Continuous extraction of phenolic compounds from pomegranate peel using high voltage electrical discharge

•A continuous HVED extraction system was designed for the first time.•Response surface methodology was used to optimize the process variables.•The optimal conditions were: 12 mL/min, 3.1 mm and 35 mL/g.•The predicted yield of phenolic compounds was 199.83 mg/g.•The experimental values were in close agreement with predicted values.

Pomegranate peel, a waste generated from fruit processing industry, is a potential source of phenolic compounds that are known for their anti-oxidative properties. In this study, a continuous high voltage electrical discharge (HVED) extraction system was for the first time designed and optimized for phenolic compounds from pomegranate peel. The optimal conditions for HVED were: flow rate of materials 12 mL/min, electrodes gap distance 3.1 mm (corresponding to 29 kV/cm of electric field intensity) and liquid to solid ratio 35 mL/g. Under these conditions, the experimental yield of phenolic compounds was 196.7 ± 6.4 mg/g, which closely agreed with the predicted value (199.83 mg/g). Compared with the warm water maceration, HVED method possessed higher efficiency for the extraction of phenolic compounds. The results demonstrated that HVED technique could be a very effective method for continuous extraction of natural compounds.