Pulsed Electric Fields – assisted vinification of Aglianico and Piedirosso grapes

Pulsed Electric Fields (PEF) treatments were applied to increase the polyphenolic content of fresh red wines made from Aglianico and Piedirosso grapes. Prior to the fermentation/maceration step, the grape skins were treated at different PEF intensities (field strengths from 0.5 to 1.5 kV/cm and energy inputs from 1 to 50 kJ/kg), with their permeabilization being characterized by electrical impedance measurements. Furthermore, the release kinetics of the total polyphenols and anthocyanins were characterized during the maceration stage by spectroscopic and Folin-Ciocalteau colorimetric methods, respectively. Finally, the fresh wine, obtained after pressing, was characterized for total acidity, pH, reducing sugar, color intensity, total polyphenols, anthocyanins content, antioxidant activity and volatile compounds composition. PEF treatment on Aglianico grapes induced a significantly higher release of polyphenols (+20%) and anthocyanins (+75%), thus improving the color intensity (+20%) and the antioxidant activity of the wine (+20%), while preserving the other organoleptic characteristics. In contrast, there was only a minor impact on the polyphenolic release kinetics of Piedirosso grapes, despite the significant degree of cell membrane permeabilization