Essential oils (EOs) are widely used in various industrial sectors but can present several instability problems when exposed to environmental factors. Encapsulation technologies are effective solutions to improve EOs properties and stability. Currently, the encapsulation in lipid nanoparticles has received significant attention, due to the several recognized advantages over conventional systems. The study aimed to investigate the influence of the lipid matrix composition and spray-drying process on the physicochemical properties of the lipid-based nanoparticles loaded with Lippia sidoides EO and their retention efficiency for the oil. The obtained spray-dried products were characterized by determination of flow properties (Carr Index: from 25.0% to 47.93%, and Hausner ratio: from 1.25 to 1.38), moisture (from 3.78% to 5.20%), water activity (<0.5), and powder morphology. Zeta potential, mean particle size and polydispersity index, of the redispersed dried product, fell between −25.9 mV and −30.9 mV, 525.3 nm and 1143 nm, and 0.425 and 0.652, respectively; showing slight differences with the results obtained prior to spray-drying (from −16.4 mV to −31.6 mV; 147 nm to 1531 nm; and 0.459 to 0.729). Thymol retention in the dried products was significantly lower than the values determined for the liquid formulations and was affected by the drying of nanoparticles.

A quality by design approach was used to investigate the influence of formulation composition and spray drying conditions on physicochemical properties of redispersable lipid based nanosystems loaded with Syzygium aromaticum essential oil. Four critical independent variables were studied: presence or absence of the liquid lipid oleic acid (0% -1%), of the cationic surfactant CTAB (0% and 1%), inlet drying temperature (60 ºC -80 ºC), and ratio of the drying aids (ADJ) regarded to total formulation constituents weight (1:1 and 2:1). Resuls showed the production of spray dried redispersable lipid systems loaded with essential is feasible under very restrict conditions.