Pulsed electric fields and high-voltage electrical discharges-assisted extraction of valuable biocompounds and biopolymers from rapeseed by-products

Abstract

This chapter presents the most recent advances in the conversion of rapeseed residues into valuable molecules. After a brief description of the lignocellulosic biomass biorefinery concept and its current state of art, the contents are then divided into different sections, according to the valorized residues. The use of electrotechnologies covers the bulk of the chapter. Studies focusing on isothiocyanate, polyphenol, and protein extraction from rapeseed steams, leaves, seeds, and cake have been respectively exposed. It was highlighted as a significant increase in polyphenol (≈5-fold) and protein (≈2-fold) content from pulsed electric fields (PEF)-pretreated samples under the optimum conditions (8 kV/cm, 2 ms, 10 bar) compared to the untreated ones. The potential of highvoltage electric discharges (HVED) (40 kV, 0-400 kJ/kg) to extract proteins, polyphenols, and isothiocyanates from seeds and cake obtained after oil extraction has also been demonstrated. The extraction of higher molecular weight molecules has also been studied. Indeed, delignification of rapeseed straws and hulls seemed to be improved thanks to a previous electric pretreatment step to the chemical pretreatment. An increase by 8% and 5% of delignification yields was observed from rapeseed hulls using HVED and PEF, respectively.