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Background Beta-Glucosidases (3.2.1.21) play essential roles in the removal of nonreducing terminal glucosyl residues from saccharides and glycosides. However, the full potential and different applications of recombinant high-yield microbial β-glucosidase-producing systems remain to be tackled. Results A β-glucosidase gene designated as Mg132 was isolated from a coral microorganism by high-throughput sequencing and functional screening. The deduced amino acid sequences of Mg132 showed a highest identity of 97% with β-glucosidase predicted in the GenBank database. This gene was cloned and overexpressed in Escherichia coli BL21 (DE3) for the first time. The optimal pH and temperature of purified recombinant Mg132 were 8.0 and 50 °C, respectively. It exhibited a high level of stability at high concentration of glucose and ethanol, and glucose concentrations below 300 mM distinctly stimulated p-nitrophenyl-β-D-glucopyranoside hydrolysis, reaching 200% at 15% ethanol. The Km and Vmax values were 0.293 mM and 320 μmol min-1 mg-1 , respectively, while using p-nitrophenyl-β-D-glucopyranoside as a substrate. Wine treated with Mg132 had an obvious positive catalytic specificity for glycosides, which give a pleasant flavor of temperate fruity and floral aromas. The total concentration of fermentative volatiles was 201.42 ± 10.22 μg·L-1 following Mg132 treatment and 99.21 ± 7.72 μg·L-1 in control samples. Conclusion Good tolerance of winemaking and aroma fermentative properties suggest that Mg132 has potential application in aroma enhancement in wine for the further study. This article is protected by copyright. All rights reserved.

Background Flavored wine is a type of specialized wine fortified with flavor additives such as herbs, spices, fruits and other natural flavorings, which has attracted increasing attention. In practice, the addition of flavor substances in winemaking is strictly regulated in many countries. Scope and approach This review evaluates traditional flavored wines in terms of history, botanical recipe, processing technique and sensory quality, and explores emerging flavored wines in the aspects of flavor additives, aroma profile and sensory properties. Additionally, the interactions between phenolic compounds and aroma compounds in flavored wines and their impacts on product quality are also discussed. Key findings and conclusions Traditional flavored wine, such as Vermouth, Bermet and Retsina, is among the most renowned alcoholic drinks. Basically, it is a blend of wine, botanical extracts, sugar and alcohol. Different parts (peel, seeds, flower heads, etc.) of aromatic plants (wormwood, cinchona, pine resin, etc.) are adopted as flavor additives, but with different combinations and proportions in recipe from company to company. At present, research on novel flavored wine is still at the early stage, although the inclusion of Ganoderma lucidum extract, Gentiana lutea root powders, grape skin extract, fruit juice, rice, dextrin, water and oak chips in winemaking have been proved to be successful in enhancing the aroma/flavor of wine and improving the mouthfeel. Addition of non-grape materials could introduce additional phenolics and aromatic compounds to the wine matrix, which is a critical factor impacting the flavor and palate of the flavored wine. Importantly, phenolics from non-grape materials may interact with saliva and oral mucosa and therefore has a prominent impact on the wine aroma volatility and thus wine organoleptic quality. In general, both traditional flavored wine and novel flavored wine are specially fortified wine characterized by the unique aroma and flavor of additional flavorings such as herbs, spices, fruits and other natural flavoring substances. This review provides comprehensive information on both old-fashioned and emerging flavored wines, which may trigger further investigation to exploit the potential of natural flavorings in winemaking.

The synthesis of volatile organic compounds (VOCs) in plants is triggered in response to external stimuli, and these compounds can migrate to distal tissues and neighbouring receivers. Although grapevine VOCs responsible for wine aroma and plant–insect communications are well characterized, functional properties of VOCs produced in response to phytopathogens, beneficial microorganisms, resistance inducers, and abiotic factors have been less studied. In this review, we focused on the emission patterns and potential biological functions of VOCs produced by grapevines in response to stimuli. Specific grapevine VOCs are emitted in response to the exogenous stimulus, suggesting their precise involvement in plant defence response. VOCs with inhibitory activities against pathogens and responsible for plant resistance induction are reported, and some of them can also be used as biomarkers of grapevine resistance. Likewise, VOCs produced in response to beneficial microorganisms and environmental factors are possible mediators of grapevine–microbe communications and abiotic stress tolerance. Although further functional studies may improve our knowledge, the existing literature suggests that VOCs have an underestimated potential application as pathogen inhibitors, resistance inducers against biotic or abiotic stresses, signalling molecules, membrane stabilizers, and modulators of reactive oxygen species. VOC patterns could also be used to screen for resistant traits or to monitor the plant physiological status.

Volatile constituents in jambolan [Syzgium cumini (L.) Skeels] wine were isolated by headspace–solid phase microextraction (HS–SPME) and analyzed by gas chromatography-flame ionization detector (GC–FID), gas chromatography-mass spectrometry (GC–MS), and gas chromatography–olfactometry (GC–O). The composition of the jambolan wine included 52 esters, 20 terpenes, 13 alcohols, 12 acids, 11 aldehydes, 4 ketones, 4 oxides, and 5 miscellaneous compounds. Aroma extract dilution analysis and odor activity units were used for the determination of odor-active compounds. A total of 19 odor-active compounds were found as odor-active volatiles, from which (E)-β-ionone, phenylacetaldehyde, ethyl acetate, ethyl hexanoate, and ethyl benzoate were the most important. The similar results of the GC–O and OAV approaches suggests that HS–SPME–GC–O could be used as a fast and simple tool to quality control of the jambolan wine aroma.

The aim of this study was to determine the potential of red wine production from the Kosetevek grape variety (Vitis Vinifera L.) cultivated in Elazig province of Turkey and to define the characteristics of Kosetevek wines. To determine the grapes for wine production quality, the general composition, phenolic compounds, aroma compounds and sensory analysis of the wines were carried out. Aroma compounds were performed by solid-phase extraction (SPE) and then analyzed by gas chromatography (GC) along with gas chromatography/mass spectrometry (GC/MS). Results showed that the red wines obtained from Kosetevek grapes consisted of 50 aroma compounds for 2014 vintages and 49 aroma compounds for 2015 vintages. Esters were the main components contributing to the Kosetevek wine aroma along with ethyl hydrogen succinate and ethyl–4–hydroxy butanoate. The amount of total phenolic compounds, total anthocyanin, and the tannin in Kosetevek wines were found to be between 3705.45 and 3015.63 mg/L, 554.25–502.35 mg/L, and 4.5–3.95 g/L at 2014–2015 vintages, respectively. As to sensory evaluation, Kosetevek wines were characterized as a deep purple color, middle to high body, and rich in red fruit (cherries, plums), and dried fruit odors. This study has provided enological properties and aroma characterization of Kosetevek wines. The results of the study showed that Kosetevek wines could be considered as an alternative to other wines obtained from native grape varieties of the region.

PurposeThe purpose of this paper is to identify and analyse the fermentative properties of a strain of indigenousWickerhamomyces anomalus(W. anomalus) fromRosa roxburghiiTratt (R. roxburghii).Design/methodology/approachMorphological and molecular methods were used to determine the species of the selected strainW. anomalusC11. The physiological tolerances to glucose, ethanol, citric acid and sulphur dioxide (SO2) were further assessed by checking the growth of cells, and the oenological performances were proved to measure the related fermentative properties ofR. roxburghiiwines.FindingsTheW. anomalusC11 strain could be grown faster than commercialS. cerevisiaeX16 in its logarithmic growth period and had preferable tolerances to glucose, ethanol, citric acid and SO2. Moreover, this strain of nativeR. roxburghiiyeastW. anomalusC11 produced less sulphuretted hydrogen and had a higherβ-glucosidase activity. Furthermore,W. anomalusC11 could reduce the volatile acids, reduce the sourness and enhance volatile aroma richness and complexity ofR. roxburghiiwines including types of aroma and content thereof. Taken together, theR. roxburghiinative yeastW. anomalusC11 may have potential for use inR. roxburghiiwinemaking.Originality/value(1) The fermentative properties of a strain of indigenousW. anomalus(named as C11) fromR. roxburghiiwas evaluated. (2) The strain ofW. anomalusC11 had preferable tolerances to glucose, ethanol, citric acid and SO2. (3) This strain of nativeR. roxburghiiyeastW. anomalusC11 produced less sulphuretted hydrogen and had a higherß-glucosidase activity. (4)W. anomalusC11 could reduce the volatile acids, reduce the sourness and enhance volatile aroma richness and complexity ofR. roxburghiiwines including types of aroma and content thereof.

Pinot blanc is a leading grapevine variety in South Tyrol (Italy) for wine production. The high quality of its wines derives from a typical aroma of elegant apple notes and lively acidity. The typicity of the final wine depends on the origin of the vine, the soil, the oenological practices and time of harvest. The South Tyrolean mountainous areas meet the cold climatic requirements of Pinot blanc, which guarantee its sweet-acidic harmony obtained when organic acids are in balance with the other components of the wine. However, increasing temperatures in valley sites during the berry development period boost the activity of malic acid (MA) enzymes, which negatively affect the final sugar/acid ratio. Researchers are currently focused on understanding acid dynamics in wines, and there are no references for the best sugar/acid ratio for Pinot blanc. Moreover, the contribution of individual acids to the sensory profile of this wine has not yet been studied. In this study we address the effect of different climate conditions and site elevations on the sugar/acid ratio in developmental grapevine berries, and we evaluate the effect on wine bouquet. Even if different models and indices have been proposed for predicting sugar content, no predictive models exist for MA in white grapes. In a three-year study (2017, 2018 and 2019) that involved eight vineyards in four different location in South Tyrol at various elevations ranging from 223 to 730 m a.s.l., the relationships between bioclimatic indices, such as growing-degree day (GDD) and grapevine sugar ripeness (GSR) and grapevine berry content were investigated. The analysis reveals that GDD may potentially predict MA dynamics in Pinot blanc; hence, a GDD-based model was used to determine the GDD to reach target MA concentrations (3.5, 3.0, 2.5, 2.0 g/L). This simple model was improved with additional temperature-based parameters by feature selection, and the best three advanced models were selected and evaluated by 5-fold cross-validation. These models could be used to support location and harvest date choice to produce high-quality Pinot blanc wines.

This quantitative wine aroma educational study was conducted to evaluate whether hospitality student participants (N = 154) had enhanced engagement levels and interest in learning more about wine w...

Background The importance of monoterpenes in grape and wine aroma has compelled researchers to focus on developing methods to increase their abundance. Recent research has revealed that exogenous elicitors can increase the contents of these compounds. This study determined the effects of methyl jasmonate (MeJA) preharvest treatments on the monoterpene profiles of Muscat Hamburg grapes and wine. Results A total of 27 monoterpenes were identified for Muscat Hamburg grapes and wine. The contents of most of the monoterpenes (free and glycosylated forms) in the grapes and wine increased in response to MeJA. An analysis of the expression of the genes in the terpenoid biosynthesis pathway indicated that the related biosynthetic pathways were activated by MeJA. The transcript levels of some genes were consistent with monoterpene production, including VviCSLinNer, VviGwbOciF, VviPNRLin, VviGT14 and VviUGT85A1L1. The developmental expression patterns of the VviPP2B1 and VviMYB24 transcription factor genes were positively correlated with monoterpene accumulation in ripening grapes. Conclusions Our results suggest that MeJA may be useful for improving the aroma quality of grapes and wines.

The human nose has been used as a detector in gas chromatography analysis to evaluate odoriferous compounds related to aroma and quality of wine. Several olfactometric techniques are available to access the description, intensity, and/or duration of the odor of each compound. Olfactometry can be associated with one-dimensional gas chromatography or multidimensional gas chromatography, including heart-cut gas chromatography and comprehensive two-dimensional gas chromatography. Multidimensional gas chromatography may help to resolve coeluted compounds and detect important trace components for the aroma. The identification of odor-active compounds may help to differentiate wines according to terroir, grapes cultivars used in winemaking or types of aging, understand the role of fungal infection of grapes for wine quality, find the best management practices in vineyard and vinification to obtain the greatest quality. In addition, when the instrumental techniques are combined with sensory analysis, even more accurate information may be obtained regarding the overall wine aroma. This review discloses the state of the art of olfactometric methods and the analytical techniques used to investigate odor-active compounds such as one-dimensional gas chromatography, multidimensional gas chromatography, and comprehensive two-dimensional gas chromatography. The advances in knowledge of wine aroma achieved with the use of these techniques in the target and profiling approaches were also discussed.

International audience; Varietal thiols are important wine aroma compounds that are generally less abundant in red wines. Accentuated cut edges (ACE), known for accelerating phenolic extraction, was applied to Shiraz winemaking and compared with conventional crushing (NOACE) to examine the effects on varietal thiol precursor extraction and thiol formation. Water addition to grape must and skin contact time (SCT) during fermentation were also assessed. Although there was no difference for precursors in the must, ACE significantly decreased 3-S-glutathionylhexan1-ol concentration during fermentation. 3-Sulfanylhexan-1-ol and ethyl esters were significantly influenced by crushing method and/or SCT, with NOACE or shorter SCT yielding higher concentrations. Acetates, higher alcohols, fatty acids, and isoprenoids differed according to the interaction of crushing method and SCT, with ACE and shorter SCT significantly enhancing all groups except acetates. Volatiles in Sauvignon blanc and Pinot noir wines produced at commercial scale with ACE were briefly evaluated, suggesting an impact of grape variety.

Lachancea thermotolerans is a frequent yeast in the indigenous microbiota of grapes. Its main ability is the metabolization of sugars into lactic acid by using the lactate dehydrogenase enzyme, naturally decreasing wine pH during fermentation and improving wine freshness. The acidity improvement can range between 0.1 and 0.5 pH units in relation to lactic acid productions of 1–7 g/L. Additionally, the sugar metabolization into lactic acid instead of ethanol results in a slight reduction of the alcoholic degree (0.2%–0.5% vol). Most of the strains have a medium fermentative power, which generally reaches up to 10% vol; however, some strains can exceed this value. The resistance to SO2 is quite good, with many strains able to ferment at concentrations of 40–60 mg/L. The production of volatile acidity is low and frequently lower than 0.4 g/L. Some effects on wine aroma can be observed by the production of fermentative esters. L. thermotolerans is a powerful biotool to improve wine acidity and freshness, which is currently a hot topic in the enology of wine areas affected by global warming.

This chapter deals with the odorants naturally contained in wine responsible for its specific aroma nuances and for a large fraction of its flavor. First, some basic concepts related to the global sensory perception and to the outstanding role played by olfaction will be summarized. Second, the limitations of the Odor Activity Value (OAV) concept to interpret the role played by aroma chemicals in the overall perception will also be addressed. Following, the two major concepts used to understand wine aroma, the wine buffer and the aroma vectors, are defined and their properties discussed. The 35 aroma vectors forming the core of the wine aroma perception are classified into 10 sensory categories and are further described, summarizing the present knowledge about the roles played in the sensory notes of different wines. Finally, the different perceptual integration processes which form the aroma vectors leading to the final sensory perception are discussed., Funding from the Spanish MINECO (projects AGL2017-59840 and RTC-2016-4935) and from European Union’s Horizon 2020 grant agreement No 643063. M.P.S.N. acknowledges the MINECO for her postdoctoral fellowship (Juan de la Cierva Incorporación 2015). LAAE acknowledges the continuous support of Diputación General de Aragón (T29) and European Social Fund. All the former LAAE members whose work has been essential to this chapter are gratefully acknowledged.

This study aimed to investigate the key compounds involved in the aroma of French Syrah wines from the northern Rhone valley from two vintages characterized by distinct climatic conditions. The volatile composition of the wines was assessed through the determination of 76 molecules. After identifying the best matrix and best model for aroma reconstitution studies, omission tests were conducted using the Pivot© profile method. For both vintages, 35 molecules with odor activity values (OAVs) above 0.5 were identified. While remarkably high levels of 2-furfurylthiol (FFT) were reported in both wines, rotundone and 3-sulfanylhexanol (3SH) enabled the strongest discrimination between the two wines. Wine dearomatized using supercritical carbon dioxide (sCO2) was identified as the best matrix. The best models built using this matrix were composed of molecules with OAV > 5 and OAV > 10 highlighting that this dearomatization approach can be valuable to reconstitute the aroma of wine using a small number of molecules. For the cool vintage wine, the omission of rotundone and FFT had the greatest impact on the olfactive profile for non-anosmic and anosmic respondents to rotundone, respectively. 3SH, whose omission decreased the rating of the ‘fruity’ attribute, was identified as the main contributor to the aroma of Syrah wine produced in the warm vintage.

Low-temperature red winemaking is mainly used for enhancing the wine aroma; however, colour and phenolic extraction is reduced under this condition. This work evaluated the effects of the pectinoly...

Vitis vinifera L. Pinot noir still wines are some of the most popular and expensive red wines in the world. Several research articles are reported in literature concerning the impacts of viticultural and enological practices, and vineyard location, on Pinot noir still wine aroma. This review summarizes the previous and latest literature pertaining to volatile compounds including esters, higher alcohols and C13-norisoprenoids, and their effect on Pinot noir wine perceived aroma. Their origin and behavior are discussed, as well as their role in regional differentiation. The first part of this review paper presents an overview of volatile compounds that are usually found in Pinot noir still wines at concentrations higher than their odor detection threshold. The second part deals with studies pertaining to human inputs that impact on Pinot noir wine aroma profile such as viticulture and winemaking interventions. The role of the vineyard site is also revised. This review concludes by considering what further opportunities are available to researchers in this field for greater control over Pinot noir wine quality outcomes.

The quality of red wine is dependent on the presence not only of volatile compounds that influence wine aroma but also on phenolic compounds due to their impact on mouthfeel, colour, flavour and ageing potential. Whereas wine aroma arises from the grapes, action of microorganisms and maturation phenomena, red wine phenolics are predominantly found in the grape berry skins and seeds and are extracted during maceration into the fermenting must (i.e. grape solids and juice). Thus, although every step in winemaking has a significant impact on the outcome of the finished product, it can be considered that fermentation and the ensuing extraction of grape components are the most critical value adding step in the process. This mini-review examines such aspects, and against this backdrop, considers the need for improvements to fermentation control during wine production, to optimise the outcome of extraction from grape solids. Specifically, there is interest in modulating and forecasting wine composition based on grape specifications, and with this, the ability to regulate winery production practices to achieve target quality specifications. Such predictions and measures are proposed to help winemakers adapt to emerging issues associated with climate change. KEY POINTS: • Definition and description of important grape metabolites extracted during winemaking. • Description of processes influencing development and extraction of grape components. • Includes key aspects related to vineyard, harvesting, winemaking, and ageing. • Covers future trends regarding extrac Mini-Reviewtion, climate change and production efficiency.

Aim: This work evaluates the effects of the combined use of heat treatment (HT, 75 °C, 2 min) and proteases (P) on the protein stability and volatile composition of two white wines, obtained from the Greek cv. Assyrtiko and Moschofilero.Methods and results: Wine protein stabilization was assessed by heat test, using RP-HPLC determination of pathogenesis-related proteins (PRP) and by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The impact of bentonite and P + HT treatment on wine aroma profile was evaluated by GC-MS with liquid–liquid extraction. According to the heat test, in Assyrtiko wine the level of stability achieved with P + HT was comparable with that obtained by bentonite fining and for Moschofilero wine – where protein instability was higher – bentonite was more efficient. RP-HPLC profiles showed that, in general, higher percentages of chitinases (CH) than thaumatin-like proteins (TLP) were removed by both bentonite and P + HT, with a similar efficiency for the two treatments and sometimes better performances for the latter. Conversely, TLP were removed more efficiently by bentonite, even if some fractions were eliminated to a slightly higher extent by proteases. In the conditions of the experiment, bentonite resulted in minor changes to the wine aroma profile. However, heating during protease treatment modified wine volatile composition, reducing the concentration of esters produced during fermentation while simultaneously increasing the contents of certain esters characteristic of aging such as ethyl lactate.Conclusions: The combination of proteases and heat treatment may be a promising technique for protein stabilization of wines. However, further investigations are needed to optimize the time:temperature ratio of the heat treatment in order to obtain the maximum protease activity and the minimum thermal deterioration of the wine quality.Significance and impact of the study: The results of this study have a practical interest for both the scientific community and wine sector, contributing to knowledge of the efficacy and limitations of the use of protease enzymes for wine stabilization.

Montepulciano d'Abruzzo is a red wine grape variety of Vitis vinifera L., grown in Central Italy. It is mainly identified with Abruzzo region, where it currently accounts for around 50% of the regional vineyard. Malolactic fermentation (MLF) has a crucial role in red wines giving microbial stabilization, biological deacidification through the decarboxylation of l-malic acid to l( +)-lactic acid and carbon dioxide, and increasing complexity of wine aroma. Studies are focusing on the selection of yeast starter cultures for this wine, while few studies are available on malolactic bacteria. Therefore, a technological (ability to grow up at different pH, concentration of SO2, ethanol, presence of hdc, tdc and odc genes, conversion of malic acid into lactic acid) and genetic characterization of autochthonous Oenococcus oeni strains was performed. Moreover, O. oeni strain with the best traits was selected and produced by a local starter industry and used in cellar to produce Montepulciano d’Abruzzo organic wine without added SO2. Obtained wines not only maintained the typical traits of Montepulciano d’Abruzzo wines but also showed healthy characteristics since wines were histamine free. Selected starter is actually produced and dispensed on demand and in a frozen concentrate culture for wineries.

Background and Aims Wines aged in wood barrels are likely to contain Brettanomyces yeasts, which are able to produce off‐flavour compounds such as ethylphenols and vinylphenols. In this work, both off‐flavoured and pleasant phenol compounds were quantified in Portuguese wines with an improved analytical technology. Methods and Results A novel one‐step dispersive liquid–liquid microextraction method with simultaneous derivatisation followed by fast low‐pressure GC/MS was optimised and applied to 49 red wine samples of commercial and private origin. The analytical performance demonstrated the ability of the proposed method to accurately measure all the analytes under study. Conclusions Ethyl and vinylphenols were present in most of the wines, at a concentration frequently higher than their preference threshold, and thus high enough to affect the overall aroma of the wine. Home‐made wines had a higher concentration of off‐flavour compounds in contrast with that of commercial wines, which had a high concentration of pleasant flavour compounds. Statistical analysis showed that less expensive wines exhibited a significantly lower concentration of syringol, and there was a tendency for the concentration of vinylphenols and ethylphenols to increase throughout wine aging. Significance of the Study The presence of off‐flavour phenols is a major concern of the wine industry, requiring great attention during the different stages of the winemaking process, so that wine aroma is not negatively affected.

Nowadays, consumers demand honey peach wines with a certain amount of bioactive ingredients, typical color, soft tannins, and fruit scents, but these wines can only be obtained from honey peaches with the optimal maturity. The goal of this study was to determine the differences between quality indexes and aroma characteristics of honey peach wines produced from different mature fruits. Honey peaches at harvest were divided according to maturity into four groups to investigate the physicochemical properties, bioactive ingredients, color, transmittance, volatile flavor component, and sensory acceptability of four groups of wine samples. The results showed that the higher the maturity of the honey peaches, the higher the color intensity, tannin content, and ester content, the lower the total phenolic content (TPC), total flavonoid contents (TFC), and transmittance of wines. When the maturity of honey peaches increased, the balance between the flavor and mouthfeel sensation was improved, whereas the unpleasant taste of wine occurred because of some spoilage acid produced by excessive-ripened honey peaches. In conclusion, the optimal harvest period of honey peaches to produce honey peach wines was between 90% and100% maturity stage. These results suggest that honey peaches maturity may influence the final wine composition and quality, and should be considered at harvest.

Fungal diseases in vineyards are one of the main causes leading to economic losses within the viticulture sector and are continuously increasing with time. The most common of these fungal diseases are powdery mildew, downy mildew and grey mould which are controlled by the use of fungicides. However, fungicide residues can alter the fermentation process and prevent some biochemical pathways of yeast metabolism involved in phenolic and/or aroma compound production that are critical for sensory quality. In this study, Chenin blanc grapes treated with chemical and natural fungicides were used to produce small-scale wines and laboratory-scale fermentations. Treatments consisted of a control (an approved chemical used in industry), a 1x and 2x treatment (new formulations). Laboratory-scale fermentations were conducted in duplicate using the commercial Saccharomyces cerevisiae (S. cerevisiae) Active Dry Wine Yeast (ADWY) strains VIN 13 and VIN 7. The fermentations were monitored by weighing frequently until they stabilised (CO2 weight loss). Small-scale wines were made according to the standard Nietvoorbij experimental wine making procedure. At the end of fermentation, lees samples were subjected to CHEF gel electrophoreses to confirm that the inoculated yeast strain completed the fermentations. Moreover, fermenting wine samples, collected at the start and end of the fermentation, were subjected to protein extraction, quantification and characterisation the yeast proteins expressed at the various stages of fermentation. Resultant wines were subject to chemical and sensory evaluations five months after bottling. From the results obtained in the above study, it was concluded that the inoculated yeast strains used for wine making completed the fermentations at a similar rate to their respective controls (registered fungicide). In addition, small-scale cellar fermentations showed that the fungicide treatments (1x the recommended dosage [Treatment 1] and 2x the recommended dosage [Treatment 2]) compared to the controls had no notable negative effects on wine aroma and sensory profiles although differences were observed in the proteins expressed after the fermentation. The chemical and biological fungicides had no notable effects on the wine making procedure and quality of resulting wines compared to the registered fungicide.

Sauvignon blanc grape samples (n = 21) from across a single Geographical Indication of South Australia were analysed for thiol precursors and amino acids, and fermented in an identical laboratory-scale fermentation trial to investigate the intraregional pattern of varietal thiols in the wines. Precursors and thiols exhibited obvious intraregional diversity, and notably, stronger correlations were observed between a number of amino acids and thiol precursors (especially with glutamic acid, r ≤ −0.73) rather than free thiols. Additionally, pre-fermentation freezing (−20 °C, 1 month) was applied to five selected fresh grape samples and their juices, followed by identical fermentation. In comparison to wines from fresh grapes or frozen juices, significant elevation of varietal thiols (up to 10-fold) occurred in the wines derived from frozen grapes, with parallel increases of precursors (up to 19-fold) in juices from frozen berries. These novel results may lead to new strategies for thiol enhancement during winemaking.

Non-Saccharomyces yeast plays an important role in the initial stages of a wild ferment, as they are found in higher abundance in the vineyard than Saccharomyces cerevisiae. As such, there has been a focus in recent years to isolate these yeast species and characterize their effect on wine fermentation and subsequent aroma. This effect on wine aroma is often species and strain dependent, as the enzymatic profile of each yeast will determine which aroma compounds are formed as secondary metabolites. Semi-fermentative yeast, such as Hanseniaspora spp., Candida spp. and Metschnikowia pulcherrima, are commonly in high abundance in fresh grape must and have diverse enzymatic profiles, however they show a weak tolerance to ethanol, limiting their impact to the initial stages of fermentation. Fully fermentative non-Saccharomyces yeast, characterized by high ethanol tolerance, are often found at low abundance in fresh grape must, similar to Saccharomyces cerevisiae. Their ability to influence the aroma profile of wine remains high, however, due to their presence into the final stages of fermentation. Some fermentative yeasts also have unique oenological properties, such as Lanchancea thermotolerans and Schizosaccharomyces pombe, highlighting the potential of these yeast as inoculants for specific wine styles.

Wine reflects the specificity of a terroir, including the native microbiota. In contrast to the use of Saccharomyces cerevisiae commercial starters, a way to maintain wines’ microbial terroir identities, guaranteeing at the same time the predictability and reproducibility of the wines, is the selection of autochthonous Saccharomyces and non-Saccharomyces strains towards optimal enological characteristics for the chosen area of isolation. This field has been explored but there is a lack of a compendium covering the main methods to use. Autochthonous wine yeasts from different areas of Slovakia were identified and tested, in the form of colonies grown either on nutrient agar plates or in grape must micro-fermentations, for technological and qualitative enological characteristics. Based on the combined results, Saccharomyces cerevisiae PDA W 10, Lachancea thermotolerans 5-1-1 and Metschnikowia pulcherrima 125/14 were selected as potential wine starters. This paper, as a mixture of experimental and review contributions, provides a compendium of methods used to select autochthonous wine yeasts. Thanks to the presence of images, this compendium could guide other researchers in screening their own yeast strains for wine production.

Made available in DSpace on 2022-05-01T09:47:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-11-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) β-Glucosidases have been extensively investigated to integrate the enzyme complex for cellulose fiber saccharification and for improving the aroma of wine. To produce these enzymes, greater attention has been given to filamentous fungi and bacteria, and few investigations have targeted the potential applications of enzymes secreted by yeasts. Addressing this issue, in this study, β-glucosidases were produced by the Pichia ofunaensis and Trichosporon multisporum yeasts, via solid state fermentation with wheat bran as a substrate. When using p-Nitrophenyl β-d-glucopyranoside (pNPG) as an enzyme substrate, maximum β-glucosidase activities were detected at pH 5.5–6.0 and 50–60 °C for P. ofunaensis, and pH 5–6 and 55 °C for T. multisporum. Both enzymes were able to hydrolyze cellobiose and exhibited stability over a wide range of pH (3.5–9.0) for 24 h at 4 °C, thermostability up to 50 °C for 1 h and tolerance to 10 mM phenolic compounds. Negative modulation on enzyme activity was observed in the presence of Cu2+, Fe3+, Zn2+, Al3+ and Hg2+, while both β-glucosidases were tolerant to 30% methanol, isopropanol and acetone. In the presence of ethanol and glucose, enzymes from P. ofunaensis were the more active and stable of the two. These enzymes, especially the P. ofunaensis β-glucosidases, could be tested in enology for improving the aroma of wine and for integrating a cellulolytic complex to produce 2G ethanol. Instituto de Biociências Letras e Ciências Exatas Universidade Estadual Paulista “Júlio de Mesquita Filho”, R/Cristóvão Colombo, 2265, Jd Nazareth, Ibilce-Unesp Instituto de Biociências Letras e Ciências Exatas Universidade Estadual Paulista “Júlio de Mesquita Filho”, R/Cristóvão Colombo, 2265, Jd Nazareth, Ibilce-Unesp FAPESP: 2017/06066-4 FAPESP: 2017/06399-3 FAPESP: 2018/07036-4

The aim of this work was to enhance the levels of fruity esters in spine grape (Vitis davidii Foёx) wine by goal-directed amino acid supplementation during fermentation. HPLC and GC-MS monitored the amino acids and fruity esters, respectively, during alcoholic fermentation of spine grape and Cabernet Sauvignon grape. HPLC was also used to determine the extracellular metabolites and precursors involved in the synthesis of fruity esters. Alanine, phenylalanine, and isoleucine levels in spine grape were less than those in Cabernet Sauvignon. Pearson correlation between amino acid profile and fruity ester content in the two systems indicated that deficiencies in alanine, phenylalanine, and isoleucine levels might have limited fruity ester production in spine grape wine. Supplementation of these three amino acids based on their levels in Cabernet Sauvignon significantly increased fruity ester content in spine grape wine. Interestingly, goal-directed amino acid supplementation might have led to changes in the distribution of carbon fluxes, which contributed to the increase in fruity ester production.

In this study, nineOenococcus oenistrains were tested for their ability to adhere to polystyrene using mMRS and wine as culture media. Moreover, planktonic and biofilm-detached cells were investigated for their influence on malic acid degradation kinetics and aroma compound production. Three strains were able to adhere on polystyrene plates in a strain-dependent way. In particular, MALOBACT-T1 and ISO359 strains mainly grew as planktonic cells, while the ISO360 strain was found prevalent in sessile state. The strain-dependent adhesion ability was confirmed by confocal laser scanning microscopy. Planktonic and biofilm detached cells showed a different metabolism. In fact, biofilm-detached cells had a better malic acid degradation kinetic and influenced the aroma composition of resulting wines, acting on the final concentration of esters, higher alcohols, and organic acids.Oenococcus oeniin biofilm lifestyle seems to be a suitable tool to improve malolactic fermentation outcome, and to contribute to wine aroma. The industrial-scale application of this strategy should be implemented to develop novel wine styles.

Wine aroma is an important quality trait in wine, influenced by its volatile compounds. Many factors can affect the composition and levels (concentration) of volatile aromatic compounds, including the water status of grapevines, canopy management, and the effects of climate change, such as increases in ambient temperature and drought. In this study, a low-cost and portable electronic nose (e-nose) was used to assess wines produced from grapevines exposed to different levels of smoke contamination. Readings from the e-nose were then used as inputs to develop two machine learning models based on artificial neural networks. Results showed that regression Model 1 displayed high accuracy in predicting the levels of volatile aromatic compounds in wine (R = 0.99). On the other hand, Model 2 also had high accuracy in predicting smoke aroma intensity from sensory evaluation (R = 0.97). Descriptive sensory analysis showed high levels of smoke taint aromas in the high-density smoke-exposed wine sample (HS), followed by the high-density smoke exposure with in-canopy misting treatment (HSM). Principal component analysis further showed that the HS treatment was associated with smoke aroma intensity, while results from the matrix showed significant negative correlations (p &lt, 0.05) were observed between ammonia gas (sensor MQ137) and the volatile aromatic compounds octanoic acid, ethyl ester (r = −0.93), decanoic acid, ethyl ester (r = −0.94), and octanoic acid, 3-methylbutyl ester (r = −0.89). The two models developed in this study may offer winemakers a rapid, cost-effective, and non-destructive tool for assessing levels of volatile aromatic compounds and the aroma qualities of wine for decision making.

Hanseniaspora species are the main yeasts isolated from grapes and grape musts. Regarding genetic and phenotypical characterization, especially fermentative behavior, they can be classified in two technological clusters: the fruit group and the fermentation group. Among the species belonging to the last group, Hanseniaspora osmophila and Hanseniaspora vineae have been previously isolated in spontaneous fermentations of grape must. In this work, the oenological aptitudes of the two species of the fermentation group were compared with Saccharomyces cerevisiae and the main species of the fruit group, Hanseniaspora uvarum. Both H. osmophila and H. vineae conferred a positive aroma to final wines and no sensory defects were detected. Wines fermented with H. vineae presented significantly higher concentrations of 2-phenylethyl, tryptophol and tyrosol acetates, acetoin, mevalonolactone, and benzyl alcohol compared to H. osmophila. Sensorial analysis showed increased intensity of fruity and flowery notes in wines vinificated with H. vineae. In an evolutionary context, the detoxification of alcohols through a highly acetylation capacity might explain an adaption to fermentative environments. It was concluded that, although H. vineae show close alcohol fermentation adaptations to H. osmophila, the increased activation of phenylpropanoid metabolic pathway is a particular characteristic of H. vineae within this important apiculate genus.

With increases in climate extremes resulting in more abiotic and biotic stress on crops such as grapes, it is essential to develop new cultivars that are more robust than the traditional Vitis vinifera but, with the flavor attributes consumers' desire. The interspecific hybrid cultivars developed from crossing V. vinifera with the wild Vitis species do possess cold hardiness and disease resistance, however, the aroma profile of these hybrids are generally less popular in comparison to the V. vinifera grapes. Developing an understanding of the aroma profile of the hybrid grapes is essential to understand how they differ from vinifera cultivars and how viticultural management practices impact their aroma composition. While earlier efforts have been made to determine the volatile profile of hybrid grapes and wines using targeted analysis, we opted for the more inclusive non-targeted metabolomics approach to investigate their differences. The objective of this dissertation is to investigate the aroma profile of two hybrid grapes Norton and Chambourcin, important to the Mid-Western United states, including Missouri, along with the differences during berry development. We also investigated the change in aroma profile of Chambourcin berries due to various viticulture operations, rootstocks, and irrigation using a metabolomics-based approach. To understand consumer preference, differences in aroma between vinifera and interspecific hybrid grapes and wines need to be investigated so that the concentration of the key volatiles can be adjusted by various viticultural and enological practices to make better wine as well as develop cultivars that fit consumer preference better. In Chapter 2, we investigated berry and wine volatile differences between Norton, a popular interspecific hybrid cultivar in Missouri, and Cabernet Sauvignon, a popular Vitis vinifera cultivar known for its wine quality and cultivated worldwide. Berries were sourced from different locations, vintages, and ripening whereas, wines analyzed were commercial wines from different vintages and locations. The volatiles was analyzed using HS-SPME-GCMS and then processed using XCMS online to identify 924, 793, and 1064 metabolic features (M(m/z) T (retention time in minutes)). Multivariate analysis of the significant features (p-value [less than] 0.05 and fold change [greater than] 1.5) demonstrated that the genome of the cultivar is the strongest factor driving differences in free, total and wine volatiles even though there is much variability in the environmental, year, viticultural factors in the berries and wine sampled. Many compounds were identified to be different between two cultivars and some related to plant defense including methyl salicylate and eugenol were found in higher concentrations in Norton. The identified compounds were used as markers to phenotype the F1 population derived from Norton and Cabernet Sauvignon cross. The F1 population demonstrated segregation for the identified compounds with some genotypes demonstrating higher or lower concentrations for the compounds. The future work is to map these volatile compounds using a genetic map to identify regions in genomes that are regulating them, which will accelerate the breeding of cultivars with desired traits from both cultivars. Besides genetics, many viticultural factors such as irrigation management, rootstocks, sun exposure, and hedging have been found to play a pivotal role in manipulating the vine physiology and berry chemistry, thus impacting wine quality. We investigated the impact of rootstocks and irrigation treatments in berry and wine quality using an experimental vineyard planted with Chambourcin own-rooted as well as grafted to three commercial rootstocks (1103P, 3309C, SO4) subjected to three irrigation regimes (full, RDI and none) in a complex experimental design. Since there is no published study on the volatile profile of Chambourcin grapes and wines, and since there is no predefined information on the volatiles that are important in this cultivar, we used a metabolomics-based approach to extract as much information as possible. Chapter 3 of the dissertation aims to study the wine volatiles as impacted by rootstocks and irrigation in a comprehensive and unbiased way. Based on the multivariate analysis, rootstocks had the greatest influence on wine volatiles, but the assortment of compounds was modulated by the season and the irrigation regime. Own-rooted Chambourcin was found to differ from other root-systems for multiple volatile compounds such as Linalool, Ethyl Nonanoate, [beta]-Damascenone, and TDN, whereas fewer differences were detected among grafted vines. Rootstocks were found to increase concentrations of compounds such as Linalool, while, [beta]-Damascenone was found to be highest in own-rooted Chambourcin wines. Significant differences among irrigation regimes were also observed along with the interaction between rootstock and irrigation. [Beta]-Damascenone was higher in RDI than in other treatments. Finding significant differences in wine volatiles due to rootstocks and irrigation, we then investigated the berry volatiles during the course of its development also using the metabolomics-based approach. Volatile compounds present in grapes, as well as aroma precursors, are crucial for wine quality, with their concentrations impacted by a complex interplay between the natural environment (soil conditions, climate, temperature), vineyard management practices (irrigation, pruning, sun exposure) and vine genotypes, including the genomes of both the scion and the rootstocks. Grape-derived volatiles can be free volatiles that are present in grapes as well as aroma precursors which are present as glycosides in grapes and later released during the winemaking processes. Both free and bound volatiles are found to differ during berry development. We investigated the impact that rootstocks and irrigation have on free and total (free + glycosidase releasable) volatiles using the same Chambourcin experiment as described above. Phenology (ripening state) and year were found to be the most significant factors to impact berry volatiles, with berries being more similar in volatile composition at veraison than at harvest, confirming the commonly held view that secondary metabolism in berries reflects the various stresses the vine experiences during the growing season. Rootstocks and irrigation both had a subtle but significant impact on many free and total berry volatiles. Rootstocks were found to be a significant factor impacting free and total volatiles, differentiating own-rooted from grafted vines as well as differentiating between different rootstocks. The fact that rootstocks had only subtle effects on berry volatiles but a major impact on the relative concentration of wine volatiles raises the possibility that the principal manner by which rootstocks modulate wine volatiles may not be the concentration of berry metabolites. It is possible that other factors, such as grape-derived enzymes that modify or release volatile compounds during fermentation, are the ones through which rootstocks primarily influence wine quality. In the final chapter, the basic berry chemistry traits, organic acids, vine yield, and vine midday stem water potential as impacted by rootstocks and irrigation were investigated. Basic berry chemistry and organic acids significantly impact the flavor of the grapes and wines as well as the extraction of many volatiles from berries to wine. The future work is to investigate the relationship between berry and wine volatiles to understand the predictability of wine quality. Also, correlating berry and wine volatiles with many other phenotypes that were collected concurrently as part of the bigger project will be performed. These include remote sensing, hyperspectral data, gene expression, leaf ionomics, leaf morphometrics, epigenetic regulation, and root microbiome that will unfold interesting details about the impact that each of those traits has on berry and wine quality.

The use of non-Saccharomyces yeasts in sequential fermentations with S. cerevisiae has been proposed to improve the organoleptic characteristics involved in the quality of wine. The present study set out to select a non-Saccharomyces inoculum from the D.O.Ca. Rioja for use in winemaking. Strains included in the study belonged to Torulaspora delbrueckii, Lachancea thermotolerans, Metschnikowia pulcherrima, Zygosaccharomyces bailii, Williopsis pratensis, Debaryomyces hansenii, Pichia kluyveri, Sporidiobolus salmonicolor, Candida spp., Cryptococcus spp. and two mixed inocula of Lachancea thermotolerans-Torulaspora delbrueckii in a 30/70 ratio. In the first stage of the process, SO resistance and presence of enzymatic activities related to wine aroma and wine color and fining (esterase, esterase-lipase, lipase, leucine arylamidase, valine arylamidase, cystine arylamidase, β-glucosidase, pectinase, cellulose, xylanase and glucanase) were studied. In the later stages, selection criteria such as fermentative behavior, aroma compound production or influence on phenolic compounds were studied in laboratory scale vinifications. Taking into account the results obtained in the different stages of the process, a mixed inoculum of Lachancea thermotolerans-Torulaspora delbrueckii in a 30/70 ratio was finally selected. This inoculum stood out for its high implantation capacity, the production of compounds of interest such as glycerol and lactic acid and the consequent modulation of wine acidity. Given these characteristics, the selected inoculum is suitable for the production of quality wines., This research was funded by Instituto Nacional de Investigaciones Agrarias (INIA) (Project RTA2013-0053-C03).

In grapes, monoterpenes and norisoprenoids are in the form of non-volatile compounds, flavourless glycosides which could enhance the aroma of wines after its hydrolysis using β- glucosidases enzymes. It is known that the use of immobilised enzymes offers advantages such as reusability and easy recuperation. In this study, a commercial β-glucosidase was immobilised by absorption in sodium alginate. Biotechnological characteristics and terpen hydrolysis (hydrolysis aroma precursors) in muscat wines were studied after treatment with both free and immobilised commercial β- glucosidase with two different concentrations. It was revealed that both forms shared an optimal pH (4.5) and a maximum temperature (64°C), even an increment on the activity between 40and 60°C. A similar Km value has been determined while Vmax from the immobilised enzyme was higher than the free (3.35 and 2.52 μmol min–1 mg–1, respectively). Additionally, the immobilised enzyme showed a better hydrolytic activity during 24 h, and its reusability has been proven. Regarding enzymatic hydrolysis in grape must, the best results were observed for the highest concentration of free β-glucosidase although glucose release was also determined for the immobilised enzyme along the days. In contrast, maximum activity was reached by the immobilised β-glucosidase in less time but in no case equalled the free ones. Finally, volatile compound liberation in wines treated with free or immobilised enzymes was analysed using HRGC-MS. Liberation for both enzymes and the greatest concentrations of some volatiles were detected when a double dose of the free β-glucosidase was used. Nevertheless, the wines treated with the immobilised β-glucosidase showed a high concentration of some volatile compounds such as nerol or geraniol.

Elemental sulphur is a common fungicide applied in vineyards before harvest, and has been found toincrease the production of desirable polyfunctional mercaptans, but also H2S and unwanted reductivesulphur aroma compounds. This paper investigates the effectiveness of oxygen and nitrogen sparging,applied during fermentation, on the removal of volatile sulphur compounds in Sauvignon blanc wines.Increasing the amount of elemental sulphur added to grapes after pressing, from nil to 10 to 100 mg/L,led to an increase in the formation of 3-mercaptohexanol (3MH), of 3-mercaptohexyl acetate (3MHA) forthe 10 mg/L additions only, and of some unwanted reductive compounds. Few changes were observed inthe concentrations of aroma compounds when the juices were sparged with nitrogen during fermentation.Additions of oxygen during fermentation led to some decrease in the concentration of polyfunctionalmercaptans for the 10 mg/L sulphur additions, but did not significantly remove reductive aroma compounds.Few differences were observed in the concentration of wine phenolics or of further wine aroma familieswith any of the treatments.

In Brazil, wine-growing regions of high altitude have been evaluated for the cultivation of grapes destined for the production of quality wines. In this study the phenolic content, the volatile compounds profile and the in vitro antioxidant activity of samples produced in Água Doce, Campos Novos and Tangará were determined using spectrophotometric and chromatographic techniques. A total of 95 volatile compounds were identified in the samples analyzed, of which borneol is reported in Brazilian Merlot wines for the first time. The quantitative results showed that the most important volatile compounds for wine aroma were esters, fatty acids, 1-hexanol and 2-phenylethanol alcohols, and C13-norisoprenoids β-damascenone and α-ionone. The phenolic content observed was comparable to the results obtained for Merlot red wines from other regions in Brazil and in other countries. Also, the wine samples were effective in capturing the free radicals DPPH and ABTS.

Although perceptual interactions are usually mentioned and blamed for the difficulties in understanding the relationship between odorant composition and aromatic sensory properties, they are poorly defined and categorised. Furthermore, old classifications refer mainly to effects on the odour intensity of the mixture of dissimilar non-blending odours and do not consider odour blending, which is one of the most relevant and influential perceptual interactions. Beginning with the results from classical studies about odour interaction, a new and simple systematic is proposed in which odour interactions are classified into four categories: competitive, cooperative, destructive and creative. The first categories are most frequent and display a mild level of interaction, being characterised mostly by analytical processing. The last two are less frequent and activate (or deactivate) configurational processes of object recognition with deep effects on the quality and intensity of the perception. These interactions can be systematically applied to interpret the formation of sensory descriptors from the odorant composition, suggesting that qualitatively the system works. However, there is a lack of quantitative data to work with odour intensities reliably, and a pressing need to systematise the effects of creative interactions., Spanish Ministry of Economy and Competitiveness (MINECO) (project AGL-2017-87373- C3-1-R). LAAE acknowledges the continuous support of Diputación General de Aragón (T29) and European Social Fund. MPSN acknowledges the Spanish National Research Agency, the Ministry of Science, Innovation, and Universities and the European Social Fund for her postdoctoral fellowship: Ramón y Cajal Program (RYC2019-027995-I/AEI/10.13039/501100011033).

The aromatic expression of wines can be enhanced by the addition of specific glycosidases, although their poor stability remains a limitation. Coimmobilization of glycosidases as cross-linked enzyme aggregates (combi-CLEAs) offers a simple solution yielding highly stable biocatalysts. Nevertheless, the small particle size of combi-CLEAs hinders their recovery, preventing their industrial application. Encapsulation of combi-CLEAs of glycosidases in alginate beads and in polyvinyl alcohol is proposed as a solution. Combi-CLEAS of β-d-glucosidase and α-l-arabinofuranosidase were prepared and encapsulated. The effects of combi-CLEA loading and particle size on the expressed specific activity (IU/gbiocatalyst) of the biocatalysts were evaluated. Best results were obtained with 2.6 mm diameter polyvinyl alcohol particles at a loading of 60 mgcombi-CLEA/gpolyvinyl alcohol, exhibiting activities of 1.9 and 1.0 IU/gbiocatalyst for β-d-glucosidase and α-l-arabinofuranosidase, respectively. Afterwards, the stability of the biocatalysts was tested in white wine. All the encapsulated biocatalysts retained full activity after 140 incubation days, outperforming both free enzymes and nonencapsulated combi-CLEAs. Nevertheless, the alginate-encapsulated biocatalysts showed a brittle consistency, making recovery unfeasible. Conversely, the polyvinyl-encapsulated biocatalyst remained intact throughout the assay. The encapsulation of combi-CLEAs in polyvinyl alcohol proved to be a simple methodology that allows their recovery and reuse to harness their full catalytic potential.

BACKGROUND: Monoterpenes and C13-norisoprenoids are key terpenoid compounds for wine aroma. The enzyme encoded by VviDXS1 participates in terpenoid biosynthesis in grapevine fruits and gain-of-function mutations in this gene lead to characteristic muscat aroma. OBJECTIVE: To assess for VviDXS1 contribution to aroma variation in Northwestern Iberian wine cultivars, we resequenced this gene in 111 cultivars and compared grape juice terpenic composition in 12 of them. METHODS: VviDXS1 was capture-targeted for resequencing with Illumina paired-end reads, SAMtools was used for variant calling and gene haplotypes were reconstructed with PHASE. Monoterpenes and C13-norisoprenoids were quantified in free and glycosidically-bound forms from grape juice by gas chromatography-mass spectrometry. RESULTS: Terpenic composition discriminated between muscat, terpenic and neutral profiles across cultivars. While the terpenic profile of Loureira and Albariño white cultivars was not associated with muscat-like mutations, Albariño carries a V34L substitution in VviDXS1 that is also present in other aromatic cultivars and was not reported before. Tempranillo and Cabernet Sauvignon red cultivars accumulated higher levels of C13-norisoprenoids, which was not associated with specific variation in VviDXS1. CONCLUSIONS: Apart from the uncharacterized substitution present in Albariño, findings suggest that terpenoid pathway-related genes other than VviDXS1 could contribute to the aromatic attributes of these cultivars., This work was partially supported by project RTA 2011-00100-C05-00, BIO2011-26229 and BIO2017-86375 by the Spanish MICINN and IN841C by the Xunta de Galicia.

A new quantitative method based on static headspace−gas chromatography−ion mobility spectrometry (SHS−GC−IMS) is proposed, which enables the simultaneous quantification of multiple aroma compounds in wine. The method was first evaluated for its stability and the necessity of using internal standards as a quality control measure. The two major hurdles in applying GC-IMS in quantification studies, namely, non-linearity and multiple ion species, were also investigated using the Boltzmann function and generalized additive model (GAM) as potential solutions. Metrics characterizing the model performance, including root mean squared error, bias, limit of detection, limit of quantification, repeatability, reproducibility, and recovery were investigated. Both non-linear fitting methods, Boltzmann function and GAM, were able to return desirable analytical outcomes with an acceptable range of error. A potential pitfall that would cause inaccurate quantification i.e., competitive ionization, is also discussed. These findings provide an initial validation of a GC-IMS-based quantification method, as well as a starting point for further enhancing the analytical scope of GC-IMS.

Lugana and Verdicchio are two Italian white wines with a Protected Designation of Origin (PDO) label. These two wine types are produced in different regions using the same grape variety. The aim of this work is to investigate the existence of volatile chemical markers that could help to elucidate differences between Lugana and Verdicchio wines both at chemical and sensory levels. Thirteen commercial wine samples were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS), and 76 volatile compounds were identified and quantified. Verdicchio and Lugana had been differentiated on the basis of 19 free and glycosidically bound compounds belonging to the chemical classes of terpenes, benzenoids, higher alcohols, C6 alcohols and norisoprenoids. Samples were assessed by means of a sorting task sensory analysis, resulting in two clusters formed. These results suggested the existence of 2 product types with specific sensory spaces that can be related, to a good extend, to Verdicchio and Lugana wines. Cluster 1 was composed of six wines, 4 of which were Lugana, while Cluster 2 was formed of 7 wines, 5 of which were Verdicchio. The first cluster was described as “fruity”, and “fresh/minty”, while the second as “fermentative” and “spicy”. An attempt was made to relate analytical and sensory data, the results showed that damascenone and the sum of 3 of esters the ethyl hexanoate, ethyl octanoate and isoamyl acetate, was characterizing Cluster 1. These results highlighted the primary importance of geographical origin to the volatile composition and perceived aroma of Lugana and Verdicchio wines.

Background and Aims Wine made from the Campbell Early grape cultivar has less flavour than wine made from European grape cultivars. The aim of this study was to investigate the individual fermentation characteristics of several non‐Saccharomyces yeasts for improving the aroma of Campbell Early wine. Methods and Results Nine species of non‐Saccharomyces yeasts were used as wine starters in single or co‐fermentation with Saccharomyces cerevisiae. Several fermentation characteristics and physiological properties were investigated. Volatile higher alcohol and ester compounds were also analysed by GC/MS and by principal component analysis. Single‐fermented wines showed different fermentation kinetics, whereas co‐fermented wines showed similar, but slightly different, fermentation kinetics depending on their ethanol tolerance. Principal component analysis indicated that the composition of both volatile higher alcohols and esters was distinguishable between single and co‐fermented wines, but volatile esters in co‐fermented wines were more widely distributed compared to that in single fermented wines. Conclusions The fermentation kinetics of each strain was different. Volatile esters were more affected by co‐fermentation than volatile higher alcohols, which were produced during the early phase of fermentation. Moreover, interactions among the various volatile aromatic compounds affected the final wine aroma. Significance of the Study These findings could provide valuable information to researchers and winemakers on the enhancement of wine aroma using non‐Saccharomyces yeasts.

Non-Saccharomyces yeasts are metabolically active during grape must fermentations and can contribute with enzymes and metabolites to enhance the complexity and to define the final wine aroma. Nowadays, the use of non-Saccharomyces yeasts in combination with Saccharomyces cerevisiae is a state-of-the art strategy to improve wine composition and/or wine sensory properties. The present paper deals with the new yeast strains of Metschnikowia fructicola and S. cerevisiae, that were selected as representatives of the yeast microbiota isolated from grapes and grape juice of Aglianico cultivar. S. cerevisiae was utilized both as single strain starter and in combination with M. fructicola in experimental fermentations of Aglianico must. The dynamic of yeast populations was evaluated during the fermentation process analyzing the wine volatile compounds profile. The volatile compounds were identified by SPME-GC/MS. The results, showed that the multiple indigenous yeast starter was able to modulate the volatile compounds profiles and improve the aromatic complexity of wine, with a higher content of esters and terpenes.

Volatile composition plays a fundamental role in wine aroma and quality. However, the concentrations of volatiles depend on climate conditions and agricultural practices, such as irrigation. The aim of the current study was to assess the effects of irrigation on the volatile composition and sensory characteristics of wines from Vitis vinifera (L.) cultivar ‘Albarino’ in two zones of NW Spain (Rias Baixas and Ribeiro) during three consecutive years (2012, 2013, and 2014). Irrigation was scheduled by the vine grower in Rias Baixas, whereas it was fixed at 50% of the estimated crop evapotranspiration in Ribeiro. Water was applied in August, mainly, in Rias Baixas and from mid-July to mid-August in Ribeiro. Irrigation significantly altered the concentrations of several volatiles, which differed between zones and years. For instance, wines from the irrigated treatment had lower concentrations of isoamyl acetate, 2-phenylethyl acetate, and ethyl hexanoate than those from the rain-fed treatment in Rias Baixas. In contrast, irrigation increased the concentrations of ethyl hexanoate and ethyl octanoate, while reduced those of free terpenes in wines from Ribeiro. Mainly, these differences between zones were caused by the climate conditions of each region.

An in-mouth headspace sorptive extraction (HSSE) procedure for the in-mouth volatile sampling of wine aroma compounds during wine tasting has been developed. The procedure is based on the application of a PDMS (polydimethylsiloxane) twister contained inside a tailored made glass tube placed into the headspace of the mouth after rinsing and spitting-off the wine, which is then followed by gas chromatography mass spectrometry analysis (GCMS). Various parameters that might affect the performance of the method (extraction time, aroma concentration) were firstly investigated. Despite the short selected in-mouth extraction time (30 s); the application of the in-mouth HSSE procedure using real wines allowed the detection of >30 volatile compounds from different chemical families in the oral cavity in a single run, and which are also present in the wine at very low concentrations. Additionally, the in-mouth HSSE profile allowed us to distinguish between wines types (with different non-volatile and volatile composition) in a similar way to that when using data from the headspace of the wine (wine-HSSE-GCMS). The simplicity, sensitivity, good repeatability and the easy automatization of this procedure, makes this technique a reliable and feasible tool to determine the chemical and biochemical changes of these compounds in the mouth in real physiological conditions providing useful –in vivo analytical data to better correlate with sensory studies., This work was financially supported by the Spanish Ministry of Economy and Competitiveness (MINECO) (project AGL 2016 78936-R).

Interaction studies are used in sensory evaluation to elucidate the complex influences (additive, masking, synergistic) that various compounds have on the perception of wine aroma. To these, the interactions between the matrix and the compounds of interest add another layer of complexity. Unlike previous interaction studies, the current work used a rapid method, Projective Mapping (PM) coupled with intensity of attributes, to evaluate the interaction effects two thiols (3-mercaptohexan-1-ol, 3MH, and 3-mercaptohexyl acetate, 3MHA) have in various matrices. The matrices used were increasingly complex, from model wine to partially dearomatized neutral Chenin Blanc to commercial wines. The results reflected the effect of the thiols interaction with the matrix more than that between compounds. The methodology proposed for the data handling highlighted possible advantages and shortcomings of the Projective Mapping with intensity approach. The choice of base matrix as well as the sensory method are relevant when studying interaction effects, and are dependent on the desired outcome of the experiment.

Styrene analogs are known to be naturally synthesized in the leaves of pears and in other plant species, including several trees in the Styracaceae family. Styrene analogs are potential contributors to the aroma of wine, perfumes, pharmaceuticals, and other fermented foods and beverages. In addition, styrene analogs perform important ecological functions such as insecticidal and antifeedant activities against insects. We showed here that exogenous applications of styrene and p-hydroxystyrene caused a dramatic reduction the number of eggs laid by psylla and of subsequent nymph survival. Despite their importance specific reactions that lead to the biosynthesis of the styrene analogs in pear are unknown. To identify genes involved in the synthesis of these metabolites, existing genome databases of the Rosaceae were screened for pear genes with significant sequence similarity to bacterial phenolic acid decarboxylase. Herein described are the isolation and characterization of a pear phenolic acid decarboxylase, designated PyPAD1, which catalyzed the decarboxylation of p-coumaric acid and ferulic acid to p-hydroxystyrene and 3-methoxy-4-hydroxystyrene respectively. Its apparent Km values for p-coumaric acid and ferulic acid were 34.42 and 84.64 μM, respectively. The PyPAD1 preferred p-coumaric acid to ferulic acid as a substrate by a factor of 2.4 when comparing catalytic efficiencies in vitro. Expression analysis of PyPAD1 showed that the gene was transcribed in all five pear genotypes examined. However, transcript abundance was increased in correlation with the presence of p-hydroxystyrene in resistant cultivars Py-701 and Py-760 and in the sensitive cultivar Spadona when grafted on these resistant cultivars. Thus, PyPAD1 appears to be responsible for the decarboxylation of the p-coumaric acid, and for the production of metabolites that are active against pear psylla.

The dynamic pattern of volatiles during Pinot Noir winemaking in monsoon climate with yeast extracellular extract (EE) treatment was analyzed. EE from selected Pichia fermentans and Rhodotorula mucilaginosa strains, and almond β-glucosidase were added after 12-h alcohol fermentation, and the volatiles were determined every 24 h by GC–MS. After 6-month storage, wine aroma was evaluated instrumentally as well as by well-trained panelists. Results showed that enzyme treatments improved the contents of both varietal and fermentative volatiles. The levels of C6 compounds, terpenes, and higher alcohols increased constantly during alcohol fermentation, whereas acetates, short and medium chain fatty acid ethyl esters, phenylethyls, and fatty acids increased first, followed by gradual decrease. EE treatment retarded the decrease of fruity ester content in wine. Mathematical regression between wine aroma and volatiles showed that the relatively higher contents of acetates, ethyl esters, and C13-norisoprenoids in 6-month EE-treated wine were responsible for the improvement in floral aroma intensity.

Background and Aims The climate‐change driven uncoupling of grape (Vitis vinifera L.) berry ‘sugar‐ripeness’ and ‘flavour‐ripeness’ necessitates an improved understanding of the sugar/flavour nexus. Methods and Results Analysis of grape metabolites and wine volatiles derived from Riesling berries of peduncle‐girdled and Control bunches over the course of 30 days provided time‐dependent insights into changes to grape and wine composition associated with phloem import. Girdling resulted in stable berry mass and concentration of sugar and cytokinin and in reduced concentration of amino acids. Such changes to grape composition correlated with a lasting increase in wine monoterpenoids and a transient reduction in fermentation‐derived wine volatiles. Conclusions Oxidative stress and restricted amino acid import, not sugar accumulation, were identified as possible elicitors for the increased accumulation of varietal wine aroma compounds in Riesling. Significance of the Study The concentration and composition of berry amino acids and cytokinin concentration in grapes during the later stages of rapid sugar accumulation may represent potential targets for vineyard management strategies and grapevine breeding to counter climate‐change driven modifications to the wine volatile profile of aromatic cultivars.

The aim of this study was to evaluate the potential application of cell-surface-displayed β-glucosidase (BGL) in wine aroma enhancement. Gene cassettes for the surface display of Aspergillus niger BGL were constructed using different promoters ( GPD and SED1) and glycosylphosphatidylinositol (GPI) anchoring regions (Sag1, Sed1, and Cwp2). The differences in surface-display cassettes, the tolerance of the displayed BGL to typical winemaking conditions, and the hydrolysis capacity for the liberation of grape aroma glycosides were analyzed. Results revealed that simultaneous utilization of GPD promoter and Sed1 anchoring domain achieved the highest BGL activity. The displayed BGL exhibited relatively high activity at pH 3.0 and at glucose concentration below 2.5% (w/v), compared to commercial enzyme (AR 2000), but exhibited no significant difference under varying ethanol concentrations. Furthermore, the surface-displayed BGL presented better ability to release free terpenols compared to AR 2000. Therefore, a surface-display system could provide a new viable solution for enhancing wine aroma.

Malolactic fermentation (MLF) is a process in winemaking responsible for the conversion of L-malic acid to L-lactic acid and CO 2 , which reduces the total acidity, improves the biological stability, and modifies the aroma profile of wine. MLF takes place during or after alcoholic fermentation and is carried out by one or more species of lactic acid bacteria (LAB), which are either present in grapes and cellars or inoculated with malolactic starters during the winemaking process. Although the main bacterium among LAB used in commercial starter cultures for MLF has traditionally been Oenococcus oeni, in the last decade, Lactobacillus plantarum has also been reported as a malolactic starter, and many works have shown that this species can survive and even grow under harsh conditions of wine (i.e., high ethanol content and low pH values). Furthermore, it has been proved that some strains of L. plantarum are able to conduct MLF just as efficiently as O. oeni. In addition, L. plantarum exhibits a more diverse enzymatic profile than O. oeni, which could play an important role in the modification of the wine aroma profile. This enzymatic diversity allows obtaining several starter cultures composed of different L. plantarum biotypes, which could result in distinctive wines. In this context, this review focuses on showing the relevance of L. plantarum as a MLF starter culture in winemaking. Fil: Brizuela, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina Fil: Tymczyszyn, Emma Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina Fil: Semorile, Liliana Carmen. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina Fil: Valdes la Hens, Danay. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina Fil: Delfederico, Lucrecia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina Fil: Hollmann, Axel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Centro de Investigación en Biofísica Aplicada y Alimentos. - Universidad Nacional de Santiago del Estero. Centro de Investigación en Biofísica Aplicada y Alimentos; Argentina Fil: Bravo Ferrada, Barbara Mercedes. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Microbiología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina