Linalool Essential Oil/Nanocellulose-Based Pickering Emulsions: An In-Depth Investigation of Processing Parameters

Abstract This study aims to prepare nanocellulose-based emulsions using linalool essential oil using different processing parameters and correlating them with emulsions' stability and particle size. The investigated parameters were cellulose morphology (CNC or CNF) and concentration (0.5 or 1 wt%), essential oil concentration (20 or 30% v/v), homogenization speed (10,000 or 12,000 rpm), and time (3 or 7 minutes). The emulsions were tested by droplet size, morphology, and storage stability. The Design of Experiments (DoE) was used to understand each parameter's effects in the emulsions' characteristics and the statistical results. Each nanocellulose morphology presented a type of stabilization in emulsions and different ideal process parameters. CNC-emulsions showed as optimum parameters 30% essential oil and 7 minutes preparation, reflecting the higher necessary energy for the efficient CNCs adsorption in the O/W interface, and the maximum stability was ~ 50% by electrostatic interactions. CNF-emulsions showed optimum parameters 1% CNF and 12,000 rpm homogenization speed, reflecting the necessary parameters to convert the suspensions into gels where the droplets are well-coated by the fibers. This study is a pioneer in an in-depth understanding of the processing parameters' impact on emulsion stability and will be a guideline for future studies with different solid particles and oil phases.