Les activités peroxidasiques du raisin de quelques cépages de Roumanie

Grapevines are susceptible to freezing damage at temperatures below -5°F during the winter season. Preventing winter injury to grapevines is a major challenge in many grape-producing regions. Conventional methods such as hilling-up soil over graft unions have been developed as winter protection methods for preventing vine loss. However, these practices have drawbacks such as soil erosion, vine damage and crown gall development.

Grape pomace is one of the main by-products generated after pressing in winemaking.Emerging methods, such as ultrasound-assisted extraction with eutectic mixtures, have great potential due to their low toxicity, and high biodegradability. Choline chloride (ChCl) was used as a hydrogen bond acceptor and its corresponding hydrogen bond donor (malic acid, citric acid, and glycerol: urea). Components were heated at 80 °C and stirred until a clear liquid was obtained. Distilled water was added (30 % v/v). A solid-liquid ratio of 1 g pomace per 10 ml of eutectic solvent was used.

Constitue une appellation d’origine “la dénomination géographique d’un pays, d’une région ou d’une localité servant à désigner un produit qui en est originaire, et dont la qualité ou les caractères sont dus exclusivement ou essentiellement au milieu géographique, comprenant les facteurs naturels et les facteurs humains …”

Climate change is leading to an increase in average temperature and in the frequency and severity of heatwaves that is already significantly affecting grapevine phenology and berry composition (Webb et al., 2010). This is compounded by water stress, which is well known to increase the vulnerability of grapevines and berries to heatwaves. In hot climate regions like australia, grape production is only possible due to relatively secure supplies of water for irrigation. However, the upper temperature limits for berry survival of well-watered grapevines remains to be tested.

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.