Laboratory of Food Chemistry, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, Netherlands.
Cluster Human Nutrition & Health, Department of Laboratory Medicine, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, Netherlands.
J Agric Food Chem. 2020 Jul 22;68(29):7800-7808. doi: 10.1021/acs.jafc.0c02684. Epub 2020 Jul 7.
Galacto-oligosaccharides (GOS) are used in infant formula to replace the health effects of human milk oligosaccharides, which appear to be dependent upon the structure of the individual oligosaccharides present. However, a comprehensive overview of the structure-specific effects is still limited as a result of the high structural complexity of GOS. In this study, porous graphitic carbon (PGC) was used as the stationary phase during ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS). This approach resulted in the recognition of more than 100 different GOS structures in one single run, including reducing and non-reducing GOS isomers. Using nuclear magnetic resonance-validated structures of GOS trisaccharides, we discovered MS fragmentation rules to distinguish reducing isomers with a mono- and disubstituted terminal glucose by UHPLC-PGC-MS. UHPLC-PGC-MS enabled effective recognition of structural features of individual GOS components in complex GOS preparations and during, e.g., biological conversion reactions. Hence, this study lays the groundwork for future research into structure-specific health effects of GOS.
半乳糖寡糖（GOS）被用于婴儿配方奶粉中，以替代人乳寡糖的健康效应，而这些健康效应似乎取决于存在的寡糖的结构。然而，由于 GOS 的结构高度复杂，因此对特定结构的影响的综合概述仍然有限。在这项研究中，多孔石墨碳（PGC）被用作超高效液相色谱-质谱（UHPLC-MS）中的固定相。这种方法在一次运行中即可识别出 100 多种不同的 GOS 结构，包括还原和非还原 GOS 异构体。使用经核磁共振验证的 GOS 三糖结构，我们发现了 MS 裂解规则，可通过 UHPLC-PGC-MS 区分具有单取代和双取代末端葡萄糖的还原异构体。UHPLC-PGC-MS 能够有效识别复杂 GOS 制剂以及例如在生物转化反应过程中单个 GOS 成分的结构特征。因此，本研究为未来研究 GOS 的特定结构健康效应奠定了基础。
