Characterization of bunch compactness and identification of associated genes in a diverse collection of cultivars of Vitis vinifera L.

The effects of climate change produce an increase in sugar concentration and a decrease in acidity, without reaching the optimum grape phenolic maturity [1]. The aim of this work was to characterize 25 white grape varieties

The production of grated vines is a complex process from grafting to final sorting in nurseries. To reach the market, grafted grapevines must meet three criteria by law in France: resistance to a manual graft union test (named thumb test), a minimum number of three roots and a woody shoot of at least 2 cm long.

Quantity and quality of flavonoïds in grape berries are important parts of their global quality. Several studies had shown that tannins are responsible for some major flavour properties of red wines such as colour, bitterness and astringency. Nevertheless, their synthesis and properties are still misunderstood. Some studies had suggested that the tannic pool was set before veraison. Thus, the comprehension of the relations between environment and setting of this tannic pool, up to the harvest, is not sufficient.

There is an increasing interest by the wine industry to know the performance of new winegrape cultivars in traditional areas to find out which cultivars could better complement the traditional wines. In warm areas, isohydric cultivars and high yields are sought in order to save water and to delay maturity.

Mint aromas in wine, which manifest as “cool” or “fresh” character, can originate from different chemical classes, one of which is the terpenoids. A broadly diverse, naturally occurring class of chemical compounds, terpenes possess wide applications across multiple industries due to their pharmaceutical, antiseptic, medical, and aromatic properties. Monoterpenes, a subclass of terpenoids, likewise play a major role in wine sensory perception. Within the monoterpenes, those possessing “mint” odor qualities have often been studied in the context of “vegetal” or “herbal” wine faults; however, their role in positive aromatic evolution is less understood. Yet an extensive 2015 study of older premium Bordeaux red wines identified mint as a contributing factor in quality bouquet development. From that point, it was necessary to investigate the origins of those monoterpenes as well as the chemical conditions required for their development during ageing. Those two key points could finally facilitate predicting the apparition of minty character in older wines based on their composition while young.
A principal contributor is the cyclic monoterpene limonene, which was isolated relatively early in grapes and wine. Not only does limonene itself possess a cool, fresh odor, it is also a precursor for, and possible derivative of, additional mint monoterpenes. Among the most commonly found monoterpenes, limonene and its derivatives can constitute the majority of the essential oils of citrus fruits, mint and herb plants, and coniferous trees. Many of these mint monoterpenes also occur in grapes and wine. With aromas ranging from woody and earthy to citrus to mint and herbaceous, their contribution to wine is potentially diverse and multi-faceted. While sometimes, found at concentrations below the sensory threshold, synergistic effects between these molecules could render them perceivable.
This review looks at limonene and its transformation as studied in different matrices, and potential parallels or analogues in wine. Moreover, within the complex kinetics of wine aging, the relative concentrations of mint monoterpenes appears to continue to evolve and change, with additional evidence from model wine solutions suggesting they may even revert to their originating precursors. Continued study of mint monoterpenes and their role in wine aromatics will contribute to a deeper understanding of the development of aging bouquet and the longevity of premium wines.