人乳与市售婴儿配方乳粉脂质比较研究

Comparative research on lipids between breast milk and commercial infant formulas

目的研究不同市售婴儿配方乳粉中脂质的结构、含量和组成特征,并将其与人乳对比分析。方法分别挑选了甲、乙(添加乳脂肪球膜)和丙3个品牌的婴儿配方乳粉,利用激光共聚焦显微镜对人乳和乳粉中的中性和极性脂质进行显微结构观察,并依靠气相色谱和拉曼光谱分析脂肪酸组成的差异。结果各乳粉复溶后脂质呈现球状结构,与人乳状态相似;各乳粉极性脂质碎片化存在,不同于人乳;观察到乙乳粉脂肪亮斑较少,其脂肪含量也较低,为16.3 g/100 g,其脂肪球粒径为2.74μm,显著大于其余乳粉。在脂肪酸组成上各种乳粉和人乳也有明显不同,乙乳粉的单不饱和脂肪酸含量较为接近人乳,含有较高二十二碳六烯酸(docosahexaenoic acid, DHA)、花生四烯酸(arochidonic acid, AA);拉曼光谱显示各乳粉脂质流动性较为接近。结论目前市售的婴儿配方乳粉的脂质存在状态与人乳存在差异,优化脂肪球的脂质微结构,使其状态更加趋近于人乳可能是未来婴儿配方乳粉的重要方向。

Objective To study the structure, content and composition characteristics of lipids in different market infant formula milk powder and compare with breast milk. Methods Three brands of infant formula milk powder were selected: A, B(adding milk fat globule membrane) and C. The microstructure of neutral and polar lipids in breast milk and milk powder was observed by laser confocal microscopy, and the differences of fatty acid composition were analyzed by gas chromatography and Raman spectroscopy. Results The lipid in each milk powder presented spherical structure, which was close to breast milk. The polar lipids of milk powder existed in fragmentation, which was different from that of breast milk. It was observed that milk powder B had less fat spots and a lower lipid content of 16.3 g/100 g, the diameter of fat globules was 2.74 μm, significantly larger than that of other milk powder. There were also obvious differences in the composition of fatty acids between various milk powder and breast milk. The content of monounsaturated fatty acids in milk powder B was similar to that in breast milk, and it contained higher ocosahexaenoic acid and arochidonic acid. The results of Raman spectrum showed that the lipid fluidity of milk powder was similar. Conclusion The lipid status of infant formula currently on the market is different from that of breast milk. Optimizing microstructure of lipid to make its status more similar to breast milk may be an important direction of infant formula milk powder in the future.