Oligosaccharides are known to affect the health of infants. The analysis of these complex molecules in (human) milk samples requires state-of-the-art techniques. This study analyzed the composition and concentration of oligosaccharides in early (day 3) and mature (day 42) human milk as well as in five different infant formula brands. The oligosaccharide content decreased in human milk from 9.15 ± 0.25 g/L at day 3 to 6.38 ± 0.29 g/L at day 42 of lactation. All formulas resulted to be fortified with galacto-oligosaccharides, with one also fortified with polydextrose and another with long-chain fructo-oligosaccharides. About 130 unique oligosaccharide structures were identified in the human milk samples, whereas infant formula contained less diversity of structures. The comparisons indicated that composition and abundance of oligosaccharides unique to human milk are not yet reproduced in infant formulas. The analytical workflow developed is suitable for the determination of prebiotic oligosaccharides in foods that contain diverse carbohydrate structures.
Keywords: human milk; infant formula; mass spectrometry; oligosaccharides.