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

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. (C) 2017 Elsevier Ltd. All rights reserved.