Pickering emulsions stabilized by various plant materials: Cocoa, rapeseed press cake and lupin hulls

Oil-in-water emulsions were fabricated using delipidated and finely ground plant powders from cocoa, rapeseed press cake and lupin hulls as stabilizing agents. Three different emulsification techniques were probed: microfluidization, sonication, and turbulent mixing by a rotating device. The emulsions were characterized by their droplet size distribution and by the coverage of the interfaces by solid particles. Fine and kinetically stable emulsions (> 1 month) could be obtained from the 3 plant powders. Sonication and microfluidization induced unwrapping of the large particles, giving them an expanded conformation that favored their anchoring on the oil droplets. The water-soluble fraction of the powders had minor effect on both emulsification and storage stability. At low powder content, the oil-water interfacial area displayed a linear variation with the amount of adsorbed particles, allowing a precise determination of the interfacial coverage.