Capillary electrophoresis of sialylated oligosaccharides in milk from different species

• Sialylated oligosaccharides are important components of human milk.
• They are highly considered for their positive effect on human health.
• Oligosaccharide content of non-human milk has not been so well studied.
• Capillary electrophoresis was a valuable technique to study sialylated oligosaccharides.
• 3-Siallyllactose showed the highest relative concentration in all milk samples.

Oligosaccharides are relevant components of human milk, which have been quite well studied for their pre-biotic effect and their capacity in stimulating the immune system. Since oligosaccharides from milk of non-human mammals received so far less attention, the aim of this work was the application of capillary electrophoresis (CE) for the analysis of sialylated oligosaccharides in cow, goat and equine (mare and donkey) milk to possibly identify potential sources of oligosaccharides to use as health promoting ingredients in functional foods. Human milk was used as reference milk. A recent CE technique was applied to resolve and quantify 3-sialyllactose (3-SL), 6-sialyllactose (6-SL) and disialyl-lacto-N-tetraose (DSLNT). Analysis of non-human milk samples confirmed differences among species and individuals: DSLNT, which was the most abundant compound in human milk (455–805 μg/mL) was missing in most of the samples. In most cases, 3-SL showed to be the most concentrated of the quantified analytes, with values ranging from 12 to 77 μg/mL.