不同乳源乳脂肪球的体外消化特性

In Vitro the Digestive Characteristics of Milk Fat Globules from Different Milk Sources

基于模拟婴幼儿胃肠道消化,采用粒径分布、Zeta电势和激光共聚焦扫描电镜观察不同乳源(牛、羊、驼)乳脂肪球(MFG)在消化各阶段物理特性的差异,采用气相色谱-质谱联用及滴定法,探究在不同消化阶段游离脂肪酸及脂解速率的变化,完善脂质消化的变化规律。结果表明,不同乳源MFG的颗粒粒径随消化时间的延长,均呈减小的趋势,与激光共聚焦显微镜染色后观察结果一致。在肠消化末端,驼乳MFG的平均粒径为(0.46±0.07)μm,显著低于牛乳MFG的粒径(P<0.05)。动态光散射电位仪测得电势绝对值显示,所有乳源MFG进胃肠消化后均表现出强负电性,其中肠消化末端的电位绝对值由大至小排序为羊乳>牛乳>驼乳。不同乳源MFG在肠道消化期间的脂解速率无明显差异,而驼乳MFG相较于其它两种乳源在不同消化阶段,棕榈油酸(C16∶0)的含量显著更高(P<0.05),长链脂肪酸比例更低。研究结果为驼乳产品的加工以及新型配方奶粉的制备提供新思路。

Based on the simulation of gastrointestinal digestion in infants and young children,particle size distribution,zeta potential and laser confocal scanning electron microscopy were used to observe the differences in the physical properties of milk fat globules(MFG)from different milk sources(bovine,ovine and camel)at different stages of digestion,Gas chromatography-mass spectrometry coupled to a titration method was used to study the changes in free fatty acids and lipolysis rate at different stages of digestion to refine the changing law of lipid digestion.The results showed that the particle size of MFG from different milk sources tended to decrease with increasing digestion time,which was consistent with the observation after laser confocal microscopy staining.At the end of intestinal digestion,the mean particle size of camel milk MFG was(0.46±0.07)μm,which was significantly lower than that of cow milk MFG(P<0.05).The absolute values of potentials measured by dynamic light scattering potentiometry showed that all milk source MFGs had strong negative electrical properties after entering the gastrointestinal digestion,with the absolute values of potentials at the end of the intestinal digestion in the order of goat's milk>cow's milk>camel's milk from largest to smallest.There was no significant difference in the rate of lipolysis of MFG from different milk sources during intestinal digestion,whereas camel milk MFG had a significantly higher(P<0.05)content of palmitoleic acid(C16∶0)and a lower proportion of long chain fatty acids compared to the other two milk sources at different stages of digestion.The results of this study provide new ideas for the processing of camel milk products and the preparation of new formulas.