Enhancing the quality attributes of mint medicinal plant (Mentha spicata L.) through simultaneous combined ozone and infrared drying

Medicinal plants are widely used in various traditional and modern medical methods due to their therapeutic properties. Drying is a common method used to preserve the biochemical compounds of medicinal plants. Still, conventional drying methods can lead to the loss of active compounds due to exposure to high temperatures. This research aimed to design and construct an ozone generator for use in a combined dryer and evaluate the ozone, temperature, and hot air flow rate on the quality properties of mint (Mentha spicata L.). Drying experiments were conducted at varying temperatures, air flow speeds, and ozone levels. Results indicated that increasing temperature reduced total phenol and flavonoid content while increasing antioxidant capacity. Higher airflow speed positively influenced total phenol, total flavonoid content and antioxidant potency but reduced drying time. Ozone exposure increased total phenol, flavonoid content, antioxidant activity, and had minimal effect on drying time. Optimization revealed that a temperature of 52.47degree celsius, air flow rate of 1.5 m/s, and 90.37% ozone concentration yielded favorable outcomes, including enhanced phenolic and flavonoid content, antioxidant power, and decreased energy consumption. Compared to other drying methods, the proposed ozone-enhanced method proved superior in preserving bioactive compounds and maintaining a reasonable drying time. Overall, the research highlights the potential of ozone-assisted drying for optimizing the quality of medicinal plants during preservation.