Podcasts – Terroir Congress 2020

The composition of grape berry cell walls was studied on two grape varieties, two years and two maturation levels at the same time as the extraction of anthocyanins and tannins. The chemical composition of skins, seeds, and pulps, focused on polyphenols and polysaccharides, was compared to the chemical composition in polyphenols after extraction from the skins in model solutions or after wine making of the berries. Polyphenols were mainly characterized by UPLC-MS and HPLC-SEC. Polysaccharides were characterized by analysis of the neutral sugar compositions, and also by the CoMPP (comprehensive micropolymer profiling) analysis, a new method which targets the functional groups of cell wall polysaccharides.

Tomatoes and Grapes are berries that are genetically related and therefore at least partially their developmental pathways leading to a fleshy fruit should share some of the components. In a sense knowledge obtained from the model plant tomato could be useful for grape and conversely the more amenable tomato can be used to test some hypothesis that would be difficult to obtain in grape. Research in my lab and other labs have led to a better understanding of the molecular genetics mechanisms underlying fruit development and ripening in tomato and more specifically those related to metabolite accumulation that may lead to changes in fruit nutritional and flavor composition. This research has involved the use of genetic variability in natural population, but also biparental population and genetically engineered lines that are easy to develop in tomato tomato but not in grape. NGTs also can be easily implemented in tomato to not only speed up the gene-to-trait but also develop new tomato varieties.

Temperature fluctuations can significantly affect the chemical composition of wine and in turn its taste and aromas.

Probably one of the most counterintuitive impacts of climate change on vine is the increased frequency of late frost. Champagne, due to its septentrional position is historically and regularly affected by this meteorological hazard. Champagne has therefore developed a strong experience in frost protection with first experiments dating from the end of 19th century. Frost protection can be divided in two parts: passive and active. Passive protection includes all the methods that do not seek to modify the vine’s environment or resistance at the time of frost. The most iconic passive protection in Champagne is the establishment of the individual reserve. This reserve allows to stock a certain quantity of clear wine during a surplus year to compensate a meteorological hazard like frost during the following years. Other common passive methods are the control of planting area (walls, bushes, topography), the choice of grape variety, late pruning, or the impact of grass cover and tillage. Active frost protection is also divided in two parts. Most of the existing techniques tend to modify vine’s environment. Most of the time they provide warmth (candles, heaters, windmills, heating cables…), or stabilise bud’s temperature above a lethal threshold (water sprinkling). The other way to actively fight is to enhance the resistance of buds to frost (elicitors). The Comité Champagne evaluates frost protection methods following three main axes: the efficiency, the profitability, and the environmental impact through a lifecycle assessment. This study will present the results on both passive and active protection following these three axes.

Cette communication sera basée sur les résultats d’une étude auprès des consommateurs réalisée par la société G3 pour l’I.N.A.O. sur les attitudes des consommateurs vis à vis des produits de terroir et des A.O.C. et sur un mémoire de DEA soutenu par Monsieur J-C. DURIEUX à l’Université de Paris X Nanterre, consacré aux variables explicatives du comportement d’achat des vins A.O.C.