Microfluidization and characterization of phycocyanin-based emulsions stabilised using a fumed silica

Phycocyanin (PC), a protein pigment obtained from algae, is attracting attention due to the search for new plant-based alternatives to stabilise food products. Furthermore, PC presents surface activity and is able to reduce interfacial tension to create droplets in emulsions. However, PC is sensitive to degradation; one potential solution is to use it in combination with other materials. In this study, using PC in combination with Aerosil 200 to stabilise food-grade nanoemulsions was studied via rheology, laser diffraction and multiple light scattering. First, the microfluidization technique was used to reduce the droplet size of PC-based emulsions to a minimum of 243 nm after six passes. However, the resulting emulsion presented poor physical stability with an extensive creaming process. Incorporating Aerosil 200 reduced the creaming process at low concentrations and completely inhibited it above 5 g/100 g of Aerosil 200. This study shows that a combination of PC and Aerosil 200 was able to stabilise nanoemulsions, with potential applications for food products.