Impact of toasting and botanical origin on oak wood (Q. sp.) volatilome using untargeted GCxGC-ToFMS analysis

The effects of climate change in viticulture are currently a major concern, with heat waves and drought affecting yield, wine quality, and in extreme cases, even plant survival. Ancient grapevine varieties have high intravarietal genetic variability that so far has been explored successfully to improve yield and must quality. Currently, there is little information available on intravarietal variability regarding responses to stress. In the current work, the intravarietal genetic variability of several Portuguese varieties was studied for yield, must quality, and tolerance to abiotic stress, through indirect, rapid, and nondestructive measurements carried out in the field.

Grape pomace (GP) is a winemaking by-product particularly rich in (poly)phenols and dietary fiber, which are the main active compounds responsible for its health-promoting effects. GP-derived products have been proposed to manage cardiovascular risk factors, including endothelial dysfunction, inflammation, hypertension, hyperglycemia, and obesity. Studies on the potential impact of GP on gut health are much more recent. However, it is suggested that, to some extent, this activity of GP as a cardiometabolic health-promoting ingredient would begin in the gastrointestinal tract as GP components (i.e., (poly)phenols and fiber) undergo extensive catabolism, mainly by the action of the intestinal microbiota, that gives rise to low-molecular-weight bioactive compounds that can be absorbed and utilized by the body.

Despite the numerous research studies carried out in recent years, the study of wine aroma remains of great interest due to its complexity. Wine maturation in oak barrels is described as an important step in the production of quality wines. In fact, oak wood develops several aromatic nuances through its toasting which can be released into the wine. A great deal of work has been performed in order to identify the wood-derived volatile compounds that contribute to wine aroma (e.g., whisky-lactone, maltol, eugenol, guaiacol, vanillin).

In a context of sustainable agriculture, “agroecological immunity” is an emerging concept to reduce the use of chemical pesticides to protect crops against pathogens. This alternative strategy aims to combine different levers including the use of “bio”solutions. These include biocontrol products, some of which being plant defense elicitors, as well as products authorized in organic farming such as copper or sulfur. In vineyards, depending on climate conditions, powdery and downy mildews can be devastating diseases.

Light is responsible for adverse reactions in wine including the formation of unpleasant flavors, loss of vitamins or photodegradation of anthocyanins. Among them, the riboflavin degradation leads to the formation of undesirable volatile compounds, known as light-struck taste. These photo-chemical reactions could be avoided by simply using opaque packaging. However, most rosé wines are kept in transparent bottles due to different commercial reasons. Some agri-food waste extracts have been studied for their photoprotective action which turn to be highly correlated with phenolic content [1].