Wageningen University, Laboratory of Food Chemistry, P.O. Box 8129, 6700 EV Wageningen, The Netherlands.
Carbohydr Polym. 2013 Oct 15;98(1):914-21. doi: 10.1016/j.carbpol.2013.07.003. Epub 2013 Jul 10.
Five xanthans were hydrolyzed to their repeating units using cellulases. Hydrophilic interaction chromatography with online electrospray ionization ion trap mass spectrometry and evaporative light scattering detection was used to analyze the oligomers released. It was concluded that six different pentamer repeating units (RUs) exists within a xanthan sample. The most abundant RU shows acetylation on the inner mannose and pyruvylation on the outer mannose. The second most abundant RU shows acetylation on both the inner and the outer mannose. It becomes clear that more variations in the xanthan structure exist than generally recognized. Comparison of five different xanthan samples revealed that, although the molecular composition of xanthan samples can be exactly the same, the ratio in which the RUs occur can differ significantly. It is, therefore, concluded that xanthan samples should be characterized for both, their molecular composition and the relative abundance of the RUs present.
使用纤维素酶将五种黄原胶水解成其重复单元。采用亲水相互作用色谱法结合在线电喷雾离子阱质谱和蒸发光散射检测法分析释放的低聚物。结果表明，在黄原胶样品中存在六种不同的五聚体重复单元（RU）。最丰富的 RU 在内侧甘露糖上显示乙酰化，在外侧甘露糖上显示丙酮酸化。第二丰富的 RU 在内外侧甘露糖上均显示乙酰化。很明显，黄原胶结构中存在的变化比通常所认识的要多。对五种不同黄原胶样品的比较表明，尽管黄原胶样品的分子组成可以完全相同，但 RU 出现的比例差异很大。因此，结论是黄原胶样品应同时表征其分子组成和存在的 RU 的相对丰度。
