Macrowine 2021
IVES 9 IVES Conference Series 9 HEAT BERRY : Sensitivity of berries ripening to higher temperature and impact on phenolic compounds in wine

HEAT BERRY : Sensitivity of berries ripening to higher temperature and impact on phenolic compounds in wine

Abstract

The grapevine is an important economical crop that is very sensitive to climate changes and microclimate. The observations made during the last decades at a vineyard scale all concur to show the impact of climate change on vine physiology, resulting in accelerated phenology and earlier harvest (Jones and Davis 2000). It is well-known that berry content is affected by the ambient temperature. While the first experiences were primarily conducted on the impact of temperature on anthocyanin accumulation in the grape, few studies have focused on others component of phenolic metabolism, such as tannins. Due to their chemical structure they are involved in the sensation of astringency / bitterness and play a key role in the quality of wines (Downey, Dokoozlian, and Krstic 2006). In a context of climate change and global warming, it is necessary to ask the question of the effect of temperature on the metabolism and its impact on wine quality. One of the goals of the HEAT BERRY project is to understand the physiological basis of the response of secondary metabolism to heat and microclimate, in grape berries, and their resulting effects on wine chemistry and organoleptic properties. A passive heating system made of polycarbonate screens has been set up at the vineyard. Field experiments conducted on Cabernet Sauvignon showed that this system induces 1 to 3°C increase in berry temperature. The heating system was set up in June at fruit set, and berries juices were sampled and used for ripening analysis between veraison and harvest time. The results of ripening agreed with previous studies: phenolic maturity and extractability of anthocyanins were decreased on heated berries. Nowadays, it is well-known that tannins nature within different berry tissues has an impact on bitterness and astringency (skins tannins mainly participate to the sensation of astringency, while seeds tannins also contribute to bitterness) as well as the percentage of each berry part. But nothing was shown about the importance of a temperature increase on these aspects. Microvinifications were performed on ripe (and over-ripe) berries. First, tastings demonstrated significant differences between wines from heated berries and non-heated berries in accordance with ripening process and berry compounds. Second, phenolics compounds (tannins levels, Dpm, tannins composition) were analyzed in berries and in wines. The analytical results will be compared with the sensory analysis in order to better understand the qualitative impact of heat treatment on berries and wine properties. Overall, the aim of HEAT BERRY is to address the poor knowledge of the effects of high temperatures on berry composition and wines. This should provide useful clues for the adaptation of viticulture to climate change.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Article

Authors

Julie Drappier*, Cécile Thibon, Darriet Philippe, Jing Wu, Laurence Geny-Denis, Michael Jourdes, Philippe Pieri, Robin Rabagliato, Serge Delrot

*ISVV

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Interest and impact of PVP/PVI (Polyvinylpyrrolidone/ Polyvinylimidazole) on winemaking and final quality of wines

Céline Sparrow a, Christophe Morge a, a SOFRALAB SAS, 79, av. A.A. Thévenet – CS 11031 – 51530 Magenta, France Consumers’ health and security force authorities to limit, in wine as in others food industry products, the concentration in « dangerous » molecules. Therefore the legal limit in heavy metals keeps on decreasing. As per proof EU regulation just decrease the stain concentration in wine from 0,2 to 0,15 mg/l. Certain changes , such as sodium arsenite treatment in vines, disappearance of brass in wineries to the benefit of stainless steel, limit even more the concentration of heavy metals in wines. But the use of copper derivates in vines treatments is difficult to replace. In the case of wine and its elaboration, the problem is even more complex. Indeed, regulation forces the wine producers to control the concentration of certain heavy metals in final wines.

The influence of soil management practices on functional traits and biodiversity of weed communities in Swiss vineyards

Green cover in vine rows provides many ecological services, but can also negatively impact the crop, depending on the weed species. The composition of a vineyard weed community is influenced by many parameters. Ensuring an evolution of the vine row flora into a desired direction is therefore very complex. A key step towards this goal is to know which factors influence the establishment of the weed community and which types of communities are best suited for vineyards. In this study, we analysed the weed communities of several vineyards in the Lake Geneva region (379 botanical surveys on 117 plots), with the aim to highlight the links between soil management practices (chemical and mechanical weeding, mowing, mulching roll) and phytosociological profiles, biodiversity and selected functional traits (growth forms, life strategies, root depth). T

On the losses of dissolved CO2 from laser-etched champagne glasses under standard tasting conditions

Under standard champagne tasting conditions, the complex interplay between the level of dissolved CO2 found in champagne, its temperature, the glass shape, and the bubbling rate, definitely impacts champagne tasting by modifying the neuro-physico-chemical mechanisms responsible for aroma release and flavor perception. Based on theoretical principles combining heterogeneous bubble nucleation, ascending bubble dynamics and mass transfer equations, a global model is proposed (depending on various parameters of both the wine and the glass itself), which quantitatively provides the progressive losses of dissolved CO2 from laser-etched champagne glasses.

Anti/prooxidant activity of wine polyphenols in reactions of adrenaline auto-oxidation

Adrenaline (epinephrine) belongs to catecholamine class. It is a neurotransmitter and both a hormone which is released by the sympathetic nervous system and adrenal medulla in response to a range of stresses in order to regulate blood pressure, cardiac stimulation, relaxation of smooth muscles and other physiological processes. Adrenaline exhibits an effective antioxidant capacity (1). However, adrenalin is capable to auto-oxidation and in this case it generates toxic reactive oxygen intermediates and adrenochrome. Under in vitro conditions, auto-oxidation of adrenaline occurs in an alkaline medium (2).

The use of cation exchange resins for wine acidity adjustment: Optimization of the process and the effects on tartrate formation and oxidative stability

Acidity adjustments are key to microbial control, sensory quality and wine longevity. Acidification with cation exchange resins -in acid cycle- offers the possibility to reduce the pH by exchanging wine cations, such as potassium (K+), for hydrogen ions (H+). During the exchange process, the removal of potassium and calcium ions contributes to limiting the formation of tartrate salts, thus offering an alternative solution to conventional methods for tartrate stability. Moreover, the reduction of wine pH and the removal of metals catalyzers (e.g. iron) could positively impact the wine’s oxidative stability. Therefore, the aims of this work were (a) to optimize the ion exchange process by testing different volumes and concentrations of sulfuric acid (H2SO4) during the acid cycle, (b) evaluate the effects of the ion exchange process on the formation of tartrate salts, and (c) analyze the oxidative stability of the treated wines.