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.