Somatic embryogenesis and polyploidy in grapevine: morphological shoot and leaf traits variations

Lugana Protected Designation of Origin (PDO) wines are made from Turbiana grapes. The aroma of Lugana wines results from the combined contribution of esters, terpenes, norisprenoids, sulfur compounds and the benzenoid methyl salicylate. This study aims to investigate how volatile aroma compounds are affected by different nitrogen supplies and yeast strains. Wines were produced with a standard protocol with 2021 Turbiana grapes with two different yeasts Zymaflore Delta e Zymaflore X5 (Laffort, France).During the alcoholic fermentation of the must, when H2S appeared, additions of various nitrogen supply were made: inorganic nitrogen, organic nitrogen, a mix of inorganic and organic nitrogen and organic nitrogen with an addition of pure methionine. During wine fermentation, a daily measurement of hydrogen sulfide was carried out.

The chemistry of wine oxidation is captured in the reactions between the oxidation products, mostly reactive electrophiles, with other wine constituents. An understanding of both components and their reactions can lead to ideas and techniques to control and mitigate or enhance these reactions to allow for the desired development of the wine. Current investigations are yielding much useful information about oxidation reactions in wine.

The importance of the non-Saccharomyces yeasts (NSY) in winemaking has been extensively reviewed in the past for their aromatic or bioprotective capacity while, recently their antioxidant/antiradical potential has emerged under winemaking conditions. In the literature the antioxidant potential of NSY was solely explored through their capacity to improve glutathione (GSH) content during alcoholic fermen- tation [1], while more and more studies pointed out the activity of the non-glutathione soluble fraction released by yeasts [2].

Samples from 3 wine types were treated with a cationic exchange resin (7 lots) and stored for 8 years (47 samples). Forty-seven parameters were determined, including (1) important substrates with impact in white wine oxidation and (2) markers of oxidation. From group 1, sugars, elements, phenolic compounds, α-dicarbonyls and SO2 and from group 2, browning (A420), acetaldehyde, alkanals, furanic compounds were quantified.

Chitosan is an effective antimicrobial agent available in the wine industry, because it ensures the control of a of spoilage microorganisms, such as Brettanomyces of lactic acid bacteria.