Emulsions stabilised with pectin-based microgels: Investigations into the break-up of droplets in the presence of microgels

Pectin-based microgels (MGP) are a promising alternative for the stabilisation of emulsions in vegan food-applications. Previous work has focused on the preparation of pectin-based MGP and on the effect of MGP concentration on the resulting emulsion properties. However, the effect of the emulsification process on microgel properties, such as size and integrity, still needs clarification. In this study, we emulsified oil in the presence of pectin MGP of different sizes. We found that throughout the emulsification process, microgel particles, ranging from 17 μm to 137 μm in size, were comminuted to a size that depended on the energy input of the emulsification parameters. Higher mechanical energy (Δp = 450 bar) resulted in microgels of mean diameters equal to 89 nm. This led to emulsions of a constant oil droplet size with a mean droplet size of 0.8 μm, regardless of the initial microgel size used for emulsion stabilisation. Lower energy inputs during the emulsification process resulted also in constant droplet sizes of around 2.8 μm for all initial microgel sizes. We also showed that the presence of oil enhances microgel breakage, leading to smaller microgels than in the absence of oil under the same constant process conditions.