Potential use of pulsed electric technologies and ultrasounds to improve the recovery of high-added value compounds from blackberries

Abstract

A better knowledge of the effect of non-conventional extraction technologies, which can avoid the use of high temperatures and toxic solvents, on the antioxidant compounds recovery from blackberries, is necessary. Thus, high voltage electrical discharges (HVED), pulsed electric fields (PEF), and ultrasounds (USN) treatments were applied in order to evaluate the effects of processing on protein, total phenolics and anthocyanins extraction from blackberries. Moreover, two-stage extraction involving the use of HVED, PEF and USN as pre-treatments and supplementary extraction during 5h with hot water at mild temperature (50°C) or an hydroalcoholic solution (30% ethanol, w/w) was evaluated. The impacts of both hot water (50°C) and ethanol had a positive influence in total phenolics and anthocyanin recovery, although the yield was clearly influenced by the treatment applied and the targeted compound. The highest protein (37.95±1.30mg/100g) and TPC (932.69±33.45mg/100g) yields were obtained after HVED and supplementary extraction during 5h, using ethanol and hot water at 50°C, respectively. However, the maximum anthocyanin yield (98.46±4.92mg/100g) was found after applying PEF treatment and supplementary extraction with hot water at 50°C. These promising findings open the doors to a potential multi-stage green recovery, which can improve the selectivity and the amount of high-added value compounds recovered.