Impact of Three-Fluid Nozzle Emulsification on the Physicochemical and Thermodynamic Properties of Avocado Oil Microcapsules Obtained by Spray Drying

This study investigated the production and characterization of avocado oil emulsions generated with a three-fluid nozzle (3FN) and the physicochemical and thermodynamic properties of the resulting microcapsules obtained by spray drying. The emulsions showed a bimodal size distribution with a main peak at 0.893 µm and PDI values below 0.70 indicate a mid-range polydispersity. Despite their shear-thinning behavior, emulsions exhibited limited stability, as indicated by ζ-potential (−23.9 mV) and increasing TSI values. Spray drying with 3FN achieved a yield of 71.7% and an encapsulation efficiency of 57.8%, with moisture content below 4%, meeting commercial requirements. The microcapsules displayed unimodal particle distributions (D[3,2] = 8.38 µm; D[4,3] = 11.14 µm) and irregular spherical morphologies with surface folds and roughness. Adsorption isotherms followed a type II pattern, well described by the GAB model, with monolayer moisture content (0.043–0.060 g H2O/g solids) defining critical stability conditions. Thermodynamic analyses identified a “minimum entropy zone” corresponding to enhanced structural stability, while glass transition data confirmed that encapsulated oil did not act as a plasticizer. Overall, the use of a three-fluid nozzle enabled the development of avocado oil microcapsules with favorable physical and thermal attributes, supporting their potential for long-term stability in functional food applications.