Neural networks and ft-ir spectroscopy for the discrimination of single varietal and blended wines. A preliminary study.

In this video recording of the IVES science meeting 2023, Sara Bernardo (CITAB, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal) speaks about understanding vine response to Mediterranean summer stress for the development of adaptation strategies – in the kaolin case. This presentation is based on an original article accessible for free on OENO One.

Climate change poses significant challenges for viticulture, particularly in Mediterranean regions like Portugal, where extreme heat and drought conditions are becoming more frequent.

Wine lees are quantitatively the second most important wine by-product after grape stems and marc [1]. In order to recycle, distilleries recovered ethanol and tartaric acid contained in wine lees but yeast biomass is often unused. It has already been demonstrated that this yeast biomass could be upcycled to produce yeast extracts of interest for wine chemical stabilization [2]. In addition, it is well known that lees, during aging, release compounds that preserve wine from oxidation.

Syrah is a grape with weak aromatic expression. This atypical grape variety as a fruit allows the production of wines of great reputation for which the aromatic particularity plays an important role. The varietal aroma consists of volatile substances directly perceptible by the olfactory mucosa and of aroma precursors, of which the glycosides constitute an important class.

From the effect of global climate change, wildfire occurrence during grape ripening has increased. These wildfires produce smoke that can carry organic compounds to a vineyard. These smoke compounds are adsorbed in the grape berry and result in wines with elevated levels of smoke-related phenols. These wines are described as having a smokey, burnt, and dirty aroma (Kristic et al, 2015). Not only are volatile phenols carried by smoke, but additionally glycoconjugate forms of these phenols are present as will. These have been found to have a large impact on the flavor of wines, being the cause of a lasting ashy aftertaste post consumption (Parker et al, 2012). When evaluating the sensory profile of these wines when tasted one after the other, there is an observed problem due to the lasting nature of these undesirable attributes and high level of carry-over from sample to sample. The aim of this work is to evaluate the extent this carryover occurs, along with the best sensory practices to mitigate its influence via different inter-stimulus rinse protocols.