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In the present study, viticultural and oenological parameters of six clones of Muscat a Petits Grains Blancs (MPG) and five clones of Muscat giallo were investigated. Differences were found between varieties and clones in the occurrence of the phenological phases: bud break, véraison, and maturity. In the MPG clones (B41-5, FR 94, MPG 154, MPG 454, and MPG 455), all three phenological phases started earlier, resulting in earlier grape maturity and higher total soluble solids content (TSS) in grapes at harvest compared to the M. giallo clones (R1, VCR100, VCR 102, and VCR 5, BEMK 33). The MPG clones also resulted in higher cluster weight, higher yield per vine, and lower must pH compared to the M. giallo clones. The only exception was the MPG clone R2, which showed more similarities with the M. giallo clones. The wines of the MPG clones showed a tendency toward higher values for alcohol, citronellol, total acids, and total dry matter. In contrast, the wines of the M. giallo clones and the R2 clone of MPG showed higher pH and higher levels of linalool, α-terpineol, geraniol, and nerol. Although R2 is classified as a clone of MPG, our results indicate a strong similarity with the M. giallo clones studied. This study has highlighted the differences in phenological development and grape and wine quality characteristics between MPG and M. giallo clones. Therefore, clone selection can be an important tool for winemakers to develop the desired wine style and adapt to climatic changes., V raziskavi smo preučili vinogradniške in enološke parametre šestih klonov sorte Muscat a Petits Grains Blancs (MPG) in petih klonov sorte Muscat giallo. Med sortami in kloni so bile ugotovljene naslednje razlike v fenoloških fazah: odganjanje zimskih očes, dozorevanje in zrelost grozdja. Začetek vseh treh fenoloških faz je bil zgodnejši pri klonih sorte MPG (B 41-5, FR 94, MPG 154, MPG 454 in MPG 455), kar se je odrazilo v zgodnejšem dozorevanju grozdja in večji vsebnosti skupne suhe snovi (TSS) v moštu ob trgatvi, v primerjavi s kloni sorte M. giallo (R1, VCR100, VCR 102 in VCR 5, BEMK 33). Kloni sorte MPG so imeli v primerjavi s kloni sorte M. giallo večjo maso grozda, večji pridelek po trsu in nižjo vrednost pH mošta. Edina izjema je bil klon R2 sorte MPG, ki je bil po vinogradniških parametrih bolj podoben skupini klonov sorte M. giallo. V vinih, pridelanih iz grozdja klonov sorte MPG, smo izmerili večje vsebnosti alkohola, citronelola, skupnih kislin in ekstrakta brez sladkorja. V nasprotju pa so imela vina, pridelana iz klonov sorte M. giallo in klona R2 (sorte MPG), izmerjeno višjo vrednost pH in večje vsebnosti linaloola, α-terpineola, geraniola in nerola. Čeprav je bil klon R2 klasificiran kot klon sorte MPG, naši rezultati kažejo veliko podobnost tega klona s kloni sorte M. giallo. Študija je poudarila razlike v fenološkem razvoju in kakovostnih parametrih grozdja in vina med kloni sort MPG in M. giallo. S selekcijo klonov lahko pomembno vplivamo na kakovostne parametre grozdja, kar neposredno vpliva na slog vina. Hkrati lahko s pravilno odbiro klonov vinogradniško prakso prilagajmo spreminjajočim se podnebnim razmeram in ohranjamo tipičnost pridelanih vin.

International audience; Late ripening berry dehydration is an important phenomenon that occurs through grape berry water loss due to the alteration of the fruit water budget when transpiration and potential water back flow to the plant exceed the import of water into the berry through the phloem and xylem. Berry shrivelling can have a significant economic impact, reducing yields by ≥25 % with consequences on berry composition and the resulting wine. Its occurrence and consequences are expected to increase due to predicted climate change, shifting grape development and ripening into warmer periods (i.e., heat waves and drought events).; La déshydratation des baies en fin de maturation est un phénomène majeur causé par la perte d’eau des baies par suite d’une altération de leur balance hydrique. Cette altération apparaît quand les flux liés à la transpiration et au reflux potentiel d’eau vers la plante excèdent ceux de l’entrée d’eau dans la baie via le phloème et le xylème. Le flétrissement des baies peut avoir un impact économique significatif, avec une réduction des rendements ≥25 %, et des conséquences sur la composition des baies et sur le vin qui en résulte. L’apparition de ce phénomène et ses conséquences seraient amenées à s’intensifier à cause du changement climatique prévu, lequel causerait un décalage des stades de développement et de maturation des baies vers des périodes plus chaudes (c’est-à-dire des canicules et des épisodes de sécheresse).

Comprehensive two-dimensional gas chromatography (GCxGC) has emerged as a powerful analytical technique for unraveling the volatile composition of complex matrices. This work will present three applications of GCxGC Tof-MS in the fields of wine and olive oil, aimed to identify biomarkers which could be used in the quality control. In the first study this analytical technique was used to monitor, during shelf life in realistic condition, the headspace profile of aromatic compounds in white wines, through an analysis of untargeted metabolomics. The aim of this study was to assess the impact of the exposure to the light on large number of white wines bottled in bottles of different colors on their aromatic profiles. In the second study an investigation of Shiraz wine volatile composition from four vineyards located in the Riverina region of Australia was performed by accessing wines made from sequentially harvested grapes. Shiraz wines were vinified from 60 kg grape triplicates. Following a berry ripening model the first harvest (H1) was 12 days from the plateau of berry sugar accumulation and the second harvest (H2), 24 days after the plateau. These results indicate significant modulation of wine volatiles as a consequence of harvest dates, by altering lipoxygenase derived compounds and yeast metabolism, irrespective of vineyard cultural practices, within the same warm to hot climatic region. In the third study the volatile composition of EVOO from five olive cultivars was investigated with GCxGC Tof-MS in association with multivariate analyses. A possible varietal differentiation according to the profiles of volatile compounds was affirmed by PCA and potential cultivar-specific biomarkers were identified.

Grapevines are being challenged by climate changes, forcing winemakers to implement irrigation systems to cope with excessive water stress. Previous studies focused on a small set of international varieties, and only few data are available for terroirs hosting cultivars with possibly different responses to drought stress. In this light, we monitored grapevine water status and grape’s physical and chemical composition, as well as concentration and structural characteristics of grape extractable polyphenols, in ten different Refosk vineyards located in the Classical Karst terroir during 2018 and 2019. Grapevines did not suffer severe stress during the two years, but their response to water shortage periods was highly heterogeneous, as pre-dawn (Ψpd) and minimum (Ψmin) leaf water potential significantly differed between vineyards, especially during the drier part of the season. Moreover, the timing of maximum water stress differed in the two years, as in 2019 longer water shortage periods and higher temperature occurred at flowering stage and before veraison, while in 2018 they were higher after veraison. These differences influenced berry’s quality, as titratable and malic acid concentration in juice, as well as total anthocyanin, total polyphenols and higher high molecular weight proanthocyanidins (HMWP) concentration in skins, were higher in 2019 than in 2018. Regarding seed proanthocyanidins, HMWP concentration, mean degree of polymerisation (mDP) and percentage of galloylation (G) in seeds were higher in 2018 than in 2019. The differences in water status measured in spatially close-related vineyards strongly support the importance of monitoring grapevines’ water status dynamics to design adequate and effective water management activities rather than relying on climate data solely. Moreover, the timing of water shortage periods also played a role in determining Refosk grape quality. Our analyses showed that the higher (but still moderate, with Ψpd and Ψmin mean values around −0.50 and −1.25 MPa, respectively) water stress between veraison and harvest occurred in 2018 might reduce Refosk grape acidity and increase concentration, polymerisation and galloylation of seed extractable proanthocyanidins.

Venenje ali dehidracija grozdja opisuje nepovratno in progresivno izgubo vode v grozdni jagodi, opisuje izgubo vode iz parenhimskih celic v mesu jagode. Spremembe zaradi dehidracije so opazne v velikosti, masi ter zunanjemu izgledu jagode. V diplomskem delu smo želeli preučiti vpliv dehidracije in sončnih ožigov v poznem dozorevanju na nekatere količinske in kakovostne parametre grozdja in vina sorte 'Barbera' (Vitis vinifera L.). Grozdne jagode smo ustrezno razdelili na dve skupini, na dehidrirane in nedehidrirane. Vpliv dehidracije grozdnih jagod na kemične in senzorične parametre smo preučevali z mikro-vinifikacijo v treh ponovitvah. Rezultati našega poskusa kažejo, da dehidracija v poznem dozorevanju vpliva na količino in kakovost grozdja in vina sorte 'Barbera' (Vitis vinifera L.). Ugotovili smo, da je bil primaren vzrok izgube mase jagod dehidracija grozdnih jagod v poznem dozorevanju in ne sončni ožig. Dehidracija jagod je značilno zmanjšala maso svežih jagod, kar je posledično vplivalo na manjši pridelek. Večjo vsebnost topne suhe snovi smo določili v grozdnem soku iz dehidriranih jagod. Prav tako smo v grozdnem soku iz dehidriranih jagod izmerili višje titrabilne kisline. Stopnja alkohola je bila višja v vinih, pridelanih iz dehidriranih jagod. Vina so se razlikovala tudi po vsebnosti skupnih antocianov, ti so bili višji v vinih iz dehidriranih jagod kar sovpada z izmerjenimi podatki o višji vsebnosti skupnih polifenolov v vinu iz dehidriranih jagod. Razlike smo opazili tudi v intenziteti barve vina, katera je bila višja v vinih iz dehidriranih jagod, medtem ko je bil odtenek barve višji v vinih iz nedehidriranih jagod. Senzorična analiza pridelanih vin je pokazala, da so bila vina, pridelana iz dehidriranih jagod, ocenjena kot bolj sadna (rdeče in temno sadje) in manj zelena, čeprav razlike niso bile statistično značilne. Dehidracija grozdnih jagod v poznem dozorevanju je vplivala na pridelek, vsebnost topne suhe snovi in skupnih kislin v grozdju ter značilno vplivala na alkohol in barvne parametre vina. Razlike v senzorični zaznavi so bile manj izrazite. Berry shrivelling or dehydration of grape describes an irreversible and progressive loss of the water in grape berries, it describes the loss from parenchymatic cells in the flesh of grape. Dehydration in our experiment was observed as a berry fresh weight loss and as visual modifications in appearance of the berries. In this work we intended to study the influence of dehydration and sunburn in the later ripening on the quantitative and qualitative parameters of 'Barbera' (Vitis vinifera L.) grapes and wine. Grape berries were appropriately classified into two groups, dehydrated and non-dehydrated berries. The effect of grape berry dehydration on wine chemical and sensory parameters was studied by performing micro-vinifications in triplicates. The results of our experiment show that dehydration in late ripening affects the quantity and quality of 'Barbera' (Vitis vinifera L.) grape and wine. We found out that the primary cause of observed weight loss and shrivelling in our study was dehydration in late ripening and not sun burns. Berry dehydration resulted in significant decrease in berry fresh weight, consequently influencing lower yields. Total soluble solids were higher in grape juice from dehydrated berries. We also found higher total acids in grape juice from dehydrated berries. Alcohol levels were higher in wines made from dehydrated berries. Wines also differed in the content of total anthocyanins which were higher in wines made from dehydrated berries coincidencing also with higher total polyphenols. The differences were also observed in the color intensity of wine which was higher in wines made from dehydrated berries, whereas hue was higher in wines made from non-dehydrated berries. The sensory analysis of the produced wines showed that wines from dehydrated berries were judged as fruitier (red and dark fruit) and less green, however the differences were not statistically significant. Berry dehydration in late ripening influenced yield, total soluble content and total acidity in grapes and also had significant influence on wine alcohol and colour parameters. The differences in wine sensory were less pronounced.