Changing New Zealand climate equals a changing New Zealand terroir?

Une étude préliminaire des situations météorologiques journalières a été réalisée pour l’Afrique du Sud et pour les mois de février (période de maturation des raisins dans la Province occidentale du Cap), à l’image de la classification synoptique réalisée aux latitudes tempérées en France (Jones & Davis, 2000), afin d’étudier les relations entre le climat et la viticulture à des latitudes plus basses.

Valpolicella is a famous Italian wine-producing region. Wines produced in its different sub-regions are believed to be aromatically different, as confirmed by recent studies in our laboratory. Aging is a very common practice in Valpolicella and it is required by the appellation regulation for periods up to four years require wines. The aim of this study was to investigate the evolution, during aging, of volatile chemical composition of Valpolicella wines obtained from grapes harvested in different sub-regions during different vintages.

Oxygen management is crucial in terms of wine quality. Even more for white and rosé wines, which are less protected against oxidation than reds due to the lower levels of antioxidant polyphenols. This need is due to the existence of equilibria between chemical forms depending on the redox potential.

The enzymatic browning of grape must is still a major problem in oenology today [1] being particularly serious when the grapes have been infected by grey rot [2]. Browning is an oxidation process that causes certain foods to turn brown, which often leads to them being rejected by consumers [3]. This is a particular problem in the case of wine, because grape must is very vulnerable to enzymatic browning [4].

Vines are exposed to environmental conditions that cause abiotic stress on the plants (drought, nutrient and mineral deficits, salinity, etc.). Polyamines are growth regulators involved in various physiological processes, as in abiotic plant stress responses. Stressful conditions can modify grape’s composition, and in this work, we have focused on studying the effect of abiotic stress on the composition of polyamines and amino acids in grapes. In addition, the effect of grape variety on these compounds has been studied.