We report on oil-in-water Pickering emulsions with high concentration of the oil phase that are stable against coalescence during storage. For this, viscous, edible oil (sunflower) was emulsified in the presence of naturally-derived cellulose nanocrystals (CNC) and a food-grade, bio-based cationic surfactant obtained from lauric acid and L-arginine (ethyl lauroyl arginate, LAE). The interactions between CNC and LAE were elucidated by isothermal titration calorimetry (ITC) and supplementary techniques. LAE adsorption on CNC surfaces and its effect on nanoparticle electrostatic stabilization, aggregation state, and emulsifying ability was studied and related to the properties of resultant oil-in-water emulsions. Pickering systems with tunable droplet diameter and stability against oil coalescence during long-term storage were controllably achieved depending on LAE loading levels. The underlying stabilization mechanism was found to depend on the type of complex formed, the LAE structures adsorbed on the cellulose nanoparticles (as unimer or as adsorbed admicelles), the presence of free LAE in the aqueous phase, and the equivalent alkane number of the oil phase (sunflower and dodecane oils were compared). Our results provide an example of an eco-friendly modification strategy for CNC by combining a food-grade cationic surfactant and a simple preparing protocol. The results extend the potential of CNC in the formulation of high-quality and edible Pickering emulsions. The functional properties imparted by LAE, a highly effective molecule against food pathogens and spoilage organisms, opens new opportunities in food, cosmetics, and pharmaceutical applications, where the presence of CNC plays a critical role in achieving synergistic effects with LAE.

Formulation and stabilization of concentrated edible oil-in-water emulsions based on electrostatic complexes of a food-grade cationic surfactant (ethyl lauroyl arginate) and cellulose nanocrystals

256th National Meeting (2018)

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