk was hindered by the
lack of effective analytical tools. Mass spectrometry with its
extremely high resolving power and mass accuracy, has become the
ideal method to study oligosaccharides in bovine and other mammals
milk.

The
samples selected to carry out this project were: bovine colostrum,
bovine whey permeate, bovine whey permeate concentrate, and cheese
curds, all obtained from pooled milk/whey and therefore
representative of the industrial reality.

Identification
of free oligosaccharides by mass spectrometry requires that they are
separated from the other components present in the mixture. Samples
from different dairy products and by-products were isolated using a
solid-phase extraction with porous graphitized carbon as stationary
phase. For more detail please refer to Barile et al., International
Dairy Journal (2009)

This
library was constructed using an Agilent 6200 Series HPLC-Chip/TOF
Mass Spectrometer system equipped with microfluidic Chip, HPLC-Chip
interface, microwell-plate autosampler, capillary sample loading pump
and nanopump.

This
library contains accurate mass measurements of oligosaccharides
masses, their monomeric compositions, and reproducible
chromatographic details (retention times) in order to provide a
method to rapidly identify oligosaccharide molecules in dairy
products/streams by simply matching the masses and retention times
experimentally obtained with the ones present in the library. It also
contains detailed information about the isomeric composition of each
oligosaccharide in the various product.

 

Download a spreadsheet of the oligosaccharides in bovine colostrum

Download a spreadsheet of the oligosaccharides in bovine milk

Download a spreadsheet of the oligosaccharides in bovine whey permeate

Download a spreadsheet of the oligosaccharides in bovine whey permeate concentrate

Download a spreadsheet of the oligosaccharides in cheese curds

 

Each file includes:

  • A pie chart showing the relative abundances (%) of individual
    oligosaccharides
  • An Histogram showing the absolute abundances (intensity cps) of
    oligosaccharides (including individual isomers)
  • A base peak chromatogram (BPC) profile

 

List of abbreviations:

  • TOF,
    Time-of-flight
  • RT,
    Retention time
  • BPC,
    base peak chromatogram
  • m/z,
    mass-to-charge ratio
  • Expt
    mass, experimental mass
  • Cal
    mass, calculated mass
  • Delta,
    difference between Expt and Cal masses
  • Hex,
    hexose (glucose or galactose)
  • HexNAc,
    N-acetylhexosamine (N-acetylglucosamine or N-acetylgalactosamine)
  • NeuAc,
    N-acetyl neuraminic acid or sialic acid
  • NeuGc,
    N-glycolylneuraminic acid