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The need to reduce the use of pesticides in viticulture is increasing the interest in wines produced using fungal-resistant grapevine varieties, which are characterized by relevant contents of both monoglucoside and diglucoside anthocyanins. Aging in wooden barrels induces oxygen permeation into wine, but little is known about diglucoside anthocyanin evolution. Cabernet cortis wine was subjected to addition of oxygen and oak chips, and the anthocyanin changes were followed for 1 month. Decreases of 90% total monoglucosides, 80% acylated monoglucosides, 65% diglucosides, and 90% acylated diglucosides were observed. Monoglucosides formed pyranoanthocyanins, and the lower steric hindrance favored their polymerization with flavanols. Instead, the decrease in diglucosides was correlated to the number of hydroxyl groups of ring B, indicating the predominant oxidation of aglycones. However, three flavonol-anthocyanin-diglucoside derivatives named (epi)catechin-ethyl-Mv-dihexoside, (epi)catechin-ethyl-Pn-dihexoside, and (epi)catechin-Mv-dihexoside A-type were identified in wine for the first time. These research findings are useful for tuning suitable oenological practices to stabilize the color of these wines (type of barrel, aging times, oxygenation practices) and lower the malvin content, which currently is recommended by the OIV at a maximum of 15 mg/L and is a critical issue for their commercialization.

Liquid chromatography/high-resolution mass spectrometry (LC/HRMS) can provide identification of grape metabolites which are variety markers. White grapes are poorer in polyphenolics, and the main secondary metabolites which contribute the sensorial characteristics of wines are the glycosidically bound volatile precursors and their aglycones. The profiles of three white grape juices (Pinot grigio, Garganega, and Trebbiano) were characterized by LC/HRMS, and 70 signals of putative glycosidic terpenols, norisoprenoids, and benzenoids were identified. Four signals found only in Pinot grigio corresponded to a norisoprenoid hexose-hexose, 3-oxo-α-ionol (or 3-hydroxy-β-damascone) rhamnosyl-hexoside, monoterpene-diol hexosyl-pentosyl-hexoside, and hexose-norisoprenoid; three signals were found only in Garganega (putative isopropyl alcohol pentosyl-hexoside, phenylethanol rhamnosyl-hexoside, and norisoprenoid hexose-hexose isomers), and a monoterpenol pentosyl-hexoside isomer only in Trebbiano. These variety markers were then investigated in juice blends of the three varieties. This approach can be used to develop control methods to reveal not-allowed grape varieties and practices in white wines winemaking.

A breeding program to produce new grape varieties tolerant to main vine fungal pathogens (Plasmopara viticola and Erysiphe necator) is carrying out by crossing Vitis vinifera cv. "Glera" with resistant genotypes such as "Solaris," "Bronner," and "Kunleany." Firstly, resistance gene-based markers analyses allowed the identification of five genotypes, which have inherited the resistance loci against mildews. To select those that also inherited the phenotype as close as possible to 'Glera' suitable to be introduced in the Prosecco wine production protocols, the grape glycosidic derivatives were studied by UHPLC/QTOF mass spectrometry. Targeted identification of the metabolites was performed using a database expressly constructed by including the glycosidic volatile precursors previously identified in grape and wine. A total of 77 glycosidic derivatives including many aroma precursors and some variety markers, were identified. Original resistant genotypes had distinct metabolomic profiles and different to 'Glera', while the crossings showed varying similarity degrees to V. vinifera parent. Findings demonstrated the Glera × Bronner and Glera × Solaris crossings are more suitable to produce high-sustainable Prosecco wines. Coupling of glycosidic volatile precursors profiling to multivariate statistical analysis was effective for phenotypic characterization of grapes and to evaluate their enological potential., (© 2023 John Wiley & Sons Ltd.)

Introduction: Prosecco wine production has been strongly extended in the last decade and several new clones have been introduced. "Glera" (minimum 85%) and "Glera lunga" are grape varieties of great economic impact used to produce Prosecco wines. Study of grape berry secondary metabolites is effective in the classification of vine varieties and clones. High-resolution mass spectrometry provides complete panorama of these metabolites in single analysis and coupling to statistical multivariate analysis is successfully applied in vine chemotaxonomy., Objectives: update and deepen the knowledge on the "Glera" and "Glera lunga" berry grapes chemotaxonomy and investigate some of the most produced and marketed clones by using the modern analytical and statistical tools., Methods: five clones of "Glera" and two of "Glera lunga" grown in the same vineyard with same agronomical practices were studied for three vintages. Grape berry metabolomics was characterized by UHPLC/QTOF and multivariate statistical analysis was performed on the signals of main metabolites of oenological interest., Results: "Glera" and "Glera lunga" showed different monoterpene profiles ("Glera" is richer in glycosidic linalool and nerol) and differences in polyphenols (catechin, epicatechin and procyanidins, trans-feruloyltartaric acid, E-ε-viniferin, isorhamnetin-glucoside, quercetin galactoside). Vintage affected the accumulation of these metabolites in berry. No statistical differentiation among the clones of each variety, was found., Conclusions: Coupling HRMS metabolomics/statistical multivariate analysis enabled clear differentiation between the two varieties. The examined clones of same variety showed similar metabolomic profiles and enological characteristics, but vineyard planting using different clones can result in more consistent final wines reducing the vintage variability linked to genotype × environment interaction., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Somatic mutations in Vitis spp. are relatively frequent and can generate new agronomically interesting phenotypes. We report the discovery, genetic and chemical characterization of 'Glera rosa', a mutant for the berry skin colour of 'Glera', the main white cultivar used to produce Prosecco wine., Results: We ascertained the relationship between the skin colour of 'Glera rosa' and the polymorphisms in the Myb-gene transcription factors involved in polyphenol biosynthesis. We established that VvMybA1 was homozygous (VvMybA1a/VvMybA1a) in 'Glera' but heterozygous (VvmybA1a/VvmybA1b) in the 'Glera rosa' mutant. We verified that the VvMybA1a non-functional allele contained Grapevine Retrotransposon 1 (Gret1), while in the VvmybA1b allele Gret1 was missing, and the gene function was partially restored. The effects of mutation on 'Glera rosa' grape metabolites were studied by high-resolution mass spectrometry and gas chromatography/mass spectrometry analysis. Fifteen anthocyanins and five unique flavonols were found in the 'Glera rosa' mutant. The mutation also increased the contents of trans-resveratrol and its derivatives (i.e., piceatannol, E-ε-viniferin, cis- and trans-piceid) and of some flavonols in grape. Finally, the mutation did not significantly affect the typical aroma precursors of Glera grape such as glycosidic monoterpenes, norisoprenoids and benzenoids., Conclusion: 'Glera rosa' could be an interesting genetic source for the wine industry to produce Prosecco DOC rosé typology (made by adding up to 15% of 'Pinot Noir'), which was introduced to the market in 2020 with a worldwide massive success. © 2022 Society of Chemical Industry., (© 2022 Society of Chemical Industry.)

Introduction: The biochemical diversity of flavonoids is based on glycosylation, methylation, acylation, and many other modifications of the flavonoid backbone. Liquid chromatography coupled to high-resolution mass spectrometry demonstrated to be a powerful approach to gain new insights into the flavonoid composition of many plant species, including grapes., Objectives: Among different metabolomic approaches, suspect screening analysis relies on the construction of a specific database and on ultra-high performance liquid chromatography/quadrupole time-of-flight (UHPLC/QTOF) analysis to find new compounds of oenological interest., Methods: A homemade database containing mass data information retrieved from the literature specific for plant flavonoid derivatives (GrapeFlavMet) was constructed. Tandem mass spectrometry analysis of V. vinifera and hybrid grape extracts was performed, and MS/MS fragmentation allowed to assign the putative flavonoid chemical structure to various identification levels, as established by the Metabolomics Standard Initiative., Results: By this approach, putative flavonoid derivatives with different glycosylation and acylation patterns were identified. They include three pentoside derivatives of tetrahydroxy-flavone, tetrahydroxy-flavanone and myricetin isomers, a putative dihydrorhamnetin hexoside derivative, three cinchonain isomers (phenylpropanoid-substituted flavan-3-ols with antidiabetic properties), and two syringetin isomer derivatives (acetyl- and p-coumaroyl-hexoside). Two acetyl-hexoside derivatives of dihydrorhamnetin and pentahydroxy-methoxy-flavanone, and three derivatives of tetrahydroxy-dimethoxy-flavanone (acetyl, p-coumaroyl, and caffeoyl-hexoside) were tentatively annotated., Conclusions: Most of the compounds were identified in grape for the first time, while two putative syringetin derivatives previously proposed in the literature were confirmed. These findings deepen the current knowledge on grape flavonoids, suggesting more connections at the biochemical level., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Along with the ongoing climate change, drought events are predicted to become more severe. In this context, the spray-induced gene silencing (SIGS) technique could represent a useful strategy to improve crop stress resilience. A previous study demonstrated that the Arabidopsis mutants for a glutathione S-transferase (GST) gene had increased abscisic acid (ABA) levels and a more activated antioxidant system, both features that improved drought resilience. Here, we used SIGS to target a putative grape GST gene (VvGST40). Then, ecophysiological, biochemical and molecular responses of 'Chardonnay' cuttings were analysed during a drought and recovery time-course. Gas exchange, ABA and t-resveratrol concentration as well as expression of stress-related genes were monitored in not treated controls, dsRNA-VvGST40- and dsRNA-GFP- (negative control of the technique) treated plants, either submitted or not to drought. VvGST40-treated plants revealed increased resilience to severe drought as attested by the ecophysiological data. Analysis of target metabolites and antioxidant- and ABA-related transcripts confirmed that VvGST40-treated plants were in a priming status compared with controls. SIGS targeting an endogenous gene was successfully applied in grapevine, confirming the ability of this technique to be exploited not only for plant protection issues but also for functional genomic studies., (© 2021 John Wiley & Sons Ltd.)

Phenolics are ubiquitous compounds that represent the most abundant and diverse class of plant metabolites. From an analytical point of view, phenolics can be divided into soluble phenolics such as phenolic acids, phenylpropanoids, flavonoids and quinones, and nonsoluble compounds such as proanthocyanidins, lignins, and cell wall-bound hydroxycinnamic acids. Extraction of phenolics from the sample material is the first step toward their analysis. Biochemical methods for determination of total phenolics content were widely used in the past but modern chromatographic and mass spectrometric methods for identification and quantification of individual compounds are available in recent years. In this chapter, we describe methods for phenolic compounds extraction used in our laboratories from berries of Vitis vinifera and analytical methods including HPLC coupled to DAD detector and Q-TOF LC/MS for their analysis., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

In the Valpolicella area (Verona, Italy) Vitis vinifera cv. Corvina is the main grape variety used to produce Amarone wine. Before starting the winemaking process, the Corvina grapes are stored in a withering (i.e., dehydrating) warehouse until about 30% of the berry weight is lost (WL). This practice is performed to concentrate the metabolites in the berry and enrich the Amarone wine in aroma and antioxidant compounds. In compliance with the guidelines and strict Amarone protocol set by the Consorzio of Amarone Valpolicella, withering must be carried out by setting the grapes in a suitable environment, either under controlled relative air humidity (RH) conditions and wind speed (WS)-no temperature modification is to be applied-or, following the traditional methods, in non-controlled environmental conditions. In general, the two processes have different dehydration kinetics due to the different conditions in terms of temperature, RH, and WS, which affect the accumulation of sugars and organic acids and the biosynthesis of secondary metabolites such as stilbenes and glycoside aroma precursors. For this study, the two grape-withering processes were carried out under controlled (C) and non-controlled (NC) conditions, and the final compositions of the Corvina dried grapes were compared also to evaluate the effects on the organoleptic characteristics of Amarone wine. The findings highlighted differences between the two processes mainly in terms of the secondary metabolites of the dried grapes, which affect the organoleptic characteristics of Amarone wine. Indeed, by the sensory evaluation, wines produced by adopting the NC process were found more harmonious, elegant, and balanced. Finally, we can state how using a traditional system, grapes were characterised by higher levels of VOCs (volatile compounds), whilst wines had a higher and appreciable complexity and finesse.

The Italian grape pomace distillate grappa is often refined by ageing in wooden barrels. Chemical changes of the volatile profile of two samples produced from a Cabernet Sauvignon/Merlot blend and Prosecco pomace both at two ethanol contents (55% and 68%) were studied during one-year ageing in cherry and oak barriques. Grappa variety, ethanol content and barrel type strongly affected the volatiles profile of the distillates. Oak-aged grappa contained 10-fold the wood volatiles of the cherry-aged one, but the latter had higher levels of syringaldehyde, coniferaldehyde, and 3,4,5-trimethoxyphenol; 55% ethanol extracted higher levels of wood compounds and ethoxy-compounds were higher in the 68%-ethanol distillates. Prosecco grappa extracted higher wood compounds and showed no significant changes in the levels of fruity/floral esters and terpenols. Findings of this study can be also useful in the development of new ageing processes of distillates for which cherry barrels are still not used (e.g., brandy and whisky)., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Grape dehydration is an oenological process used for production of high-quality reinforced and sweet wines. High-resolution mass spectrometry (ultrahigh-performance liquid chromatography/quadrupole time-of-flight [UHPLC/QTOF]) was used to deepen the characterization of some flavonoids previously proposed in Corvina and Raboso Piave withered grapes. By performing a targeted data analysis workflow and orthogonal identification approaches (tandem mass spectrometry [MS/MS]), in silico fragmentation, and calculation of putative retention time), elucidation on the structures of six compounds previously proposed was achieved (taxifolin-pentoside, two tetrahydroxyflavanone-hexoside derivatives, a tetrahydroxy-dimethoxyflavanone-hexoside derivative, a pentahydroxyflavone, and peonidin-O-pentoside); and the structures of four putative new grape flavonoids were characterized (dihydromyricetin-O-hexoside, taxifolin-di-O-hexoside, isorhamnetin, and a pinoquercetin isomer). Findings enlarge the panorama of flavonoids in grape and of their possible biosynthetic pathways., (© 2020 John Wiley & Sons, Ltd.)

Grapes contain many flavonoid and non-flavonoid compounds with anticancer effects. In this work we fully characterized the polyphenolic profile of two grape skin extracts (GSEs), Autumn Royal and Egnatia, and assessed their effects on Polyunsaturated Fatty Acid (PUFA) membrane levels of Caco2 and SW480 human colon cancer cell lines. Gene expression of 15-lipoxygenase-1 (15-LOX-1), and peroxisome proliferator-activated receptor gamma (PPAR-γ), as well as cell morphology, were evaluated. The polyphenolic composition was analyzed by Ultra-High-Performance Liquid Chromatography/Quadrupole-Time of Flight mass spectrometry (UHPLC/QTOF) analysis. PUFA levels were evaluated by gas chromatography, and gene expression levels of 15-LOX-1 and PPAR-γ were analyzed by real-time Polymerase Chain Reaction (PCR). Morphological cell changes caused by GSEs were identified by field emission scanning electron microscope (FE-SEM) and photomicrograph examination. We detected a different profile of flavonoid and non-flavonoid compounds in Autumn Royal and Egnatia GSEs. Cultured cells showed an increase of total PUFA levels mainly after treatment with Autumn Royal grape, and were richer in flavonoids when compared with the Egnatia variety. Both GSEs were able to affect 15-LOX-1 and PPAR-γ gene expression and cell morphology. Our results highlighted a new antitumor mechanism of GSEs that involves membrane PUFAs and their downstream pathways.

The currently accepted paradigm is that fruits and vegetables should be consumed fresh and that their quality deteriorates during storage; however, there are indications that some metabolic properties can, in fact, be improved. We examined the effects of low temperature and high-CO 2 conditions on table grapes, Vitis vinifera L. cv. 'Superior Seedless'. Berries were sampled at harvest (T0) and after low-temperature storage for 6 weeks under either normal atmosphere conditions (TC) or under an O 2 level of 5 kPa and elevated CO 2 levels of 5, 10 or 15 kPa (T5, T10, T15). Accumulation of 10 stilbenes, including E-ε-viniferin, E-miyabenol C and piceatannol, significantly increased under TC treatment as compared to T0 or T15. Sensory analysis demonstrated that elevated CO 2 elicited dose-dependent off-flavor accumulation. These changes were accompanied by an accumulation of 12 volatile metabolites, e.g., ethyl acetate and diacetyl, that imparted disagreeable flavors to fresh fruit. Transcriptome analysis revealed enrichment of genes involved in pyruvate metabolism and the phenylpropanoid pathway. One of the transcription factors induced at low temperature but not under high CO 2 was VvMYB14, which regulates stilbene biosynthesis. Our findings reveal the potential to alter the levels of targeted metabolites in stored produce through understanding the effects of postharvest treatments.

Introduction: Grape varieties allowed to produce Amarone della Valpolicella and Recioto DOCG wines are strictly regulated by their disciplinary of production. These are Corvina Veronese and Corvinone grapes, to a lesser extent also Rondinella can be used. The use of other varieties, is not allowed., Objectives: To identify chemical markers suitable to reveal addition of two not allowed grape varieties to the Corvina/Corvinone blend, such as Primitivo or Negro Amaro., Methods: The identification of the secondary metabolites of the four grape varieties was conducted by high-resolution mass spectrometry (HRMS) metabolomics. By using the signals of these metabolites the indexes able to identify the presence of Primitivo or Negro Amaro grapes in the Corvina/Corvinone 1:1 blend were calculated., Results: Indexes of laricitrin (Lr), delphinidin (Dp), and petunidin (Pt) signals were effective to identify the use of 10% Primitivo, while α-terpineol pentosyl-hexoside and linalool pentosyl-hexoside reveal the presence of Negro Amaro in the grape blend., Conclusions: Varietal markers useful to detect the presence of Primitivo and Negro Amaro in the grape blend were identified by HRMS metabolomics, a method suitable to check the identity of grapes on arrival at the winery, as well as the fermenting musts. The effectiveness of the identified markers in the final wines have to be confirmed. Potentially, a similar approach can be used to reveal analogous frauds performed on other high-quality wines.

Monoterpene-glycosides are important aroma precursors that, undergo hydrolysis, confer intense floral notes to the wines. Therefore, the knowledge of the nature of the sugar residues and the structure of these molecules is of great interest. In present study, liquid chromatography (LC) separation coupled with different mass spectrometry (MS) experiments for the characterization of these compounds were explored. The LC parameters were tuned to optimize the resolution between the analytes present in grape sample extracts. Twenty principal peaks with a relative abundance >1% were selected and divided in 4 classes characterized by different molecular weight. In general, positive ionization of the studied compounds displayed the [M + NH 4 ] + ion as base peak. On the contrary, a distribution between [M + Cl] - and [M + HCOO] - species was observed in negative ion mode. However, a clear differentiation between the studied compounds was only possible by combining both LC and tandem MS (MS/MS). Indeed, by applying a series of energy resolved MS/MS experiments and monitoring both positive and negative ions, a structural characterization of the analytes was achieved. The proposed LC-MS/MS approach provided the profile of monoterpenol-diglycosides and allowed the identification of a series of isobaric terpene-diglycosides in grape. The study of their MS/MS spectra indicated the structure of geranic and/or nerolic acid aglycones. To verify the interest of studied compounds, a preliminary evaluation of the intensity of signals of these glycosides were carried out. The obtained results showed a significant difference between the grape samples collected in two different vintages., (© 2018 John Wiley & Sons, Ltd.)

Background: Grape withering is a process used to produce reinforced wines and raisins. Dehydration is usually carried out postharvest by keeping ripe grapes in special warehouses in controlled conditions of temperature, relative humidity (RH) and air flow. Alternatively, grape clusters can be left on the vines after the canes have been pruned. In general, dehydration increases stilbenes in grape, but there are few studies on the effects of on-vine withering. The stilbene profiles of Raboso Piave grape during postharvest and on-vine dehydration were studied here., Results: High-resolution mass spectrometry (MS) was used to identify 19 stilbenes, including resveratrol monomers, dimers (viniferins), oligomers and glucoside derivatives. The two dehydration methods generally had different effects on the above nutraceuticals in grape. The samples kept in warehouses revealed significant increases in Z-ω-viniferin, E-ϵ-viniferin, δ-viniferin and another resveratrol dimer which were not observed in the plants. Trans-Resveratrol increased significantly only in samples dehydrated in the warehouse at 21 °C and 60-70% RH., Conclusion: The findings increase knowledge of stilbene composition in grapes subjected to withering on-vine. The choice of dehydration method affects the contents of these nutraceuticals in the grape and consequently in wines. Reasonably, it could also affect other secondary metabolites important for wine quality. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)

Previous studies showed that hybrid grapes often have qualitatively and quantitatively higher polyphenolic contents than the common V. vinifera grape varieties. In general, these compounds are studied for grape chemotaxonomy and for nutraceutical purposes due to their relevant antioxidant activity. Non-anthocyanic flavonoid composition of five red hybrid grape varieties produced by crossing of V. vinifera, V. aestivalis, V. cinerea, V. berlandieri, V. labrusca, V. lincecumii, and V. rupestris were studied by liquid chromatography/high-resolution mass spectrometry. Thirty-one compounds were identified, including methylnaringenin, a tetrahydroxy-dimethoxyflavanone-hexoside, two flavonols (quercetin and a pentahydroxyflavone isomer), 20 glycoside flavonols (four quercetin, two myricetin, two kaempferol, three isorhamnetin, one laricitrin, two syringetin, one kaempferide and two dihydroflavonol derivatives; myricetin-glucoside-glucuronide; myricetin-diglucoside; syringetin-dihexoside), three flavan-3-ols (-)-epicatechin, (+)-catechin, (-)-epicatechin gallate) and four proantocyanidins (procyanidin B1, procyanidin B2, procyanidin B3 or B4/B5, procyanidin T2 or T3/T4/C1). Seibel 19881, Seyve Villard 12-347 and Seyve Villard 29-399 were particularly rich in polyphenols. These findings emphasize that these grapes are especially interesting for the production of antioxidant extracts for nutraceutical and pharmaceutical uses.

Rationale: Grape polyphenols are antioxidant compounds, markers in vine chemotaxonomy, and involved in color stabilization of red wines. Sugar acylation usually confers higher stability on glycoside derivatives and this effect is enhanced by an aromatic substituent such as p-coumaric acid. Until now, only p-coumaroyl anthocyanins have been found in grape., Methods: A method of 'suspect screening analysis' by ultra-high-performance liquid chromatography/high-resolution mass spectrometry (UHPLC/QTOFMS) has recently been developed to study grape metabolomics. In the present study, this approach was used to identify new polyphenols in grape by accurate mass measurement, MS/MS fragmentation, and study of correlations between fragments observed and putative structures., Results: Three putative p-coumaroyl flavonoids were identified in Raboso Piave grape extract: a dihydrokaempferide-3-O-p-coumaroylhexoside-like flavanone, isorhamnetin-3-O-p-coumaroylglucoside, and a chrysoeriol-p-coumaroylhexoside-like flavone. Accurate MS provided structural characterization of functional groups, and literature data indicates their probable position in the molecule. A fragmentation scheme is proposed for each compound., Conclusions: Compounds were identified by overlapping various analytical methods according to recommendations in the MS-based metabolomics literature. Stereochemistry and the definitive position of substituents in the molecule can only be confirmed by isolation and characterization or synthesis of each compound. These findings suggest addressing research of acylated polyphenol glycosides to other grape varieties., (Copyright © 2015 John Wiley & Sons, Ltd.)

Grape flavonols are involved in the phenomenon of copigmentation in red wines. These compounds are characterised by nutraceutical properties, have antioxidant activity and are studied for chemotaxonomy of grapes. In general, hybrid grapes are characterised by presence of polyphenols often qualitatively and quantitatively different from Vitis vinifera varieties. In this work, flavonols of 34 hybrid grape varieties (22 red and 12 white) produced by crossing of V. vinifera, Vitis riparia, Vitis labrusca, Vitis lincecumii and Vitis rupestris species, were studied. Compounds were characterised by combining different liquid chromatography/mass spectrometry (LC/MS) methods: precursor-ion and neutral-loss multiple-reaction-monitoring (MRM), and high-resolution mass spectrometry. Twenty-four glycoside flavonols were identified, including 4 quercetin, 5 myricetin, 4 kaempferol, 3 isorhamnetin, 2 laricitrin, 3 syringetin and 3 dihydroflavonol derivatives; myricetin hexoside-glucuronide, myricetin O-di-hexoside, syringetin O-di-hexoside, isorhamnetin rutinoside and kaempferol rutinoside were found in grape for the first time. Statistical analysis (PCA and cluster analysis) divided the samples in four groups on the basis of their flavonol profiles., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Carotenoid-derived aroma compounds play an important role in the composition of aroma and grapes, and consequently of wine. The volatile composition of forty-five grape varieties harvested in 2011 and 2012 was investigated by solid phase extraction of samples and gas chromatography-mass spectrometry (GC-MS) analysis. In grape extracts of cultivars Barbera, Refosco dal Peducolo Rosso, Ribolla gialla and Rossese, the C9-norisoprenoid compound β-isophorone (3,5,5-trimethyl-3-cyclohexen-1-one) was found and quantified. This carotenoid-derived compound is characterised by a saffron aroma and is here reported in grape for the first time., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Grape is qualitatively and quantitatively very rich in polyphenols. In particular, anthocyanins, flavonols and stilbene derivatives play very important roles in plant metabolism, thanks to their peculiar characteristics. Anthocyanins are responsible for the color of red grapes and wines and confer organoleptic characteristics on the wine. They are used for chemotaxonomic studies and to evaluate the polyphenolic ripening stage of grape. They are natural colorants, have antioxidant, antimicrobial and anticarcinogenic activity, exert protective effects on the human cardiovascular system, and are used in the food and pharmaceutical industries. Stilbenes are vine phytoalexins present in grape berries and associated with the beneficial effects of drinking wine. The principal stilbene, resveratrol, is characterized by anticancer, antioxidant, anti-inflammatory and cardioprotective activity. Resveratrol dimers and oligomers also occur in grape, and are synthetized by the vine as active defenses against exogenous attack, or produced by extracellular enzymes released from pathogens in an attempt to eliminate undesirable toxic compounds. Flavonols are a ubiquitous class of flavonoids with photo-protection and copigmentation (together with anthocyanins) functions. The lack of expression of the enzyme flavonoid 3',5'-hydroxylase in white grapes restricts the presence of these compounds to quercetin, kaempferol and isorhamnetin derivatives, whereas red grapes usually also contain myricetin, laricitrin and syringetin derivatives. In the last ten years, the technological development of analytical instrumentation, particularly mass spectrometry, has led to great improvements and further knowledge of the chemistry of these compounds. In this review, the biosynthesis and biological role of these grape polyphenols are briefly introduced, together with the latest knowledge of their chemistry.

The ability of grapevine to activate defense mechanisms against some pathogens has been shown to be linked to the synthesis of stilbenes by the plant (inducible viniferins). Metabolized viniferins may also be produced or modified by extracellular enzymes released by the pathogen in an attempt to eliminate undesirable toxic compounds. Due to the important properties of resveratrol, there is increasing interest in producing foods with higher contents of this compound and higher nutritional value. The production of high resveratrol-containing grapes and wines relies on quality-oriented viticulture (suitable terroirs, sustainable cultural practices) and wine-making technologies which avoid degradation of the compound. The technique of skin extraction and enzymatic hydrolysis of glucoside forms in wine-making plays an important role in resveratrol wine concentration. Other factors affecting its final concentration and balance in wine are conditions for promoting trans-cis isomerization of aglycones, the type of yeast used, and the presence of lactic bacteria with β-glucosidase activity. In general, the enological practices commonly used to stabilize wine after fermentation do not significantly affect resveratrol concentrations, which show considerable stability.

Triglyceride profile of seed oil samples from 32 hybrid grape varieties not studied before was investigated. A new method for the analysis of triacylglycerols (TAGs) has been developed based on the direct infusion in the electrospray ionization (ESI) source and employing tetrahydrofuran/methanol/water (85:10:5 v|v|v) as solvent; the formation of [M + Na](+) ions in high yield has been observed. TAGs were identified by ESI-tandem mass spectrometry analysis, and the matrix-assisted-laser-desorption-ionization and time-of-flight profile of samples was determined. Six were the principal TAGs identified in seed oil: trilinolein (LLL) was the most abundant (43%), followed by dilinoleoyl-oleoylglycerol (LOL, 23%), and dilinoleoyl-palmitoylglycerol (LPL, 15%). Compounds present in lower concentration were LSL and LOO (11%), LOP (6%), and LSP (2%). Compared with seed oils produced from V. Vinifera grapes, some significant differences in the relative abundances of TAGs were found, in particular hybrid grape seed oils showed higher LOL and lower LPL content, respectively. Among the samples studied, a particularly high content of LLL (rich in unsaturated fatty acids) was found in seed oils from two red varieties., (Copyright © 2012 John Wiley & Sons, Ltd.)

The anthocyanins of 21 hybrid red varieties produced by crossing V. vinifera, V. riparia, V. labrusca, V. lincecumii and V. rupestris species, the profiles for which have not yet been reported, were studied. Profiles were determined by LC/DAD, and identification of single anthocyanins was confirmed by LC/MS precursor-ion analysis. Anthocyanidin precursors (pelargonidin at m/z 271, dephinidin at m/z 303, cyanidin at m/z 287, petunidin at m/z 317, peonidin at m/z 301, and malvidin at m/z 331) and precursors of monoglucoside compounds allowed 24 different compounds to be identified. Analysis of precursor ions of monoglucoside anthocyanins at low capillary voltage revealed the signals of diglucosides only, providing a very selective method for analysis of diglucoside anthocyanins in grape. According to anthocyanin profile, the samples were subdivided into two groups: one characterized by the substantial presence of diglucoside compounds (particularly Seyve Villard 23-399 and Seyve Villard 23-369) and one by the scarce presence or practical absence of diglucosides (Seibel 10878, Burdin 4077, and Galibert 238-35). Particularly interesting for producing anthocyanin for the natural colorant industry were the varieties Siebel 8357, Bacò 30-12 and Terzi 100-31., (Copyright © 2011 Elsevier B.V. All rights reserved.)

DNA studies supported by matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis of seed proteins showed that the Vitis vinifera red grape variety Raboso Veronese is the progeny of a spontaneous cross between Raboso Piave (red) and Marzemina Bianca (white) varieties. In the present work, the main secondary grape metabolites of Raboso varieties were studied, and their enological potential was evaluated and compared with that of other red varieties reported in the literature. In general, Raboso grapes had high flavonoid contents and high percentages of polyphenols extractable in winemaking and substantial contents of norisoprenoid aroma precursors. Raboso Veronese stood out for its high content of cyanidin and had higher (+)-catechin and (-)-epicatechin contents than Raboso Piave and abundant quercetin glucoside, indicating substantial plant biosynthesis toward compounds dihydroxylated in the B-ring. Study of secondary grape metabolites is confirmed as an effective tool in differentiating similar varieties, in particular on the basis of polyphenol profiles.

Two Raboso cultivars, i.e. Raboso Veronese and Raboso Piave, are two black Vitis vinifera varieties. A genetic study suggested that Raboso Veronese is the progeny of a spontaneous cross between Raboso Piave and Marzemina Bianca cultivars. Parental relationships are usually investigated by genetic studies, which are effective to establish genetic links among different cultivars. Considering that proteome is the genome expression, in this article we evaluated the power of seed protein profiles obtained by matrix-assisted laser desorption/ionization (MALDI)/MS for parentage investigation. The three cultivars lead to very similar spectra with differences in the relative intensity of the most abundant species and the presence of very weak specific ions. In order to evaluate the analytical significance of these aspects, the variability due to instrumental factors and due to different harvesting areas and years of the same cultivars have been considered and measured by the calculation of discrepancy factor values. On one hand, the results obtained can be considered a valid confirmation of the genomic findings, whereas on the other hand, the results provide evidence for the ability of MALDI/MS to individuate minor differences in protein profiles of complex protein mixtures., (2010 John Wiley & Sons, Ltd.)

2'-Aminoacetophenone (o-AAP) was identified as the main cause of the aging note called 'hybrid note' or 'foxy smell' which is typical of non-Vitis vinifera grapes. Together with methyl anthranilate (MA), this compound contributes to the typical foxy taint of wines made with non-Vitis vinifera grapes. 3-Alkyl-2-methoxypyrazines in grapes, with their herbaceous note and very low sensory thresholds, contribute to the aroma of several wines. In this study, a solid-phase microextraction gas chromatography/ion trap tandem mass spectrometry (SPME-GC/IT-MS/MS) method for simultaneous detection of o-AAP, MA and ethyl-, isopropyl-, sec-butyl- and isobutylmethoxypyrazine in grape juice was developed. The method was applied to the study of several grape juices: the time required for analysis was less than 24 min, and the method was considered to be suitable for analysis of 'foxy compounds' and methoxypyrazines in grape juice. The high levels of MA and o-AAP found in Clinton and Siebel grapes confirmed the 'hybrid' character of these varieties., (Copyright 2010 John Wiley & Sons, Ltd.)

In a previous work, direct-infusion electrospray ionization ion trap tandem mass spectrometry (ESI-IT-MS/MS) was applied to the study of anthocyanins in extracts from the skins of Clinton grapes, a non-Vitis vinifera red grape variety qualitatively and quantitatively rich in anthocyanins. A good characterization of anthocyaninins was obtained, but it was impossible to differentiate some compounds with the same nominal mass but with different elemental composition. In this work, the capabilities of quadrupole time-of-flight mass spectrometry (QTOF-MS) coupled with Chip-liquid chromatography (LC-Chip) were applied to the study of Clinton anthocyanins and this method provided the complete sample anthocyanin fingerprint in less than 5 min. Multi-stage mass spectrometry (MS(n); n >2) was not necessary to identify isobaric compounds, nor were deuterium-exchange experiments necessary to distinguish between compounds containing the same aglycone. The fast separation bypasses the problem of petunidin-3-O-(6-O-acetyl)monoglucoside and delphinidin-3,5-O-diglucoside quantification, present in the direct-infusion ESI-ITMS approach, due to overlapping with matrix interferences.

Until now the study of pathogenic related proteins in grape juice and wine, performed by ESI-MS, LC/ESI-MS, and MALDI/MS, has been proposed for differentiation of varieties. In fact, chitinases and thaumatin-like proteins persist through the vinification process and cause hazes and sediments in bottled wines. An additional instrument, potentially suitable for the grape varieties differentiation, has been developed by MALDI/MS for the grape seed protein analysis. The hydrosoluble protein profiles of seeds extract from three different Vitis vinifera grape (red and white) varieties were analyzed and compared. In order to evaluate the environmental conditions and harvest effects, the seed protein profiles of one grape variety from different locations and harvests were studied., ((c) 2008 John Wiley & Sons, Ltd.)

A new sensitive and selective analytical method for the analysis of ochratoxin A (OTA) in grape and wine was developed by coupling liquid chromatography and surface activated chemical ionization and mass spectrometry with multistage fragmentation (LC/SACI-MS(3)). A high flow gradient was used to strongly reduce the matrix effect phenomenon, and the wine sample was directly injected onto the chromatographic column without sample pre-concentration or purification steps. The amount of OTA was determined for two grape extracts and the amount of OTA, percent accuracy error and percent precision error were analyzed for 15 wine samples. An excellent limit of detection of 0.02 ng/mL was achieved, and the limit of quantification was at least 20-fold lower than the maximum legal limit for OTA (2 ppb). Due to the low limit of quantification, this novel method is a potential tool for official OTA screening purposes., (Copyright 2007 John Wiley & Sons, Ltd.)

Wine proteins play an important role in the quality of wine, because they affect taste, clarity and stability of product. The majority of wine proteins are in the range of 20-30 kDa. Different mass spectrometry (MS) techniques have been successfully applied to study the grape and wine proteins. By liquid chromatography (LC) electrospray ionization (ESI) MS and nano-LC/MS, nine dipeptides and 80 peptides were unambiguously identified in Champagne and Sauvignon Blanc wines, respectively. Using matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) and surface-enhanced laser desorption/ionization TOF, the protein and peptide fingerprints in Chardonnay, Sauvignon Blanc and Muscat of Alexandria wines were determined. MALDI-TOF identified the mesocarp proteome of six Vitis grape varieties. Proteins in different grape tissue extracts were also studied. The major grape pathogenic-related proteins are chitinases and thaumatin-like proteins, which both persist through the vinification process and cause hazes and sediments in bottled wines. ESI-MS, LC/ESI-MS and MALDI-TOF analysis of these proteins in grape and wine were also used to characterize different grape varieties.