Underwater electrical shockwave assisted CO2-responsive switchable hydrophilic solvent extraction of essential oil from pomelo peels

Abstract

The pomelo peels are rich in essential oils which have many beneficial effects. In this study, underwater electrical shockwave (UES) was successfully applied to the extraction and separation of essential oil from pomelo peels with CO₂-responsive switchable hydrophilic solvent (SHS) to eliminate the evaporation process of solvent removal after extraction and improve the extraction efficiency. Through the optimization of single-factor experiment and response surface methodology, the optimal process conditions were obtained as follows: the amine type of DMCHA, voltage of 3.1 kV, extraction time of 10.2 min and volume flow of 28 mL/min, and the maximum yield of essential oil was 72.26 ± 0.83 mg/g. Compared with traditional steam distillation and SHS maceration, UES-SHS extraction has a higher essential oil yield, lower energy consumption, shorter processing time, and a richer essential oil composition. Additionally, UES-SHS maintain the DMCHA recovery rate exceeding 75 % and an essentially unchanged essential oil yield over five extraction cycles, demonstrating sustainable development potential. Therefore, UES-SHS extraction is an energy-saving and efficient method, which has broad development prospects.