Detection and enrichment of goat milk oligosaccharides and their effects on the metabolism of intestinal flora in the SHIME model

Background

Goat milk oligosaccharides (GMOS) constitute a significant bioactive component of goat dairy products. Compared with the proteins and fats in goat milk, the studies on GMOS are relatively lacking.

Aims

This study aimed to optimise isolation protocols for GMOS and explore their regulatory influence on intestinal homeostasis based on the Simulator of the Human Intestinal Microbial Ecosystem (SHIME).

Methods

Liquid chromatography-triple quadrupole mass spectrometry was employed in this study to determine the content of GMOS. A complete randomised design was conducted to optimise the key factors influencing the ultrafiltration and enzymatic processes. Subsequently, the conditions were refined for GMOS enrichment in nanofiltration based on response surface methodology.

Major findings

The optimum conditions for the nanofiltration separation of GMOS were identified as 40°C for temperature, 3.78 L/min for flow rate, 0.96 MPa for pressure and a pH of 6.88. Compared to the initial content in goat milk, the total content of the nine GMOS increased 8.87 times after nanofiltration enrichment. Notably, 3′-galactosyllactose (13.21 mg/L to 1.13 g/L) demonstrated the most significant enrichment effect. These enriched GMOS stimulated the proliferation of beneficial probiotic bacteria and enhanced the production of short-chain fatty acids, thereby contributing to the alleviation of Escherichia coli-induced gut microbiota dysbiosis in the SHIME.

Scientific implications

The findings could provide valuable insights into the separation of GMOS and promote the development of functional goat milk-derived products.