Effect of high-pressure homogenisation on the behaviour of oleosomes and milk fat globules at an air-water interface.

Growing demand for healthy and sustainable foods is accelerating the replacement of dairy ingredients with plant-based alternatives. Oleosomes, also known as oil bodies, are natural lipid droplets from oilseeds that form stable emulsions and may function as plant-based substitutes for MFGs. Because stabilisation at the air-water interface is critical for aerated products such as ice cream and whipped cream, this study compares the surface adsorption behaviour of thermally treated lipid suspensions containing MFGs or oleosomes. Both systems were analysed in their native state (D4,3 = 4.12 ± 1.32 μm for MFGs and 2.08 ± 0.97 μm for oleosomes) and after high-pressure homogenisation using a Microfluidizer at 69, 138, and 207 MPa, applied for one or two passes. In 15 g/dL lipid-based suspensions, increasing homogenisation pressure and pass number significantly reduced MFG size. In contrast, oleosomes at the same concentration showed no significant diameter changes beyond 69 MPa. Treatment at 207 MPa for two passes substantially modified the MFG membrane, with caseins dominating newly formed globule interfaces. These compositional changes led to slower interfacial equilibration and higher surface tension relative to native globules. Overall, these findings clarify key interfacial differences between dairy and plant lipid globules relevant to ingredient substitution.