High-Pressure-Homogenized Clove and Thyme Oil Emulsions: Formulation, Stability, and Antioxidant Capacity

Abstract

This study focuses on the formulation of clove oil and thyme oil emulsions showing antioxidant capacity. Emulsions were formulated with 2 and 4% of each essential oil by using microfluidization. Tween 80 was used as the surfactant. Droplet sizes and polydispersity index values of emulsions were measured, and their effects on the emulsion stability were investigated. While thyme oil emulsions showed a good stability for 3 months, destability started in clove oil emulsions soon after homogenization due to Ostwald ripening. Stability results were parallel to the change of polydispersity index over time. Clove oil was found to be a more powerful antioxidant than thyme oil. It was also observed that clove oil emulsions had more antioxidant capacity than thyme oil emulsions. Total phenolic content results were in accordance with the antioxidant capacity results. The most significant observation of the study was the increase in droplet size of the clove oil emulsions followed by microfluidization due to the recoalescence phenomena.