Extraction of essential oils from Kumquat peel using ultrasound‐assisted vacuum hydrodistillation

In the current study, ultrasound-assisted vacuum extraction (UAVE) was applied to improve the efficiency of hydrodistillation extraction (HDE) and vacuum hydrodistillation extraction (VHE) and produce Kumquat peel essential oil (EO) with acceptable quality. To achieve these objectives, the effects of ultrasound power (210–300 W), ultrasound time (15–40 min), and pressure (600–900 mbar) were evaluated. Results showed that the EO yield initially increased and then decreased with increasing ultrasound power, ultrasound time, and pressure, and the highest EO yield was achieved at 270 W, 20 min, and 800 mbar. The EO obtained by UAVE under conditions allowed a higher EO yield than VHE and less extraction time than HDE, and provided EO with higher antioxidant activity due to differences in chemical composition. Overall, the application of UAVE could be an effective approach to improve the extraction efficiency and quality of the Kumquat peel EO. Novelty impact statement Ultrasound-assisted vacuum hydrodistillation was applied to extract essential oil (EO). A comparative study on the ultrasound-assisted vacuum hydrodistillation extraction. Ultrasound-assisted vacuum hydrodistillation improved the antioxidant activity of EO.