Impact of yeast derivatives to increase the phenolic maturity and aroma intensity of wine

AIM Methyl salicylate (MeSA) has been reported as a potentially impactful compound in Verdicchio wines produced in central Italy. Lugana is another white wine produced in the north-east of Italy from a grape locally known as Trebbiano di Soave, sharing a very similar genetic background with Verdicchio. The aims of this study were evaluating MeSA occurrence in Lugana, assessing its aroma impact on white wines aroma and elucidating its biogenesis during vinification. METHODS Fifteen Lugana wines were analysed for methyl salycilate content in comparison with Verdicchio, Pinot grigio and Garganega wines. MeSA impact on white wine aroma was studied by means of triangular test, adding MeSA at different concentrations. Possible routes of MeSA formation by yeast were investigated by means of a high throughput assay in which S. cerevisiae cells were put in contact with precursor such as salicylic acid (esterification) or glycosidic extracts (glycosidase). Sub-fractions of Lugana glycosidic extracts were also obtained by HPLC fractionation, allowing further evaluation of precursors role.

New breeding techniques (NBTS) could play a significant role in the genetic improvement of grapevine by producing new grape varieties with improved quantitative and qualitative characteristics. However, the application of these new techniques faces some technical challenges. One of the challenges is the generation of embryogenic calluses, which are not only difficult to obtain but it is also difficult to maintain their competence during in vitro cultivation, and thus regenerate plants without defects.

The chemistry of wine is notably complex and is modified by ageing of the bottles. The composition of wines is the result of vine production (under the influence of vintage, climate and soils); yeast production (under the influence of juice composition and fermentation management); lactic bacteria production (under the influence of young wine composition and malolactic fermentation management); and of the ageing process either in vats, barrels or bottles or both. The composition is linked to the quality perceived by consumers but also to their origin, sometimes associated to the “terroir” concept.

The use of compost as amendment in agriculture is a well-established practice, strongly recommended for numerous benefits.

The phenolic compounds (cathechins, cynnamic acids, anthocyanidins) in wines made from 6 vine-varieties (Sangiovese, Cabernet S., Nero d’Avola, Foglia Tonda, Pinot N., Mazzese) grown in 4 different pedoclimatic zones of Tuscany (Arezzo, Grosseto, Pisa and Lucca) have been analyzed by HPLC.