Study on contribution of lipids towards the mechanical properties of milk fat globule membrane monolayer

Milk fat globule membrane (MFGM) stabilizes fat globule in milk in form of emulsion. The primary monolayer of MFGM is rich in proteins and secondary bilayer is rich in polar lipids. MFGM finds application as an additive in dairy and food industry (e.g. emulsions, infant formulas & reduced-fat products) for its emulsifying and stabilizing properties. MFGM received much attention in recent years due to both its health- beneficial & technological functionalities. This work has been carried out with the objective to understand contribution of various components towards the surface properties of complete MFGM. MFGM was isolated from fresh raw cream. During isolation of MFGM apart from polar lipids and MFGM proteins, neutral lipids are also isolated which have their origin in fat globules but are often considered as a constituent of MFGM. The MFGM was further fractioned into lipid fraction, defatted fraction and polar lipids. The mechanical properties of monolayer were studied for the above fractions using Langmuir film balance. Study of surface properties can also be linked to their techno-functional properties by calculating film elasticity of the compression isotherm which can be linked to emulsifying and stabilizing properties. The analysis of compression isotherms revealed that film elasticity is highly influenced by polar lipids. The behaviour of the MFGM appeared to be influenced by neutral lipid and defatted fraction during beginning of compression and by polar lipids at the end of compression