Instrumental Texture Analysis Parameters as Markers of Table-Grape and Winegrape Quality: A Review

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Etude du polymorphisme génétique de la vigne cultivée (vitis vinifera L.) à l'aide de marqueurs microsatellites (application à la caractérisation des cépages dans les vins)

MONTPELLIER-BU Pharmacie (341722105) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Cryo-laser scanning confocal microscopy of diffusible plant compounds

Background The in vivo observation of diffusible components, such as ions and small phenolic compounds, remains a challenge in turgid plant organs. The analytical techniques used to localize such components in water-rich tissue with a large field of view are lacking. It remains an issue to limit compound diffusion during sample preparation and observation processes. Results An experimental setup involving the infusion staining of plant tissue and the cryo-fixation and cryo-sectioning of tissue samples followed by fluorescence cryo-observation by laser scanning confocal microscopy (LSCM) was developed. This setup was successfully applied to investigate the structure of the apple fruit cortex and table grape berry and was shown to be relevant for localizing calcium, potassium and flavonoid compounds. Conclusion The cryo-approach was well adapted and opens new opportunities for imaging other diffusible components in hydrated tissues

Cryo-laser scanning confocal microscopy of diffusible plant compounds

Abstract Background The in vivo observation of diffusible components, such as ions and small phenolic compounds, remains a challenge in turgid plant organs. The analytical techniques used to localize such components in water-rich tissue with a large field of view are lacking. It remains an issue to limit compound diffusion during sample preparation and observation processes. Results An experimental setup involving the infusion staining of plant tissue and the cryo-fixation and cryo-sectioning of tissue samples followed by fluorescence cryo-observation by laser scanning confocal microscopy (LSCM) was developed. This setup was successfully applied to investigate the structure of the apple fruit cortex and table grape berry and was shown to be relevant for localizing calcium, potassium and flavonoid compounds. Conclusion The cryo-approach was well adapted and opens new opportunities for imaging other diffusible components in hydrated tissues

Typicité sensorielle de vins de l'AOC Coteaux du Layon et acceptabilité par les acteurs (professionnels et consommateurs) de vins avec des titres d'alcool volumique plus faibles

In order to maintain an optimum sugar / acid balance in a changing context, winegrowers of the Coteaux du Layon PDO, a sweet wine of the middle Loire valley, wish to know if a final alcohol content (TAV) lower than the minimum imposed by the regulation of the PDO (11% vol. today) would affect the typicality of the wines. To answer this question, a study was carried out in 4 steps. 1) To know the expected typicality of these wines, focus groups were conducted with 26 professionals. 2) In order to assess the acceptability of lower TAV wines, based on a sample of 24 wines (commercial wines and experimental wines with TAV between 8% vol. and 10% vol.), 31 professionals scored levels of exemplarity. 3) A trained panel made a fine sensory description. 4) Finally, a selection of 8 wines from these 24 were evaluated by 163 consumers, they scored levels of preference. The results of steps 1) and 2) show a strong consensus among professionals to assess the exemplarity of wines. Experimental wines obtained exemplary scores above the average of the scale and can therefore be considered as good examples. In step 3), the trained panel generated the sensory attributes to describe the wines: 21 descriptors of odors and aromas and 6 of flavors, which reveal the sensory complexity of the wines. In stage 4), in general, the 8 wines evaluated by the consumers were all appreciated. The results suggest that a sufficiently high amount of residual sugar content would enhance the acceptability of lower TAV wines by both professionals and consumers. The winegrowers of the syndicate of Coteaux du Layon PDO thus have factual elements to update the specification of the PDO (decreasing the minimum TAV threshold), in interaction with INAO (the French national institute of origin and quality)

Cryo-microscopie confocale pour la localisation des ions pariétaux dans les tissus fruits charnus

Cryo-microscopie confocale pour la localisation des ions pariétaux dans les tissus fruits charnus. 11èmes Journées du Réseau Français des Paroi

Analyses multivariées pour une meilleure compréhension des pratiques viticoles et des facteurs du milieu afin d'expliquer la qualité du raisin

Les viticulteurs disposent de plusieurs moyens de mesure de la qualité de leurs raisins lorsqu'ils sont arrivés à maturité pour la vendange. La prédiction de la qualité du raisin, vise à formaliser le savoir-faire des experts (viticulteurs et conseillers) pour développer un modèle mathématique qui définira les relations entre la qualité du raisin et les facteurs (pratiques, sol, climat) ayant permis d'aboutir à cette qualité. La présente étude a pour objet de développer une première étude exploratoire permettant d'investiguer chaque paramètre de données et chaque facteur précédent la construction effective d'un modèle explicatif, voire prédictif de la qualité du raisin obtenu à la vendange à partir de pratiques culturales et des données du milieu. Le jeu de données utilisé pour construire le modèle provient de parcelles produisant du raisin en AOP (Appellation d'Origine Protégée) à partir du cépage Chenin situé en moyenne Vallée de la Loire (France), destiné à produire un vin blanc sec pendant lors des millésimes 2010 à 2013. Les pratiques, le milieu et la qualité du raisin ont été analysés pour chacune de ces parcelles et constituent la base de données du modèle. Ce dernier s'appuiera par la suite sur une analyse statistique nommée Régression PLS (Partial Least Square)

Modeling grape quality by multivariate analysis of viticulture practices, soil and climate

International audienceAims: The present study aims to model grape quality criteria by combining a large number of viticultural practices and soil and climatic variables related to the main determinants.Methods and results: A database has been developed using the Chenin blanc grape variety in a protected designation of origin. A statistical model, namely, a partial least squares (PLS) regression, was performed for each grape quality criterion (sugar content, total acidity, malic acid, tartaric acid, yeast available nitrogen, pH and bunch rot). This statistical analysis identified the main viticultural practices as well as soil and climate variables related to the grape quality at harvest. The results highlight the relationships between the vine pruning length (spur pruning = short pruning or cane pruning = long pruning) and pH and malic acid but also reveal even more significant relationships with tartaric acid, yeast available nitrogen and bunch rot. The dryness index and the plant density have a strong influence on the grape malic acid concentration and pH, respectively. Vine perennial practices are the greatest contributors to the grape the yeast available nitrogen concentration.Conclusion: The models note the most relevant viticultural practices and soil and climatic variables driving each studied grape quality criterion.Significance and impact of the study: The results provide a better understanding of the major variables influencing grape quality

Phenolic distribution in apple epidermal and outer cortex tissue by multispectral deep-UV autofluorescence cryo-imaging

Phenolic compounds in fruit are involved in responses to biotic and abiotic stresses and are responsible for organoleptic properties. To establish the distribution of these secondary metabolites at the tissue and sub-cellular scales, mapping of fluorescence in apple epidermis and outer cortex tissue in cryogenic condition was performed after deep-UV excitation at 275 nm. Douce Moen and Guillevic cider apple varieties were sampled and frozen after harvest, after 30 days at 4 degrees C and after 20 days at room temperature. Image analysis of fluorescence emission images acquired between 300 and 650 nm allowed the assignment of fluorescence signals to phenolic compound families based on reference molecules. Emission attributed to monomeric and/or condensed flavanol was localized in whole tissue with major fluorescence in the cuticle region. Hydroxycinnamic acids were found predominantly in the outer cortex and appeared in the cell wall. Fluorescent pigments were mostly found in the epidermis. The distribution of flavanols in the sub-cuticle and phenolic acids in the outer cortex distinguished apple varieties. Storage conditions had no impact on phenolic distribution. The proposed fluorescent imaging and analysis approach enables studies on phenolic distribution in relation to fruit development, biotic/abiotic stress resistance and quality