Effect of Ultrasonic Pretreatment on Yield and Properties of Essential Oil of Betel Leaf (Piper betle L.)

The goal of this research was to evaluate the ultrasound pretreatment affect the extraction of essential oil by hydrodistillation technique. In this study, betel leaves (Piper betle L.) were subjected to ultrasonic pretreatment (frequency: 28 kHz & 40 kHz; power: 150 W; duration 15, 30 and 45 min) prior to the essential oil extraction process. The resulting essential oil was then analyzed for its yield and properties, encompassing chemical composition, functional and morphological characteristics. The findings demonstrate that ultrasonic pretreatment substantially improved the extraction yield (0.18-0.22%) of the essential oil by 22.22%, as compared to conventional extraction methods. Since the application of ultrasonic waves facilitated the breakdown of cell walls, thereby promoting the release of essential oil constituents from the betel leaf matrix. Furthermore, the analysis of the essential oil revealed that ultrasonic pretreatment had a notable influence on its chemical composition. The treated samples exhibited percentage composition change of specific bioactive compounds such as Lemairamin (39.24-42.08%), Copaene (7.38-8.45%), hydrindane (23.95-21.91%). Moreover, the antioxidant activity of essential oil increased from 81.01 to 87.02% after the ultrasonic treatment. Furthermore, the effectiveness of ultrasonic pretreatment on the betel leaves for the extraction of essential oil was checked by scanning electron microscopy (SEM) analysis. Apart from this, power use (1.48-0.82 kWh) and environmental impact of CO2 emissions (1.17-0.68 kg) were also decreased during the extraction process for the treated betel leaves. Therefore, ultrasound pretreatment is an effective and environmentally friendly method of extracting betel leaves essential oils, which may increase the quantity and quality of betel leaves oils.