Unlocking the bioactive potential of Ocimum selloi: how drying temperature shapes antioxidant efficacy

Ocimum species, particularly Ocimum selloi Benth, popularly known as atroveran, are notable for their significant biological properties and wide applicability in pharmaceutical, food, and cosmetic industries. This study aimed to evaluate the effects of drying air temperature and velocity on the drying kinetics of O. selloi leaves in a fixed-bed dryer and to identify the most suitable mathematical model to describe the process. Following drying, ethanolic and aqueous extracts were prepared from the leaves and analyzed for antioxidant activity. The results showed that air velocity had a limited effect on the drying rate. Among the tested models, the Midilli et al. (2002) model provided the best fit to the experimental data across the temperature range of 40 to 60 °C. Ethanolic extracts demonstrated superior yield and biological activity compared to aqueous extracts. Additionally, lower drying temperatures contributed to the preservation of antioxidant compounds, resulting in extracts with higher antioxidant activity. These findings support the optimization of drying conditions aimed at preserving the functional properties of medicinal plants.