Continuous high voltage electrical discharge extraction of flavonoids from peanut shells based on “annular gap type” treatment chamber

A continuous high voltage electric discharge (HVED) extraction system with “annular gap type” treatment chamber was for the first time designed and optimized for flavonoids extraction from peanut shells, and a comparison with the HVED system with the “converged electric field type” treatment chamber and warm maceration was carried out. The optimal conditions for the “annular gap type” design were: 25% ethanol concentration as solvent, 30:1 mL/g liquid to solid ratio, 13 kV peak pulse voltage and 60 mL/min flow rate of material. Under these conditions, the maximum yield of flavonoids was 0.948 ± 0.014%. Compared with the “converged electric field type” design and warm maceration, the “annular gap type” design possessed shorter duration and higher efficiency for the flavonoids extraction, and had no effects on the composition of extracted flavonoids. The results showed that the “annular gap type” design was a promising alternative method in extracting flavonoids from peanut shells.