Sialic acid content of goat milk during lactation

- Types and concentration of sialic acid in four periods of lactation were evaluated.
- The method used was efficient in detecting the types of sialic acid in times evaluated.
- Concentration of sialic acid residues decreased at the end of lactation.
- The stage of lactation influences the concentration and composition of the constituents compounds in goat milk.

Sialic acid, which is strategically linked to the surface of glycoproteins, glycolipids and free oligosaccharides, is involved in cellular interaction and communication processes. These processes are related to the main biological functions of sialic acid, which include immune system activation, brain development and protection against pathogens. The present study identified and quantified the classes of sialic acid (Neu5Ac and Neu5Gc) in goat milk during lactation. Forty-eight goat milk samples from twelve Saanen goats in four lactation stages were evaluated. Quantification, separation and identification of the compounds were performed using a chromatographic method. The goat milk contained high concentrations of sialic acids NeuGc and NeuAc, which then declined at the end of lactation. NeuGc had higher concentrations compared to NeuAc in all the lactation phases. Considering these aspects, the presence of these elements in goat milk provides a potential source of bioactive compounds that can be used as functional ingredient in foods.