Background β-Galactooligosaccharides (GOS) are typically used in infant formula and adult nutritionals as a source of nondigestible oligosaccharides, which may bring beneficial effects through modulation of the gut microbiota. However, suitable methods for the determination of GOS in products with a high background of lactose do not exist. Objective The aim of this work was to develop a method suitable for the determination of GOS in infant formula and adult nutritionals and demonstrate suitability through single laboratory validation. Methods Reducing oligosaccharides are labeled with 2-aminobenzamide (2AB), separated by hydrophilic interaction LC, and determined assuming that all oligosaccharides give an equimolar response in the detector. The same sample is analyzed a second time after treatment with β-galactosidase to remove GOS. The difference in the determined oligosaccharides between the two measurements will be the GOS content of the sample. The method was validated in a single laboratory on infant formula and adult nutritionals. Results Recoveries were in the range 91.5–102%, relative standards of deviation (RSDr) were in the range 0.7–5.99%, and one sample had an RSDr of 8.30%. Except for the one sample with an RSDr of 8.30%, the performance is within the requirements outlined in the Standard Method Performance Requirements, which specifies recoveries in the range 90–110% and RSDr of below 6%. Conclusions The method is suitable for the determination of GOS in infant formula and adult nutritionals. Highlights A method has been developed which is suitable for the determination of GOS in products with a high background concentration of lactose (infant fromula and adult nutritionals). The method does not require access to the GOS ingredient used for the production of the finished product. It is also possible to separately quantify the amount of GOS containing three or more monomeric units in order to support dietary fibre analysis.

中文翻译：

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婴儿配方奶粉和成人营养品中 β-低聚半乳糖 (GOS) 的测定：单一实验室验证，首次行动 2021.01


背景 β-低聚半乳糖 (GOS) 通常作为不易消化的低聚糖来源用于婴儿配方奶粉和成人营养品中，可能通过调节肠道微生物群带来有益的效果。然而，尚不存在用于测定高乳糖背景产品中 GOS 的合适方法。目的 本工作的目的是开发一种适用于婴儿配方奶粉和成人营养品中 GOS 测定的方法，并通过单一实验室验证证明其适用性。方法 还原寡糖用 2-氨基苯甲酰胺 (2AB) 标记，通过亲水相互作用 LC 分离，并假设所有寡糖在检测器中给出等摩尔响应进行测定。用 β-半乳糖苷酶处理去除 GOS 后，对同一样品进行第二次分析。两次测量之间测定的寡糖的差异将是样品的 GOS 含量。该方法在单个实验室针对婴儿配方奶粉和成人营养品进行了验证。结果 回收率在 91.5-102% 范围内，相对标准偏差 (RSDr) 在 0.7-5.99% 范围内，一个样品的 RSDr 为 8.30%。除 RSDr 为 8.30% 的一个样品外，其他性能均符合标准方法性能要求中概述的要求，其中规定回收率在 90-110% 范围内，RSDr 低于 6%。结论该方法适用于婴儿配方奶粉和成人营养品中GOS的测定。亮点 已开发出一种适用于测定乳糖背景浓度高的产品（婴儿配方奶粉和成人营养品）中 GOS 的方法。 该方法不需要获取用于生产成品的 GOS 成分。还可以单独定量含有三个或更多单体单元的 GOS 的量，以支持膳食纤维分析。