Abstract
In recent years, Pulsed Electric Field (PEF) technology has been developing in laboratories and is starting to be established in the industry, mainly in the agri-food sector. So far all experimentations on the use of PEF in the wine industry was carried out at the laboratory scale on some kilograms of grapes, or liters of wines. Since 2015, we are studying the interest of the use of PEF on grape polyphenols extraction on a semi-industrial scale of 2 tons per hour. The first tests were carried out by comparing the PEF technology to a control, and a conventional thermovinification with liquid phase vinification and traditional vinification with different fermentation times. The first results obtained are encouraging. Vinified in the liquid phase, the grapes treated with PEF give wines with a color intensity of 20 to 30% higher than the control and a higher TPI of 7 to 17%. In the liquid phase, the treatment of the harvest by PEF does not make it possible to obtain the extraction level of the thermovinification. After a short maceration of 3 days, the polyphenols extraction level is similar to the thermovinification, and greater after 14 days, and so is the color (respectively +12 and +16%). No change in IBMP content was observed. The wines resulting from treatment of the harvest by PEF do not have the aromatic profile of thermovinification wines. The PEF has a fruity character comparable to the control and accentuates the aromatic characteristics of the grape variety. The wine are often judged less aggressive and astringent by reinforcing the perception of sweetness and full bodied. A few tests in white grape harvest by PEF, shows a significant gain of the thiols and terpenols.
Highlights
Depuis quelques annees, l’utilisation de Champs Electriques Pulses (CEP) est experimentee dans la filiere œnologique [1, 2] avec pour objectif d’ameliorer l’extraction des polyphenols lors de la vinification en rouge [3, 4], et d’assurer la stabilitemicrobiologique des mouts [5, 6] et des vins [7].Jusqu’ici, presque toutes ces experimentations etaient realisees en condition de laboratoire [8, 9] sur quelques kilogrammes de raisins ou quelques litres de vin tout au plus
L’extraction d’azote ammoniacal et surtout αaminee est egalement amelioree (6 a 24 %) dans les modalites traitees par les CEP
Le gain en IPT est superieur de 30 % entre le CEP 3 jours et 14 jours de maceration
Summary
L’utilisation de Champs Electriques Pulses (CEP) est experimentee dans la filiere œnologique [1, 2] avec pour objectif d’ameliorer l’extraction des polyphenols lors de la vinification en rouge [3, 4], et d’assurer la stabilitemicrobiologique des mouts [5, 6] et des vins [7]. La technique des CEP est basee sur l’application d’un champ electrique haute tension (0.3–80 kV/cm) sous forme de courtes impulsions [10, 11] de quelques microsecondes (μs), aplusieurs millisecondes (ms) ades frequences variables [12], conduisant ala permeabilisation des cellules [13, 14] (electro-poration) avec un chauffage minimum du produit. En fonction des caracteristiques du champ electrique (tension et durees des impulsions principalement, et nombre d’impul-sions recues), la formation des pores peut etre reversible, permettant ainsi l’extraction des composes intra cellulaires d’interet, ou irreversibles conduisant au vidage total du contenu cellulaire, et la mort de la cellule microbienne (stabilitemicrobiologique). Parametres Tension de travail Duree des impulsions Type d’impulsions Polaritedes impulsions Duree entre impulsions Frequence des impulsions
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