New understanding on sulfites reactivity in wine

The interactions among aromatic compounds and proteins is an important issue for the quality of foods and beverages. In wine, the loss of flavor after vinification is associated to bentonite treatment and this effect can be the result of the removal of aroma compounds which are bound wine proteins. This phenomenon was recently demonstrated for long chain fatty acids and their ethyl esters (1). Since these latter compounds are spectroscopically silent, their association with proteins is not easy to measure.

Although vitamins stand as major actors to yeasts prime metabolic pathways, their significance in oenology and winemaking remains rather obscure nowadays, having been mostly unexplored for several decades.

Concepts such as typicality are difficult to demonstrate using the limited set of samples that can be subjected to sensory evaluation. This is due both to the complexity of the concept and to the limitations of traditional sensory evaluation (number of samples per session, panel fatigue, the need for multiple sessions and methods, etc.). On the other hand, there is a large amount of data already available, accumulated through many years of consistent evaluation. These data are held in repositories (such as Platter’s Wine Guide in the case of South Africa Wine, wineonaplatter.com) and in technical notes provided by the producers.

Grapevine downy mildew (GDM), caused by the oomycete Plasmopara viticola, is one of the most destructive diseases of Vitis vinifera worldwide. All V. vinifera cultivars are susceptible to P. viticola infection, and epidemics can spread across an entire vineyard within a matter of weeks. Severe outbreaks cause substantial reductions in yield and fruit quality. Tracking GDM spread by manual scouting is time-consuming and unfeasible over large spatial extents.

Work aimed at understanding the relationship between a terroir, in the agronomic sense, and the physico-chemical characteristics of grapes or wine are numerous today, as evidenced by the program of this symposium. But for an economist, the central question remains to know how the terroir can intervene in the construction of the economic value of wine and in the differentiation of its prices. Is the terroir effect recognized by the end consumer or is it only an internal adjustment variable in the production systems? Through which indicators can this terroir effect be managed by the various operators in the sector? In the end, isn’t it better to invoke a “territorial effect” that the actors can build, and of which the terroir would be one of the possible components?