Super stable Melaleuca alternifolia essential oil Pickering emulsions stabilized with cellulose nanofibrils: Rheological aspects

Melaleuca alternifolia essential oil (MaEO) has attracted technological interest in the pharmaceutical, cosmetic and food sectors for its outstanding and broad antimicrobial spectra. However, its active components are highly susceptible to oxidation due to weathering. Therefore, stabilization of the MaEO components is essential. In this work, we evaluated the stability and rheology of MaEO-in-water Pickering emulsions using cellulose nanofibrils (CNF) as an eco-friendly and sustainable stabilizing agent. Small amplitude oscillatory shear (SAOS) tests brought exciting information about the relationship between internal microstructure strength and the relaxation processes, retardation processes, and viscous flow behavior of the emulsions. Measurements of oil droplet diameter distribution and steady-state rheological tests indicate that the emulsions have super stability under static environmental conditions within 28 storage days. Also, the emulsions present steady-state viscosity suitable for applications in dysphagic foods, presenting a pronounced shear-thinning behavior appropriate to developing cream and lotion skin-care eco-friendly products for the human body.