Goats’ milk as a natural source of lactose-derived oligosaccharides: Isolation by membrane technology

Human milk oligosaccharides are thought to be beneficial for the infant with regard to their prebiotic and anti-infective properties. However, so far no milk from farm animals has been considered to be a good natural source of lactose-derived oligosaccharides for human nutrition. In this study, the characterization and quantitation of neutral and sialylated lactose-derived oligosaccharides in mature caprine milk was performed and compared to ovine, bovine and human milk. The quantification was carried out using high-pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), and the characterization was performed by fast atom bombardment mass spectrometry (FAB-MS). A large amount and variety of acidic and neutral oligosaccharides were found in goats’ milk when compared with cow and sheep milk. In addition, 15 new oligosaccharide structures were identified in caprine milk. In order to isolate the goats’ milk oligosaccharide fraction, a two-stage tangential ultrafiltration–nanofiltration process was selected. Tubular ceramic membranes with molecular mass cut-offs of 50 and 1 kDa, respectively, were employed. A virtually lactose and salts-free product containing more than 80% of the original oligosaccharide content was obtained.