Hplc-ms analysis of carotenoids as potential precursors for 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) in riesling grapes

In Castilla-La Mancha as other winegrowing regions, vineyards suffer the effects of the global climate warming. Severe spring and summer droughts are increasingly frequent, which concur with the phenological stages most susceptible to water and temperature stress. Under these conditions, irrigation use is required in order to ensure the vineyard growing sustainability. However water resources are increasingly limited, for this reason is required to choose cultivars displaying high water use efficiency.

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?

Monferrato is a sub region of Piedmont featuring an endless series of hills which have been moulded through the centuries by laborious farming. Vineyards have always been the protagonists of Monferrato landscape. Asti vineyards have been well-known since Roman times and Pliny the Elder mentions them.

Grape composition is strongly influenced by climate conditions. Their expected modifications in near future, notably because of increased temperatures, could significantly modify the biochemical composition of berries at harvest, and thus wine typicity and quality. Elevated temperatures favor sugar accumulation in grapes, enhance malic acid degradation and modify the amino acid content. They also reduce significantly anthocyanin accumulation in Merlot, leading to the imbalance between anthocyanins and sugars, while no significant effects on final anthocyanin levels were reported in Tempranillo[1] and finally affect aromas or aroma precursors.

In vitro culture makes it possible to carry out specific studies that would not be possible with whole plants grown in the field or in a greenhouse. Cryopreservation allows long-term preservation without metabolic changes in the plant material and cryotherapy can be efficient in virus elimination, which is a major scientific challenge.
The preculture media of cryopreservation protocols were evaluated on three Croatian grape varieties with different antioxidants (salicylic acid, ascorbic acid and glutathione). The highest growth in vitro was achieved on the medium with the addition of glutathione and the lowest with the addition of salicylic acid.