Abstract: Milk fat is secreted mainly in the form of fat globules (MFG) from the mammary glands of female mammals into the milk. The MFG particle size ranges from 0.2 to 15.0 μm. MFG sizes can affect the health of newborns and the physical and chemical properties of dairy products. As the size of MFG is determined by intracellular lipid droplets during the secretion of mammary epithelial cells, the regulation factors of lipid droplet size include intracellular triglyceride (TG) level and enzymes involved in the synthesis and hydrolysis of TG, enzyme, membrane phospholipid, and lipid droplet fusion, etc. This review mainly describes the synthesis and structure of MFG, the regulation of MFG particle size and its impact on human nutrition, dairy processing and lipid droplet size fusion, which will provide reference for the application of milk fat globule size.

Key words: milk, milk fat globule size, milk fat globule membrane, lipid droplets

摘要： 乳中脂肪主要以乳脂肪球（milk fat globule，MFG）形式从哺乳动物的乳腺中分泌到乳中，MFG粒径从?0.2 μm到15.0 μm不等，不同粒径MFG影响新生儿的健康及乳制品的理化特性。MFG粒径主要由乳腺上皮细胞中的?脂滴调控，脂滴大小的调控因素包括细胞内甘油三酯水平及其合成与水解过程中参与的酶、膜磷脂、脂滴融合等。本文主要综述MFG的合成和结构、MFG粒径对牛乳营养及乳制品加工的影响、脂滴融合对MFG粒径的调控，为?MFG粒径的应用提供参考。

关键词: 牛乳, 乳脂肪球粒径, 乳脂肪球膜, 脂滴