Enological tannins affect acetaldehyde evolution, colour stability and tannin reactivity during forced oxidation of red wine

Abstract

SummaryThe addition of enological tannins is a practice admitted and widely used to improve wine phenolic compositions. Although wine ageing is an oxidative process involving phenolic compounds and acetaldehyde production and consumption, the effect of enological tannins on the acetaldehyde and chromatic and phenolic changes of a red wine during oxidation is still not known. In this study, three enological tannins preparations containing gallotannins GT, ellagitannins ET and condensed tannins CT were added to a young commercial Lambrusco red wine in order to obtain wines with three different phenolic compositions. Samples were then treated with hydrogen peroxide to trigger oxidation. All added tannins have determined a production of acetaldehyde greater than control. Acetaldehyde was then consumed in 30 days. The samples treated with CT and ET showed, after oxidation, an increase in colour intensity, determined as the sum of 420, 520 and 620 nm absorbances. A simultaneously increase in polymeric pigments was detected. No significant variation of the Saliva Precipitation Index (SPI), an index useful to give an indirect measure of wine astringency, was observed after 30 days of treatment of CT and ET samples. Results highlight that the addition of CT and ET can help to stabilise colour without affecting wine reactivity towards salivary proteins. A significant role of acetaldehyde has been even detected. These are the first data showing the effect of different enological tannins on the production and consumption of acetaldehyde formation during an oxidation process.

Fermentative and post‐fermentative oxygenation of Corvina red wine: influence on phenolic and volatile composition, colour and wine oxidative response

“…These trends are consistent with the notions that anthocyanins accumulate progressively as maceration progresses, but they are quickly degraded in reactions with quinones produced in the first stages of oxidation from ortho ‐diphenols as well as with acetaldehyde when present . As a result, complex polymeric pigments involving adducts of anthocyanins with flavanols mediated by acetaldehyde are formed . In agreement with these observations, under our experimental conditions, polymeric pigments accumulated to a greater extent in oxygen‐treated wines, but only after day 10.…”

“…50 As a result, complex polymeric pigments involving adducts of anthocyanins with flavanols mediated by acetaldehyde are formed. [51][52][53] In agreement with these observations, under our experimental conditions, polymeric pigments accumulated to a greater extent in oxygen-treated wines, but only after day 10. Thus, it is likely that higher amounts of acetaldehyde and other oxidation products led to a greater conversion of anthocyanins to stable pigments.…”

Effect of different levels of skin disruption and contact with oxygen during grape processing on phenols, volatile aromas, and sensory characteristics of white wine

“…Benzoic acids, flavanols, flavonols, and flavononols are found in white grape skins and seeds, while hydroxycinnamic acids are the main phenols of pulp (Di Lecce et al, ). Besides other approaches, such as, various ampelotechnical measures to affect grape berry light and temperature exposure, water stress, and also variation in harvest date, as well as various procedures during winemaking and storage (Delgado Cuzmar et al, ; Harrison, ; Picariello, Gambuti, Petracca, Rinaldi, & Moio, ), manipulating the interaction between grape skins and juice during pre‐fermentation processing steps is a crucial strategy for determining the content of phenols in white wine, since during skin contact phenols diffuse from skins and other solids into juice. Pre‐fermentation processing phases are also critical because of the high rate of oxygen consumption which can induce undesirable changes, such as phenol oxidation and the reduction of wine mouthfeel and color quality (Antonelli, Arfelli, Masino, & Sartini, ).…”

“…measures to affect grape berry light and temperature exposure, water stress, and also variation in harvest date, as well as various procedures during winemaking and storage (Delgado Cuzmar et al, 2018;Harrison, 2018;Picariello, Gambuti, Petracca, Rinaldi, & Moio, 2018), manipulating the interaction between grape skins and juice during pre-fermentation processing steps is a crucial strategy for determining the content of phenols in white wine, since during skin contact phenols diffuse from skins and other solids into juice.…”

Carbonyl compounds in wine: factors related to presence and toxic effects

“…During wine oxidation, iron (II) reduces oxygen to the hydroperoxyl radical, which converts wine hydroquinones into quinones and hydrogen peroxide (H 2 O 2 ). Ferrous ion associated to H 2 O 2 generates hydroxyl radical that can react with ethanol to yield acetaldehyde (PICARIELLO et al, 2017).…”