Sustainable Delivery Systems: Retention of Model Volatile Oils Trapped on Hybrid Calcium Carbonate Microparticles

Transforming liquid active ingredients into solid, powdered materials is important for flavor and fragrance delivery, consumer, food, and beverage product technology, and pharmaceutical formulation. Liquid/powder blending is a sustainable technology to form liquid-loaded powders with a much lower energy input and no heating requirements as compared to heat-driven processes, such as spray-drying. The performance of wetted particles or agglomerates as delivery systems is limited because they typically remain open, without any protective barriers against loss of the liquid adsorbed on the surface and/or absorbed in the pores of the particles. Here, we investigate hybrid CaCO 3 microparticles precipitated in the presence of different amphiphilic additives and evaluate their capacity to trap and retain limonene, a model volatile oil, by adsorption on the particle surface. We show using a micrometer-scale analysis of localized wetting that a combination of surface area and chemical affinity of the carrier particle for the liquid is critical to control volatile losses. The specific surface area of the solid carrier particles alone is not a key parameter for good retention of volatiles in the liquid-loaded powders. Additionally, we investigate the role of highly hydrophobic, nonvolatile solvents on volatile evaporation. This study demonstrates a sustainable processing approach to form delivery systems for volatile active ingredients.