Pulsed Electric Fields – assisted vinification

Abstract

Pulsed Electric Fields (PEF) treatments can be profitably applied as pretreatment to the extraction process from vegetable tissues, in order to increase the release of valuable compounds. In the present work we propose to apply PEF treatments during the vinification process for the permeabilization of the grape skins, in order to increase the polyphenolic content after maceration of red wines made from four Italian grape varieties, Aglianico, Piedirosso, Nebbiolo and Casavecchia. Prior to the fermentation/maceration step, the grape skins were treated at different PEF intensities (field strengths of 1.5 and 3.0 kV/cm and energy inputs of 10 and 20 kJ/kg), with their permeabilization being characterized by electrical impedance measurements. The fresh wine, obtained after pressing, was characterized for alcohol content, total acidity, pH, color intensity, total polyphenols, anthocyanins content and antioxidant activity.PEF treatment on Aglianico grapes induced a significantly higher release of polyphenols (+100%) and anthocyanins (+30%), thus improving the color intensity (+20%) and the antioxidant activity of the wine (+40%), while preserving the other organoleptic characteristics. Similar results were obtained over two different harvest years (2008 and 2009), confirming the repeatability of the process. In contrast, there was only a minor impact on the polyphenolic release kinetics of Piedirosso, Nebbiolo and Casavecchia grapes, despite the significant degree of cell membrane permeabilization, with it probably being due to the predominance of mass transfer limitations through the vacuole membrane

Evolution of Polyphenolic Compounds and Sensory Properties of Wines Obtained from Grenache Grapes Treated by Pulsed Electric Fields during Aging in Bottles and in Oak Barrels

“…Improving the degree of extraction of polyphenols during the maceration-fermentation stage of red winemaking has been one of the most widely investigated applications of pulsed electric fields (PEF) in recent years. Several research groups working with different grape varieties have demonstrated that a PEF treatment applied to grapes before the maceration-fermentation stage allows for a reduction of the contact time of grape skins with the fermenting must, or helps to obtain wines with higher polyphenolic content [2][3][4][5][6]. This effect is attributed to a phenomenon called electroporation, which involves an alteration of cell membrane permeability as a consequence of the application of an external electric field [7].…”

Impact of a combined pulsed electric field (PEF) and enzymatic mash treatment on yield, fermentation behaviour and composition of white wine

“…López-Giral et al [20] found an increase in the content of specific polyphenols such as gallic acid (24%), caffeic acid (48%) and rutin (141%) after PEF pretreatment of red grapes of different varieties. A comparison of enzyme treatment and PEF treatment with regard to the impact on the extraction process was done by Donsì et al [21] and revealed that for some of the investigated varieties, the enzyme treatment showed more pronounced effects. In contrast, Puértolas et al [22] stated that the extraction of phenolic compounds from red grape mash after PEF treatment was more effective than the addition of enzymes.…”

The bioactive compounds, antioxidant capacity, and color intensity in must and wines derived from grapes processed by pulsed electric field

“…Non-antioxidant compounds in wine (amino acids, uronic acids) may cause interferences and influence the estimated values of antioxidant capacity. Donsì et al (2011) have evaluated the effect of PEF treatment applied to four varieties of grapes in Italy in respect to antioxidant activity (by DPPH method) and have obtained a wine with a high antioxidant capacity (+40%).…”

“…The use of pulsed electric field (PEF) has been studied in specialized literature, leading to the conclusion that it contributes to increased efficiency due to the combination of the pressure effect and electroosmosis (Delsart et al, 2014;Donsì, Ferrari, Fruilo, & Pataro, 2011;GardeCerdán et al, 2013;Puértolas, López, Condón, Álvarez, & Raso, 2010a). PEF technology as a pretreatment step in winemaking technology has great potential in microbial control in wines.…”