Grape VOCs response to postharvest short-term ozone treatments

Ozone has been recently recognized as an efficient sanitizing agent in wine industry because of its powerful oxidizing properties. Furthermore, postharvest treatments of grapes with ozone can stimulate defense responses by synthetizing secondary metabolites against oxidative stress. In this study, the effect of postharvest short-term ozone treatments was assessed for the first time on free and glycosylated volatile organic compounds (VOCs) of winegrapes. Two different ozone concentrations (30 and 60 μL/L) and exposure times (24 and 48 h) were investigated just after treatment (fresh grapes) and after partial dehydration up to 20% weight loss (withered grapes). The study was carried out on Moscato bianco winegrapes (Vitis vinifera L.) due to the importance of terpenes in white aromatic cultivars to produce high quality wines. The results obtained showed that short-term ozone treatment caused a significant decrease in total contents of free VOCs in fresh grapes, mainly due to terpenes. Among them, linalool, geraniol, and nerol are the major aromatic markers of Moscato bianco grapes. Ozone entailed a significant decrease of free linalool contents in fresh grapes, the less stressful ozone treatment showing the smaller linalool degradation. However, the stronger and longer ozone treatment induced the synthesis of this compound probably in response to higher abiotic stress. Instead, significant changes were not observed in geraniol and nerol contents in fresh grapes. This last ozone treatment also reduced the loss of free linalool by water loss in withered grapes even though total VOCs and terpenes remained relatively stable. Furthermore, ozone seems to promote the synthesis of free (+)-4-carene and 4-terpineol in withered grapes under certain treatment conditions. Regarding glycosylated compounds, total VOCs and terpenes were less sensitive to ozone. Our findings highlight that ozone can be used as sanitizing agent in aromatic grape varieties prior to winemaking without affecting sharply the aromatic profile of fresh grapes and even improving it in withered grapes

Evolution of the Phenolic Content and Extractability Indices During Ripening of Nebbiolo Grapes from the Piedmont Growing Areas over Six Consecutive Years

The phenolic composition and extractability indices of grape berries play a key role in assessing redwine quality because the relationship between grape phenolic maturity and wine phenolic compositionis well known. In this work, grape quality indices were determined in Nebbiolo grapes from two growingareas of Langhe (South Piedmont), at different stages throughout the ripening process in six consecutiveyears (2004 to 2009), with the aim of evaluating the ripening- and growing area-related changes in thegrape indices separately. The effect of vintage was also investigated. Ripeness data were compared withanalogous data determined in Nebbiolo grapes grown in the Carema area (North Piedmont). The vintageeffect far outweighed any changes in the grape indices introduced by the ripening stage, even those arisingfrom differences in the production area. In the Langhe and Carema zones, the average berry mass, pH,total acidity, total anthocyanins extractable at pH 3.2, total flavonoids and non-anthocyanin flavonoidsextractable at pH 1, and the seed maturity index were seasonally dependent. The more ripening-affectedparameters were the technological ones. This work highlights the importance of determining the phenolextractability, since it provides relevant information that allows improved management of the macerationstage

Corrigendum

Twenty microsatellites (SSRs) reveal two main origins ofvariability in grapevine cultivars from Northwestern SpainVitis 49 (2), 55-62 (2010

Twenty microsatellites (SSRs) reveal two main origins of variability in grapevine cultivars from Northwestern Spain

The grapevine germplasm bank in the “Estación de Viticultura y Enología de Galicia, Xunta de Galicia”, holds fifteen grapevine cultivars with a total of 98 accessions: ‘Brancellao’, ‘Albarello’, ‘Caíño Astureses’, ‘Caíño Bravo’, ‘Caíño Blanco’, ‘Caíño Gordo’, ‘Albarín Negro’, ‘Caíño Longo’, ‘Caíño Redondo’, ‘Castañal’, ‘Mencía’, ‘Merenzao’, ‘Mouratón’, ‘Sousón’, and ‘Verdello’. Cultivars ‘Syrah’ and ‘Pinot Noir’ were included as references. Two different lineages were detected, one originating in ‘Caíño Astureses’ and the other in ‘Merenzao’, synonymy of the French cultivar ‘Trousseau’. Cultivars from Northwestern Spain derived from both of these cultivars by hybridization and selected genotypes that had adapted to local climatic conditions and became fixed by cuttings, explaining the domestication process of these grapevine cultivars. Both lineages differed in allelic frequencies and were distributed differently in Northwestern Spain, the first lineage in the west and the second, related with the French cultivar ‘Trousseau’, in the east. ‘Caíño Astureses’ was the most frequent genotype related by hybridization, indicating the importance that this cultivar had in the origin of grapevines in Galicia. In addition a total of 13 different genotypes were identified. The identity of ‘Brancellao’ and ‘Albarello’ was confirmed by SSR-markers. Other two synonyms were ‘Caíño Astureses’ and ‘Caíño Bravo’, and ‘Caíño Gordo’ and ‘Albarín Negro’. ‘Caíño Redondo’ showed two different genotypes, one related to ‘Caíño Astureses’ and the other to ‘Merenzao’. Two cultivars included in the collection from EVEGA were not reported previously, ‘Verdello’ and ‘Caíño Longo’.

Corrigendum

Twenty microsatellites (SSRs) reveal two main origins ofvariability in grapevine cultivars from Northwestern SpainVitis 49 (2), 55-62 (2010

A major QTL is associated with berry grape texture characteristics

Berry texture and berry skin mechanical properties are traits with high agronomic relevance because they are related to quality parameters and marketing requirements of wine, table, and raisin grapes. Searching for QTLs linked to berry texture, an F1 population of 152 individuals and their parents were used in this study. These F1 plants were obtained crossing Raboso Veronese, a seeded black wine grape cultivar, and Sultanina, a seedless white grape variety, especially used for raisins. Density flotation was applied for berry sorting improving the management of many and highly variable genotypes, irrespective of the quantification of specific molecule classes. Berries were evaluated for technological ripeness parameters and mechanical properties. Texture parameters were taken as raw data and as data normalised on berry dimensions, i.e., berry diameter or surface or volume. SSR molecular markers were used to produce a genetic map and a major QTL for berry texture was found on chromosome 18 with traits related to berry firmness showing a phenotypical explained variance higher than 60 %, and traits related to berry resilience, springiness and cohesiveness showing a variance higher than 50 %. Surprisingly, this QTL showed to be associated with SSR markers linked to VviAGL11, the main gene linked to seedlessness. VviAGL11 expression and co-expression profiling during grape ripening was evaluated using available information; this data suggested a role for this gene on the texture of a ripe berry