Food emulsifiers based on milk fat globule membranes and their interactions with calcium and casein phosphoproteins

Natural food surfactants were produced from membrane-derived fragments of milk fat globules (MFGM) obtained from cream and buttermilk by microfiltration with diafiltration followed by churning. The obtained MFGM fragments were demonstrated for their emulsifying and functional properties and as substitute of commercial phospholipids (lecithin). Fine emulsions (droplet size ∼1.2 μm) were obtained by stabilization of the oil/water interface after low energy sonication. Stable emulsions were obtained with lecithin in the pH range between 5.8 and 7.8, whereas MFGM components enabled better stability above pH 6. Coalescence took place in the presence of calcium, owing to electrostatic screening. The stability of the emulsions increased with the addition of casein, which formed droplet flocs. The calcium-binding ability of MFGM is proposed to inhibit protein (casein) flocculation, leading to a highly interacting network that prevents phase separation and stable MFGM-based food emulsions.