Functionality of commercial tannins: anti-Botrytis effect, antioxidant capacity and organoleptic impact

Autor: Fermaud, Marc, Gancel, Anne-Laure, Vignault, Adeline, Pilard, Etienne, Jourdes, Michaël, Roudet, Jean, Zamora, Fernando, Teissèdre, Pierre-Louis
Přispěvatelé: Santé et agroécologie du vignoble (UMR SAVE), Université de Bordeaux (UB)-Institut des Sciences de la Vigne et du Vin (ISVV)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), FERMAUD, MARC
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: 41ème Congrès Mondial de la Vigne et du Vin
41ème Congrès Mondial de la Vigne et du Vin, Nov 2018, Punta del Este, Uruguay
Popis: International audience; Grey mould caused by Botrytis cinerea is one of the most serious diseases affecting grapevine (Vitis vinifera L.) in temperate area. It induces chemical changes that have damageable effects on wine quality, especially color degradation. Indeed B. cinerea excretes enzymes like laccases able to turn phenolic compounds from grape berries into quinones leading to a possible oxidasic casse, unacceptable in terms of product quality. Even a low contamination degree (5%) can lead to a perceptible loss of wine sensory quality [1]. Beside manual selection of healthy grape clusters, few eco-responsible alternatives to SO2 are proposed to treat laccases. Commercial tannins, already authorized by OIV for fining, are interesting candidates as they have also antioxidant and antioxidasic properties. However, very few scientific or technical papers are available on the subject [2]. Therefore, we studied here commercial tannins as a possible alternative to SO2 at the vatting.Five tannins were chosen from different vegetal sources: procyanidins from seed (TPA) (low mPD) and skin (IE) (high mPD) of grape berries, profisetinidins from quebracho tropical tree (T), ellagitannins from oak tree (Q) and gallotannins from nutgall (G). Musts with 20 % and 50% botrytization rates were obtained from healthy and botrytized grapes (strain 213) from Merlot cultivar. High contamination degrees were chosen to reveal contrasted effects. The impact of commercial tannins addition at the vatting (100 g/hL) on musts and wines protection against laccase damages was studied with regards to the laccase activity, antioxidant capacity, phenolic compounds composition and CieLab color parameters. Sensory analyses were also performed on 3 month-wines to evaluate visual, olfactory and gustative impacts of tannins additions. Results showed that at 50% botrytisation rate, the addition of any type of commercial tannins at 100 g/hL seemed to be ineffective on laccase activity and phenolic compounds protection. Laccase activities > 5 U/mL were found in 3 month wines leading inevitably to oxidasic casse. Despite this high botrytisation rate, calculated color differences (E) and sensory analyses showed differences between tannins: wines obtained with IE and G tannins were darker than the control wine whereas wine with Q tannins was lighter. At a 20% botrytisation rate, differences between tannins addition were more evident. Procyanidic tannins from IE or TPA showed an inhibitory effect on laccase activity and protected color against complete degradation. Moreover, wine with IE tannins appeared to be darker and perhaps more qualitative with regards to olfactory and gustative aspect than the control wine.
Databáze: OpenAIRE
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