Label-Free quantitation of milk oligosaccharides from different mammal species and heat treatment influence

Milk oligosaccharides (MOs) exhibit significant variations in concentrations and patterns among different species. However, there is limited knowledge about milk oligosaccharides in domestic animals and the impact of heat treatment on them. Here, we developed an LC-ESI-MS/MS method to analyze 11 milk oligosaccharides in 7 distinct species simultaneously. The results showed that human milk presented a completely different composition pattern of milk oligosaccharides from animals. In detail, animal milk predominantly contained sialylated oligosaccharides, and human milk had high levels of fucosylated neutral oligosaccharides. Notably, sheep milk exhibited similarities to human milk in terms of oligosaccharides composition. Then, the milk samples from dairy cows were treated with two common industrial heat treatments. We found that 65 °C treatment had no significant effect on the concentration of milk oligosaccharides, whereas 135 °C heating was associated with their decline, suggesting that high temperatures should be avoided in the processing of oligosaccharides supplemented/enriched products.