ASSESSMENT OF GRAPE QUALITY THROUGH THE MONITORING OFPHENOLIC RIPENESS AND THE APPLICATION OF A NEW RAPID METHOD BASED ON RAMAN SPECTROSCOPY

Previous research on the fruity character of red wines highlighted the role of esters. Literature provides evidence that, besides these esters, other compounds that are not necessarily volatiles may have an important impact on the overall aroma of wine, contributing to a modulation of its global aromatic expression. The goal of this work was to assess the olfactory consequences of a mixture between esters and proanthocyanidic tannins, through sensory and physico-chemical approaches.
Sensory analysis of numerous aromatic reconstitutions, including triangular tests, detection thresholds, and sensory profiles, were conducted in order to evaluate the sensory impact of tannins on red wine esters perception.

The well-known antifungal and antibiotic molecule, eugenol, is widely spread in various plants including clove, basil and bay. It is also abundant in the hybrid grapevine cultivar (cv) Baco blanc (Vitis vi-nifera x Vitis riparia x Vitis labrusca), created by François Baco (19th century) in the Armagnac region. This study confirmed this cv as highly resistant to Botrytis cinerea by comparing fruit rot incidence and severity with two Vitis vinifera cultivars: Folle Blanche and Ugni Blanc. We have demonstrated the efficiency of eugenol in vitro, by further investigating the effect of small concentrations of eugenol, 3 to 4 ppm (corresponding to IC10), on B. cinerea. By comparing the two major modes of action (direct or volatile antibiosis), the vapour inhibiting effect of eugenol was more powerful. In the skin of Baco blanc berry, the total eugenol concentration reached a maximum at veraison, i.e. 1118 to 1478 μg/kg.

The sensory characteristics of wine are a topic studied by several researchers over time, but it continues to be a current and challenging subject. These characteristics are fundamental for the consumer acceptability, which has increasingly aroused their interest to modulate them in line with current market trends and innovation demands. The wine physical-chemical and sensory properties depend on a wide set of factors: they begin to be designed in the vineyard and are later constructed during the various stages of winemaking. Afterwards, the wine is placed in bottles and stored or commercialized.

Interest and willing-ness to buy alcohol-free wines by customers is increasing for several years [1]. Due to the rising relevance of dealcoholised wines it is the objective of this study to contribute to a better understanding of the flavor variation among dealcoholised wines and to explore enological measures, how to improve final quality.
First a range of commercial, alcoholfree white wines were analysed by the holistic sensory method projective mapping, including a question for hedonic acceptance. Based on the combination of a non-target-HS-SPME-GC/MS analysis with sensory analysis we obtained a clustering of the wines into three groups.

A critical aspect of wine quality is the overall expression of wine flavour, which is formed by the interplay of volatile aroma compounds, their precursors, and taste and matrix components.
Grapes directly contribute to wine only a small number of potent aroma compounds, and the unique
sensory attributes and perceived quality of a wine result from combining 100s of metabolites of grapes, yeast and bacteria, and oak wood.