Enhancement of the oxidative stability of linseed oil in Pickering emulsions stabilized by polydopamine-modified cellulose nanocrystals

Virgin linseed oil-in-water emulsions stabilized by unmodified or polydopamine-modified cellulose nanocrystals (CNCs) were prepared in the presence of NaCl. The production of primary oxidation products ( i.e. conjugated dienes, or CD) was evaluated over time for both types of emulsions and compared with that of a control emulsion stabilized by a surfactant (sodium dodecyl sulfate or SDS). The evolution of CD over time was found to depend on the droplet interfacial area and concentration of introduced prooxidants (Fe(+II) ions). While unmodified CNCs retarded oil oxidation compared with SDS, their protective properties could be further improved by coating the nanoparticles with polydopamine, using a simple and environmentally-friendly protocol; a negligible oxidation of the oil was indeed measured after 55 days, despite the presence of a high concentration of Fe(+II) ions. • CNCs delay the primary oxidation products formation of emulsified linseed oil • Polydopamine coating of CNCs greatly enhance their oxidative protective properties • Oxidation rate depends on the interfacial area of linseed oil droplets.