Targeted Absolute Quantification of Oligosaccharides in Saanen Goat Milk

To investigate the specific oligosaccharide composition, content, and proportional distribution in Saanen goat milk and to perform a comparative analysis with Holstein bovine milk, targeted absolute quantification of 23 target oligosaccharides was performed in Saanen goat milk and Holstein bovine milk using ultra-performance liquid chromatography-hydrophilic interaction chromatography-triple quadrupole mass spectrometry (UPLC-HILIC-QqQ MS). The method exhibited a limit of quantification as low as 10.0 ng/mL, recoveries ranging from 83.98% to 111.44%, and satisfactory precision, meeting the requirements for accurate quantitative detection of milk oligosaccharides. Eight oligosaccharides were detected in both Saanen goat milk and Holstein bovine milk, including 2'-fucosyllactose (2'-FL), 3'-fucosyllactose (3'-FL), lacto-N-neotetraose (LNnT), 6'-galactosyllactose (6'-GL), 4'-galactosyllactose (4'-GL), lacto-N-hexaose (LNH), 3'-sialyllactose (3'-SL), and 6'-sialyllactose (6'-SL). The total content of these eight oligosaccharides in Saanen goat milk was (109.28±10.00) mg/L, which was significantly higher than that in Holstein bovine milk (44.87±2.87) mg/L, 2.44 times that of the latter value (P<0.05). The relative proportions of neutral and acidic oligosaccharides were (42.96±2.50)% and (57.04±1.57)% in Saanen goat milk, and (32.44±4.37)% and (67.56±5.68)% in Holstein bovine milk, respectively. Furthermore, the mass concentrations of 2'-FL, 4'-GL, 6'-GL, 6'-SL and 3'-SL in Saanen goat milk were 2.03, 6.20, 2.53, 2.05 and 2.07 times those in Holstein bovine milk, respectively (P<0.05). The findings demonstrated that compared with Holstein bovine milk, Saanen goat milk not only had a higher total oligosaccharide content, but also a higher proportion of neutral oligosaccharides, highlighting its significant potential as a high-quality dairy source for infant formula and other functional food products.