Abstract: Soybean lecithin was added to protect the phospholipid layer on the surface of homogenized milk fat globule (MFG), and the homogenized MFG was used to encapsulate three fat-soluble nutrients including fish oil, vitamin E, and β-carotene. The addition of phospholipids could result in the formation of oil droplets with complete structure, smaller diameters, and larger absolute value of surface potential. During accelerated storage, the primary and secondary oxidation of fish oil was slowed down in homogenized milk with simultaneous and sequential addition of phospholipids and fish oil, and the content of lipid hydroperoxide, produced at the primary oil oxidation stage, was 1.28 and 1.79 mmol/mL at the end of storage, respectively, and was significantly lower than that (2.81 mmol/mL) without exogenous phospholipids. The content of malonic dialdehyde (MDA), produced at the secondary oxidation stage, was 4.29 and 6.64 nmol/mL, respectively, and was significantly lower than that (15.87 nmol/mL) without the addition of exogenous phospholipids. The preservation rates of vitamin E and β-carotene in phospholipid fortified milk were as high as 90.80% and 71.02%, respectively, after 12 days of storage, and were significantly higher than those (80.63% and 64.54%) of homogenized milk without the addition of exogenous phospholipids. Accordingly, the addition of exogenous phospholipids could reduce the degradation of vitamin E and β-carotene.

Key words: lecithin; milk fat globule membrane; fat-soluble nutrient; oxidation stability