Optimization of ultrasonic Bath and cold plasma pre‐treatments in the spearmint essential oil isolation process

Abstract

Spearmint essential oil (SEO), one of the economically valuable natural products, has special importance in the food, pharmaceutical, and perfumery industries due to its antifungal, antioxidant, and enzyme inhibitory properties. In this study, we optimized and evaluated the effect of three pre‐treatments on the extraction of SEO for quantity and quality: ultrasonic bath (UB), water to material ratio‐ultrasonic bath (W/M‐UB), and cold plasma‐ultrasonic bath (CP‐UB). Three experiments were designed using the central composite design (CCD) of response surface methodology (RSM). Experimental treatments included UB temperature (30–80°C) and time duration (1–30 min), cold plasma (CP) power (15–24 kV), and water/material ratio (10–40). Then, SEOs were extracted by hydro‐distillation using the Clevenger apparatus. The results showed that SEO yield in the optimal conditions of treatments was 119.7%, 206.6%, and 155.7% higher in UB, W/M‐UB, and CP‐UB pretreatments respectively, in comparison to control sample and optimized conditions were UB temperature: 37.3°C and UB time: 5.2 min at UB treatment, 33.9 of W/M ratio, 69.9°C of UB temperature and 6.9 min of UB time at W/M‐UB treatment and CP power: 22.176, UB temperature: 40.135 and UB time: 24.122 at CP‐UB treatment. Oxygenated monoterpenes were also higher in the essential oils (EOs) of all three treated plant materials. In conclusion, the SEO extraction yield improved by the application of the pretreatments in optimized conditions.

Steps to achieve carvone-rich spearmint (Mentha spicata L.) essential oil: a case study on the use of different distillation methods

“…The yield and chemical composition of EOs can be impacted by the various extraction methods and treatments. For example, cold plasma and ultrasound pre-treatments can increase SEOs yield and oxygenated monoterpenes (Moradi-Sadr et al, 2023). Also, it has been verified that MAHD has the potential to improve oxygenated compounds, reduce energy consumption (Drinićet al, 2021), speed up the extraction process, and increase the amount of extracted EO (Yu et al, 2021;Thinh et al, 2022).…”