Effect of nitrogen content on fermentation kinetics and aroma profile of assyrtiko wine

AIM:Valpolicella is a wine region located in Italy north-east, famous for the production of dry and sweet red wines from withered grapes, including Amarone and Recioto. The aim of this study is to understand the influence of the withering process on Corvina and Corvinone wines aroma profiles. METHODS:Wines were produced with a standard red wine winemaking protocol with Corvina and Corvinone grapes from different Valpolicella vineyards and vintages. In consideration of the local traditional practice of post-harvest withering of the grapes, wines from each vineyard were obtained from either fresh and withered grapes. Wines were analysed by Solid Phase Extraction and Solid Phase Micro Extraction gas chromatography coupled to mass spectrometry.

Bottle ageing is a critical period for wine quality, as it undergoes various chemical and sensory changes during storage. Ideally, a phase of qualitative ageing, during which wine sensory quality improves, is followed by a decline of quality. Understanding how different oenological variables influence these phases is a key challenge in modern winemaking. Recent studies highlighted the significant role of oxygen in modulating reactions involving volatile and non-volatile components, impacting aroma evolution during bottle aging. Oxygen exposure of wine during bottle ageing is mediated by closure.

The use of multivariate statistics to correlate chemical data to spectral information seems as a valid alternative for the quantification of red wine phenolics. The advantages of these techniques include simplicity and cost effectiveness together with the limited time of analysis required. Although many
publications on this subject are nowadays available in the literature most of them only reported feasibility
studies. In this study 400 samples from thirteen fermentations including five different cultivars plus 150
wine samples from a varying number of vintages were submitted to spectrophotometric and chromatographic phenolic analysis.

In a context of reducing herbicide use, the most part of French vineyards are developing permanent grass cover crops on inter-rows alleys, while under the row chemical weeding remains the general case. The setting up of a controlled grass cover crop under the vine row could be a complementary alternative to mechanical weeding – which one is very restrictive – interesting from a technical and economical point of view. The present study aimed at assessing agronomic impacts of grass cover crop under the row in different climatic conditions and production objectives.

Commercial grape production relies on training grapevine cultivars onto a variety of trellis systems. Training allows for well-lit leaves and clusters, maximizing fruit quality in addition to facilitating cultivation, harvesting, and diseases control. Although grapevines can be trained onto an infinite variety of trellis systems, most red and white cultivars are trained to the standard VSP (Vertical Shoot Positioning) system. However, red and white cultivars respond differently to VSP in fruit composition and growth characteristics, which are yet to be fully understood. Therefore, the objective of this study was to examine the influence of the VSP trellis system on fruit composition of three red, Cabernet Sauvignon, Merlot and Syrah, and three white, Chardonnay, Riesling, and Gewurztraminer cultivars grown under uniform growing conditions in the same vineyard. All cultivars were monitored for maturity and harvested at their physiologically maximum possible sugar concentration to compare various fruit quality attributes such as Brix, pH, TA, malic and tartaric acids, glucose and fructose, potassium, YAN, and phenolic compounds including total anthocyanins, anthocyanin profile, and tannins. A distinct pattern in fruit composition was observed in each cultivar. In regards to growth characteristics, Syrah grew vigorously with the highest cluster weight. Although all cultivars developed pyriform seeds, the seed size and weight varied among all cultivars. Also varied were mesocarp cell viability, brush morphology, and cane structure. This knowledge of the canopy architectural characteristics assessed by the widely employed fruit compositional attributes and growth characteristics will aid the growers in better management of the vines in varied situations.