Here we present a workflow for in-depth analysis of milk lipids that combines gas chromatography (GC) for fatty acid (FA) profiling and a shotgun lipidomics routine termed MS/MSALL for structural characterization of molecular lipid species. To evaluate the performance of the workflow we performed a comparative lipid analysis of human milk, cow milk, and Lacprodan® PL-20, a phospholipid-enriched milk protein concentrate for infant formula. The GC analysis showed that human milk and Lacprodan have a similar FA profile with higher levels of unsaturated FAs as compared to cow milk. In-depth lipidomic analysis by MS/MSALL revealed that each type of milk sample comprised distinct composition of molecular lipid species. Lipid class composition showed that the human and cow milk contain a higher proportion of triacylglycerols (TAGs) as compared to Lacprodan. Notably, the MS/MSALL analysis demonstrated that the similar FA profile of human milk and Lacprodan determined by GC analysis is attributed to the composition of individual TAG species in human milk and glycerophospholipid species in Lacprodan. Moreover, the analysis of TAG molecules in Lacprodan and cow milk showed a high proportion of short-chain FAs that could not be monitored by GC analysis. The results presented here show that complementary GC and MS/MSALL analysis is a powerful approach for characterization of molecular lipid species in milk and milk products. Practical applications : Milk lipid analysis is routinely performed using gas chromatography. This method reports the total fatty acid composition of all milk lipids, but provides no structural or quantitative information about individual lipid molecules in milk or milk products. Here we present a workflow that integrates gas chromatography for fatty acid profiling and a shotgun lipidomics routine termed MS/MSALL for structural analysis and quantification of molecular lipid species. We demonstrate the efficacy of this complementary workflow by a comparative analysis of molecular lipid species in human milk, cow milk, and a milk-based supplement used for infant formula.

中文翻译：

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通过 GC 和 MS/MSALL 对人乳、牛奶和富含磷脂的牛奶配方中的脂质种类进行全面和定量分析

在这里，我们提出了一个深入分析牛奶脂质的工作流程，该工作流程结合了用于脂肪酸 (FA) 分析的气相色谱 (GC) 和用于分子脂质种类结构表征的称为 MS/MSALL 的鸟枪式脂质组学常规。为了评估工作流程的性能，我们对人乳、牛奶和 Lacprodan® PL-20（一种用于婴儿配方奶粉的富含磷脂的乳蛋白浓缩物）进行了比较脂质分析。GC 分析表明，与牛奶相比，人乳和 Lacprodan 具有相似的 FA 谱，具有更高水平的不饱和 FA。MS/MSALL 深入的脂质组学分析表明，每种类型的牛奶样品都包含不同的分子脂质成分。脂质类组成表明，与 Lacprodan 相比，人乳和牛奶含有更高比例的三酰基甘油 (TAG)。值得注意的是，MS/MSALL 分析表明，通过 GC 分析确定的人乳和 Lacprodan 的相似 FA 谱归因于人乳中单个 TAG 种类和 Lacprodan 中甘油磷脂种类的组成。此外，对 Lacprodan 和牛奶中的 TAG 分子的分析显示，高比例的短链 FAs 无法通过 GC 分析进行监测。此处提供的结果表明，互补的 GC 和 MS/MSALL 分析是表征牛奶和奶制品中分子脂质种类的有效方法。实际应用：牛奶脂质分析通常使用气相色谱法进行。该方法报告了所有乳脂的总脂肪酸组成，但没有提供有关乳或乳制品中单个脂质分子的结构或定量信息。在这里，我们提出了一个工作流程，该工作流程集成了用于脂肪酸分析的气相色谱法和称为 MS/MSALL 的鸟枪式脂质组学例程，用于分子脂质种类的结构分析和量化。我们通过对人乳、牛奶和用于婴儿配方奶粉的牛奶补充剂中的分子脂质种类进行比较分析，证明了这种互补工作流程的有效性。在这里，我们提出了一个工作流程，该工作流程集成了用于脂肪酸分析的气相色谱法和称为 MS/MSALL 的鸟枪式脂质组学例程，用于分子脂质种类的结构分析和量化。我们通过对人乳、牛奶和用于婴儿配方奶粉的牛奶补充剂中的分子脂质种类进行比较分析，证明了这种互补工作流程的有效性。在这里，我们提出了一个工作流程，该工作流程集成了用于脂肪酸分析的气相色谱法和称为 MS/MSALL 的鸟枪式脂质组学例程，用于分子脂质种类的结构分析和量化。我们通过对人乳、牛奶和用于婴儿配方奶粉的牛奶补充剂中的分子脂质种类进行比较分析，证明了这种互补工作流程的有效性。