Guyot or pergola for dehydration of Rondinella grape

‘Mavrodafni’ (Vitis vinifera L.) is considered one of the oldest grapevine cultivars indigenous to the Greek vineyard, with western Peloponnese being its primary center of cultivation. ‘Renio’ is considered to be either a variant of ‘Mavrodafni’ or an altogether different cultivar. Both ‘Mavrodafni’ and ‘Renio’ can be found in the vineyards of the centers of cultivation, since ‘Renio’ is considered to be more productive compared to ‘Mavrodafni’, and for this reason, it has gradually replaced ‘Mavrodafni’ from cultivation over the course of time. The aim of the present study was to assay the mechanical properties, the polyphenolic content and the antioxidant capacity of skin extracts and must of berries coming from ‘Mavrodafni’ and ‘Renio’, cultivated in the same vineyard as well as in the different regions of cultivation of the PDO Mavrodafni Patras.

During bottle aging, the development of wine aroma through low and gradual oxygen exposure is often positive in red wines, but can be unfavorable in many cases, resulting in a rapid loss of fresh, fruity flavors. Prematurely aged wines are marked by intense prune and fig aromatic nuances that dominate the desirable bouquet achieved through aging (Pons et al., 2013). This aromatic defect, in part, is caused by the presence of 3-methyl-2,4-nonanedione (MND). MND content was shown to be lower in nonoxidized red wines and higher in oxidized red wines, which systematically exceeds the odor detection threshold (62 ng/L).

The fresh mushroom off-flavour (FMOff) has been appearing in wines since the 2000s. Some C8 compounds such as 1-octen-3-one, 1-octen-3-ol, 1-hydroxyoctan-3-one, 3-octanol and others are involved in this specific off-flavour [1-3]. At the same time, glycosidic precursors of some FMOff compounds have been identified in musts contaminated by Crustomyces subabruptus [4], highlighting the role of aroma precursors in this specific taint. However, the fate of these volatile molecules and glycosidic fractions during fermentation is not well known.

Flavescence dorée (FD) stands out as a significant grapevine disease with severe implications for vineyards. The American grapevine leafhopper (Scaphoideus titanus) serves as the primary vector, transmitting the pathogen that causes yield losses and elevated costs linked to uprooting and replanting. Another potential vector of FD is the mosaic leafhopper, Orientus ishidae, commonly found in agroecosystems. The current monitoring approach involves periodic human identification of chromotropic traps, a labor-intensive and time-consuming process.

Astringency is a crucial sensory attribute typically described as the drying and/or puckering sensation occurring after the consumption of tannin-rich foods and beverages. In this study, thirty-seven red wines from different varieties, origins and styles were evaluated, analyzing both chemical and sensory features. Principal Component Analysis was used for dimensionality-reduction and for correlating selected chemical parameters against astringency. The results showed that tannin content was the most important chemical parameter influencing overall astringency but more clearly the dryness sub-quality, followed by pH, titratable acidity and alcohol content.