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The volatile composition of grapes has a direct impact on the final aromatic composition of wine and plays a crucial role in determining its quality. Various factors, such as agronomic practices, climatic conditions or grape variety, can influence the volatile composition of grape juices. This study aimed to determine the influence of three doses of urea, applied at two different phenological stages (pre-veraison and veraison), on the volatile composition of Tempranillo musts, during two consecutive seasons. The urea application did not have an impact on the yield of the vineyard or the general parameters of the Tempranillo must. However, the three different concentrations of urea modified the volatile composition. Specifically, the higher concentration of urea improved the terpenoids, C13 norisoprenoids, and benzenoid compounds in grape juice. Additionally, when urea treatments were applied at pre-veraison, terpenoids, C13 norisoprenoids, esters, and benzenoid compounds were improved in Tempranillo must. However, the weather was an important factor influencing the volatile compounds in Tempranillo musts. Consequently, foliar applications of urea could be an interesting viticulture practice in order to enhance the volatile compounds in Tempranillo musts.

Selective enhancement of wine aroma was achieved using a broad spectrum of exogenous glycosidases. Eight different enzyme preparations were added to Verdejo wine, resulting in an increase in the levels of varietal volatile compounds compared to the control wine after 15 days of treatment. The enzyme preparations studied were robust under winemaking conditions (sulfur dioxide, reducing sugars, and alcohol content), and no inhibition of β-glucosidase activity was observed. Significant differences were detected in four individual terpenes (α-terpineol, terpinen-4-ol, α-pinene, and citronellal) and benzyl alcohol in all the treated wines compared to the control wine, contributing to the final wine to varying degrees. In addition, a significant increase in the other aromatic compounds was observed, which showed different patterns depending on the enzyme preparation that was tested. The principal component analysis of the data revealed the possibility of modulating the different aromatic profiles of the final wines depending on the enzyme preparation used. Taking these results into account, enhancement of the floral, balsamic, and/or fruity notes of wines is possible by using a suitable commercial enzyme preparation. [ABSTRACT FROM AUTHOR]

Varietal thiol concentration in wine is influenced by numerous factors, of which grape variety and winemaking practices are often highlighted as the most important. Therefore, the aim of this work was to study the effects of grape clone and yeast strain (Saccharomyces and non-Saccharomyces) on the varietal thiols concentrations and sensory characteristics of Graševina (Vitis vinifera L.) white wines. Two grape clones were evaluated (OB-412 and OB-445) along with three different commercial yeast strains (Saccharomyces cerevisiae Lalvin Sensy and Sauvy, and Metschnikowia pulcherrima Flavia). The results showed that the concentration of varietal thiols in Graševina wines amounted up to a total of 226 ng/L. The clone OB-412 was characterized by its significantly higher concentrations, especially of 3-sulfanylhexanol (3SH) and 3-sulfanylhexyl acetate (3SHA). Moreover, alcoholic fermentation with pure S. cerevisiae Sauvy yeasts generally resulted in higher thiol concentrations, while sequential fermentation involving M. pulcherrima positively affected only the 4-methyl-4-sulfanyl-pentan-2-one (4MSP) concentration. Finally, sensory analysis showed that fermentation with pure S. cerevisiae Sauvy yeast also produced more desirable wines. The results suggest that clonal, and especially yeast strain, selections are important modulators of the aroma and sensory properties of wine. [ABSTRACT FROM AUTHOR]

Selective enhancement of wine aroma was achieved using a broad spectrum of exogenous glycosidases. Eight different enzyme preparations were added to Verdejo wine, resulting in an increase in the levels of varietal volatile compounds compared to the control wine after 15 days of treatment. The enzyme preparations studied were robust under winemaking conditions (sulfur dioxide, reducing sugars, and alcohol content), and no inhibition of β-glucosidase activity was observed. Significant differences were detected in four individual terpenes (α-terpineol, terpinen-4-ol, α-pinene, and citronellal) and benzyl alcohol in all the treated wines compared to the control wine, contributing to the final wine to varying degrees. In addition, a significant increase in the other aromatic compounds was observed, which showed different patterns depending on the enzyme preparation that was tested. The principal component analysis of the data revealed the possibility of modulating the different aromatic profiles of the final wines depending on the enzyme preparation used. Taking these results into account, enhancement of the floral, balsamic, and/or fruity notes of wines is possible by using a suitable commercial enzyme preparation.

Cold maceration (CM) is widely applied in winemaking to improve wine aroma and overall quality. However, more efficient CM techniques for industrial-scale winemaking are still needed. This study examined the impact of CM with indigenous cryotolerant Metschnikowia pulcherrima Mp0520 (Mp-CM) on the Muscat wine aromatic characteristics. The results demonstrated a significant divergence in the types and concentrations of aroma compounds between Mp-CM wine and the control. The Mp-CM wine exhibited a significantly higher terpenes content, resulting in a Muscat wine characterized by terpenes, compared to the control predominated by esters. Additionally, the Mp-CM wine demonstrated elevated levels of α-terpineol and terpinolene, potentially enhancing the varietal aroma stability of Muscat wine. Furthermore, Mp-CM gave Muscat wine a heightened fruity aroma and a more complex aroma. These findings suggested that the Mp-CM utilized in this study offered promising avenues for enhancing the variety aroma characteristics of Muscat wine on large scale winemaking. • Mp0520 effects the fungal microbial community in cold maceration broth. • Mp0520 shows great increase in cell wall hydrolase activities in the maceration broth. • Mp0520 increases the content of terpenes in wine. • Mp0520 highlights wine varietal characteristics and improves wine aroma quality. • Mp0520 shows wide application potential in winemaking. [ABSTRACT FROM AUTHOR]

β‐Glucosidase is a key enzyme that hydrolyzes nonvolatile glycosylated precursors of aroma compounds and enhances the organoleptic quality of wines. In this study, a novel β‐glucosidase from Hanseniaspora uvarum Yun268 was localized, purified, and characterized. Results indicated that β‐glucosidase activity was mainly distributed within the cells. After purification via ammonium sulfate precipitation combined with chromatography, β‐glucosidase specific activity increased 8.36 times, and the activity recovery was 56.90%. The enzyme had a molecular mass of 74.22 kDa. It has a Michaelis constant (Km) of 0.65 mmol/L, and a maximum velocity (Vmax) of 5.1 nmol/min under optimum conditions; and Km of 0.94 mmol/L, and Vmax of 2.8 nmol/min under typical winemaking conditions. It exhibited the highest activity at 50°C and pH 5.0 and was stable at a temperature range of 20–80°C and pH range of 3.0–8.0. The enzyme has good tolerance to Fe3+, especially maintaining 93.68% of its activity with 10 mmol/L of Fe3+. Ethanol (<20%) and glucose (<150 g/L) inhibited its activity only slightly. Therefore, β‐glucosidase from H. uvarum Yun268 has excellent biochemical properties and a good application potential in winemaking. Practical Application: Winemaking is a biotechnological process in which exogenous β‐glucosidase is used to overcome the deficiency of endogenous β‐glucosidase activity in grapes. By localizing, purifying, and characterizing of β‐glucosidase from Hanseniaspora uvarum Yun268, it is expected to reveal its physical and chemical characteristics to evaluate its oenological properties in winemaking. The results may provide the basis for promoting the release of varietal aroma and improving wine sensory quality in the wine industry. [ABSTRACT FROM AUTHOR]

Varietal thiol concentration in wine is influenced by numerous factors, of which grape variety and winemaking practices are often highlighted as the most important. Therefore, the aim of this work was to study the effects of grape clone and yeast strain (Saccharomyces and non-Saccharomyces) on the varietal thiols concentrations and sensory characteristics of Graševina (Vitis vinifera L.) white wines. Two grape clones were evaluated (OB-412 and OB-445) along with three different commercial yeast strains (Saccharomyces cerevisiae Lalvin Sensy and Sauvy, and Metschnikowia pulcherrima Flavia). The results showed that the concentration of varietal thiols in Graševina wines amounted up to a total of 226 ng/L. The clone OB-412 was characterized by its significantly higher concentrations, especially of 3-sulfanylhexanol (3SH) and 3-sulfanylhexyl acetate (3SHA). Moreover, alcoholic fermentation with pure S. cerevisiae Sauvy yeasts generally resulted in higher thiol concentrations, while sequential fermentation involving M. pulcherrima positively affected only the 4-methyl-4-sulfanyl-pentan-2-one (4MSP) concentration. Finally, sensory analysis showed that fermentation with pure S. cerevisiae Sauvy yeast also produced more desirable wines. The results suggest that clonal, and especially yeast strain, selections are important modulators of the aroma and sensory properties of wine.

This study aimed at determining the changes induced by two S. cerevisiae strains, (IONYS wf™ and Lalvin ICV D254™) on the sensory and chemical aroma profiles of Tempranillo wine, after fermentation and after ageing. The 64 aroma molecules determined were grouped attending to sensory and chemical similarity into 17 aroma vectors. Sensory studies included a sorting task and a descriptive analysis by flash profile with a trained panel. Results revealed that, even if ageing is the dominant factor, the strain of yeast introduces significant and consistent differences, both in sensory and aroma vector profiles (11 out of 17 affected). Wines made with D254 contained higher levels of ethyl esters, acetic acid, cinnamates and ethyl acetate and lower levels of linear fatty acids, β-damascenone, acetaldehyde, higher alcohols and lactones than those made with IONYS. The first profile was related to black and fresh fruit notes, while the second to white and compote fruits.

Dehydration or drying of grapes is one of the most important steps in the production of Croatian traditional dessert wine Prošek. The natural sun drying of grapes is the traditionally used method in Prošek production. Alternative methods, such as dehydration under controlled conditions, have been studied as safer and faster methods than the traditional sun drying but without precise knowledge of the effect on volatile compounds. The objective of this work was to study how dehydration of grapes carried out in a greenhouse and an environmentally controlled chamber impacts on the free and glycosidically bound volatile compounds of native grape cv. 'Maraština'. The 36 volatile compounds were identified and quantified using headspace solid-phase micro extraction coupled with gas chromatography-mass spectrophotometry (HS-SPME-GC/MS). The results showed that the aroma profile of dehydrated grapes was significantly different from that of fresh grapes. Regarding free forms, significant increases in the concentration of 2-methyl-1-propanol, 1-butanol, 2-hexen-1-ol, 1-hexanol, ethyl hexanoate, hexyl acetate, o-cymene, linalool oxide, and terpinen-4-ol and geraniol were found in greenhouse-dried grapes, whereas increases in cis-limonene-epoxide, trans-limonene epoxide, and γ-hexalactone were higher in chamber-dried grapes compared to greenhouse-dried grapes. Glycosidically bound forms of o-cymene, linalool oxide, linalool, and terpinen-4-ol were increased in both types of drying, whereas β-damascenone was increased only in greenhouse-dried grapes. [ABSTRACT FROM AUTHOR]

The potential of pulsed electric fields (PEF) for improving polyphenol extraction, decreasing maceration and increasing aroma compounds in the course of the winemaking process were investigated. Twelve tons of Garnacha grapes were processed at a flow rate of 2500 kgh-1, and wines obtained from untreated and PEF-treated (4.0kV cm-1) grapes after 3 and 6 days of maceration were compared. The highest values of total anthocyanin, total polyphenolic, tannin content, and color intensity were obtained with PEF-treated grapes as well as when the maceration period was extended. The higher tannin concentration observed in PEF- treated wines was a consequence of a higher degree of extraction of tannins located in the grape skins rather than in the seeds. Finally, PEF contributed to the extraction of some individual precursors positive for aroma. These results, obtained at conditions very close to requirements at industrial scale, may encourage the adoption of PEF technology by wineries. [ABSTRACT FROM AUTHOR]

Nitrogen is an important component that affects grapevine growth and the formation of flavor-associated volatile chemicals in grape berries. Dynamic changes in amino acids and aroma compounds in Chardonnay grape berry preharvest treated with different doses of salicylic acid (SA) at onset and one week later of veraison stage were evaluated. Exogenous 1- or 3-mM SA application significantly increased the content of total soluble solid and titratable acid in grapes, while 5 mM SA tended to decrease their levels. Compared with the control, the concentration of yeast assimilable nitrogen were 9.3% and 14.6% higher in 3 mM SA-treated grapes in 2021 and 2022, respectively. Preharvest 3 mM SA treatment efficiently enhanced the accumulation of nine amino acids, including tryptophan, phenylalanine, tyrosine, aspartic acid, lysine, asparagine, valine, isoleucine and histidine, as well as the concentration of total amino acid with and without proline in the two grape vintages. Higher concentrations of primary phenylalanine-derivatives and terpenoids and lower levels of C 6 compounds in grapes treated with 3 mM SA were observed during the 2021–2022 season. Overall, SA improved the quality of wine grape in a dose dependent manner, while the response of berries to SA treatment also showed effects of the vintage. [Display omitted] • Preharvest SA treatment improved the YAN content in Chardonnay grape during development. • More aromatic amino acids accumulated in grapes treated with 3 mM SA. • Phenylalanine-derived volatiles and terpenoids were upregulated by exogenous SA. • 3 mM SA treatment improves the quality traits of grape fruits. [ABSTRACT FROM AUTHOR]

Dehydration or drying of grapes is one of the most important steps in the production of Croatian traditional dessert wine Prošek. The natural sun drying of grapes is the traditionally used method in Prošek production. Alternative methods, such as dehydration under controlled conditions, have been studied as safer and faster methods than the traditional sun drying but without precise knowledge of the effect on volatile compounds. The objective of this work was to study how dehydration of grapes carried out in a greenhouse and an environmentally controlled chamber impacts on the free and glycosidically bound volatile compounds of native grape cv. ‘Maraština’. The 36 volatile compounds were identified and quantified using headspace solid-phase micro extraction coupled with gas chromatography-mass spectrophotometry (HS-SPME-GC/MS). The results showed that the aroma profile of dehydrated grapes was significantly different from that of fresh grapes. Regarding free forms, significant increases in the concentration of 2-methyl-1-propanol, 1-butanol, 2-hexen-1-ol, 1-hexanol, ethyl hexanoate, hexyl acetate, o-cymene, linalool oxide, and terpinen-4-ol and geraniol were found in greenhouse-dried grapes, whereas increases in cis-limonene-epoxide, trans-limonene epoxide, and γ-hexalactone were higher in chamber-dried grapes compared to greenhouse-dried grapes. Glycosidically bound forms of o-cymene, linalool oxide, linalool, and terpinen-4-ol were increased in both types of drying, whereas β-damascenone was increased only in greenhouse-dried grapes.

Selective enhancement of wine aroma was achieved using a broad spectrum of exogenous glycosidases. Eight different enzyme preparations were added to Verdejo wine, resulting in an increase in the levels of varietal volatile compounds compared to the control wine after 15 days of treatment. The enzyme preparations studied were robust under winemaking conditions (sulfur dioxide, reducing sugars, and alcohol content), and no inhibition of β-glucosidase activity was observed. Significant differences were detected in four individual terpenes (α-terpineol, terpinen-4-ol, α-pinene, and citronellal) and benzyl alcohol in all the treated wines compared to the control wine, contributing to the final wine to varying degrees. In addition, a significant increase in the other aromatic compounds was observed, which showed different patterns depending on the enzyme preparation that was tested. The principal component analysis of the data revealed the possibility of modulating the different aromatic profiles of the final wines depending on the enzyme preparation used. Taking these results into account, enhancement of the floral, balsamic, and/or fruity notes of wines is possible by using a suitable commercial enzyme preparation.

Hops are among the most important ingredients in beer that contribute to beer flavor. Consequently, novel types of hops have been bred and widely used worldwide. For example, the Sorachi Ace hop imparts characteristic varietal aromas, including woody, pine-like, citrus, dill-like, and lemongrass-like aromas, to the finished beer. In our previous study, the unique volatile compound geranic acid was significantly detected only in the test beer brewed with the Sorachi Ace hop; moreover, the coexistence of geranic acid and other hop-derived flavor compounds could result in the characteristic aroma of the Sorachi Ace beers. In this study, selected hop-derived flavor compounds, including geranic acid, were compared among 17 hop varieties. The geranic acid content in the Sorachi Ace hop was the highest among the studied hops. We also investigated the behavior of geranic acid and related flavor compounds throughout the fermentation process. The content of geranic acid was higher than those of the other compounds during fermentation. Next, we compared the concentrations of these compounds in kettle-, late-, and dry-hopped beers using Sorachi Ace hop. The results revealed that geranic acid remained at higher concentrations from the worts to finished beers despite the decrease in the content of other hop-derived flavor compounds as a result of evaporation and/or other factors during brewing. Further, geranic acid could remain at high levels in the test-brewed beers with Sorachi Ace hops because of its behavior as an acid throughout the brewing process, including during wort boiling and fermentation.

Pulsed electric field (PEF) processing of white grapes (cv. Garganega) after crushing was studied on pilot-plant scale, to investigate the effects of the treatment on must and wine composition, wine color and predisposition to browning, wine aroma compounds and extraction of aroma precursors from grapes. PEF pre-treatment of grapes did not change the must or wine basic composition, nor was it able to modify the evolution of alcoholic fermentation. By contrast, PEF produced an increase in total dry extract, wine color and total phenolics. Treatment corresponding to a total specific energy of 22 kJ kg −1 allowed more intense extraction of varietal aroma precursors without provoking excessive color evolution and extraction of phenolic compounds, apparently increasing the stability of wine towards oxidation. Due to the few papers available on this subject, PEF applications on white grapes should be optimized in further experiments. [ABSTRACT FROM AUTHOR]

An alternative to improve grape quality is the elicitor application to the vineyard due its implication to induce defense mechanisms involved in the synthesis of secondary metabolites. There are few studies about the influence of elicitors on grape volatile composition. The aim of this work was to investigate the influence of methyl jasmonate (MeJ) foliar application to Tempranillo grapevines on grape aroma composition over three consecutive vintages. In the first vintage, MeJ treatment improved p-cymene, methyl jasmonate, and hexanal synthesis, and degraded 2-hexen-1-ol acetate, (Z)-3-hexen-1-ol, and n -hexanol. In the second season, the content of several terpenes, β -damascenone, methyl jasmonate, esters, benzenoids and (Z)-3-hexen-1-ol was diminished after MeJ application. In the third vintage, the synthesis of several volatile compounds considered positive contributors for grape aroma was improved by MeJ application. In conclusion, the effect of MeJ foliar application on grape volatile content was mainly dependent on the vintage. [ABSTRACT FROM AUTHOR]

Recently, various technologies which utilise fermentation with skins have been developed for obtaining distinct white wines. This study first reports the dynamic changes of volatiles and phenols that occur during skin fermentation in white winemaking. Volatiles were analysed by solid-phase extraction (SPE), solid-phase microextraction (SPME) and gas chromatography (GC), and phenols by ultra-performance liquid chromatography (UPLC), both with mass spectrometric detection. Monoterpenols increased during the first 3 days of skin fermentation, after which certain glycosides decreased, but were higher than in control. The presence of skins reduced ho-trienol, β-damascenone, acids and esters. After a 1–3 days lag phase, skin fermentation caused a constant increase of most phenols. It was estimated that skin fermentation up to 1–3 days might be beneficial for monoterpenol varietal aroma, which should be re-evaluated through further studies. Longer durations promoted phenol extraction more strongly, which is possibly suitable for obtaining more distinct wines or blending components. [ABSTRACT FROM AUTHOR]

During a two-year study, the effect of different grape mash maceration treatments (skin contact at 20 °C for 10, 20 and 30 h) and cryomaceration (skin contact at 7 °C for 10, 20 and 30 h) on the concentration of free and bound monoterpenes and total phenols in Malvazija istarska wine (the most spread white wine variety in Istria) was monitored. Monoterpenic alcohols linalool, a-terpineol, citronellol, nerol and geraniol were determined by gas chromatography after isolation on octadecylsilica (C18) sorbent and elution with pentane/dichlorometane ratio of 2:1, while total phenols were determined spectrophotometrically with Folin-Ciocalteau reagent. Sensory evaluation of wines was performed using the Buxbaum method. The obtained results show that linalool and geraniol are the most abundant monoterpenes in Malvazija istarska, and that grape mash maceration treatments cause significant increase of free and bound monoterpene concentrations compared to those in control treatment wine obtained without maceration. The content of phenols, which are subject to oxidation, was found to be significantly lower in wines produced by cryomaceration treatments, while in those produced by maceration at 20 °C the concentration of total phenols increased proportionally with the duration of maceration, negatively influencing wine quality by causing higher colour intensity and bitter taste.

Dimethyl sulfide (DMS) is a sulfur containing volatile that enhances general fruity aroma and imparts aromatic notes in wine. The most important precursor of DMS is S- methylmethionine (SMM), which is synthesized by grapes and can be metabolized by the yeast S. cerevisiae during wine fermentation. Precursor molecules left after fermentation are chemically converted to DMS during wine maturation, meaning that wine DMS levels are determined by the amount of remaining precursors at bottling. To elucidate SMM metabolism in yeast we performed quantitative trait locus (QTL) mapping using a population of 130 F2-segregants obtained from a cross between two wine yeast strains, and we detected one major QTL explaining almost 30% of trait variation. Within the QTL, gene YLL058W and SMM transporter gene MMP1 were found to influence SMM metabolism, from which MMP1 has the bigger impact. We identified and characterized a variant coding for a truncated transporter with superior SMM preserving attributes. A population analysis with 85 yeast strains from different origins revealed a significant association of the variant to flor strains and minor occurrence in cheese and wine strains. These results will help selecting and improving S. cerevisiae strains for the production of wine and other fermented foods containing DMS such as cheese or beer. • Detection of a new allele with superior preservation of S-methylmethionine (SMM). • High affinity SMM transporter gene MMP1 is the strongest phenotypic contributor. • Single nucleotide polymorphism causing an early STOP codon in MMP1 is decisive. • Variant mostly found in flor yeasts used for the production of characterful wines. • CRISPR/Cas9 mediated base pair exchange in MMP1 resulted in better SMM. [ABSTRACT FROM AUTHOR]

[Display omitted] • Varietal aroma of Vidal blanc in late harvest was different from that in maturation. • Characteristic VOCs and the diversity of microeukaryotes were correlated. • Quantification of stochastic process on shaping microeukaryotic communities. • Important CAZy pathways of epiphytic microbes were identified. • Correlation matrix for high expressed GTs/GHs and active yeasts was established. To study the effects of microeukaryotic communities on development of varietal aroma of Vidal blanc grape during late harvest, metagenomics, gas chromatography–mass spectrometry, climate factors and scanning electron microscopy were jointly used to discover how freeze–thaw stress influences grape skin and shapes the microeukaryotic consortia. Most free terpenes, monoterpenes and C13-norisoprenoids developed during late harvest. Freeze-thaw cycles caused damage of the wax layer and microfissures on the cuticle of grape berries. This increased nutrients availability and supported the dominance of oxidative and fermentative ascomycetous populations. Microbial assemblages possessed certain ecosystem functions, which correlated to the development of characteristic volatile organic compounds, such as free terpenes and phenylalanine derivatives. Significantly upregulated genes of CAZy were identified as FENNEDOB12352, OJNJMGIN252777, EGHMEMAM161340, EGHMEMAM158447, KKFIDJDF144524, BEDCFLNK31943, LHALBBHN88115, BEDCFLNK41042. Zymoseptoria tritici , Kluyveromyces lactis , Yarrowia lipolytica , and Pichia kudriavzevii were selected as key factors in yeast assemblage. [ABSTRACT FROM AUTHOR]

The incidence of cupric sprayings using a commercial formula of Bordeaux mixture (containing 20% of copper sulphate or an organic fungicide), on Sauvignon grapes composition and wines varietal aroma, has been studied in three areas of the Bordeaux region (Entre-deux-Mers, Graves, Médoc). Copper content has been noticed to increase in the clarified juices in all cases after these treatments, values ranging from 0,3 mg/l to 14,5 mg/l, whereas natural copper content did not exceed 0,4 mg/l. The value of residual copper by treatment was found to be significantly different from one year to the other (2 to 3,5 mg/l in 1993, 0,3 to 0,9 mg/l in 1994 and 0,7 to 0,9 mg/l in 1995) mainly due to the grapes composition and the different climatic conditions, whereas for the same year in the three different areas, this value was almost the same. The operation known as «skin contact» during which juices were left with their skins under CO2 at 10°C, during 18 hours before pressing, was found to decrease copper content in the clarified juices from 60 p. cent to 80 p. cent, whereas immediate pressing of grapes led to a decrease of only 20 p. cent ; the combination of copper during skin contact with glutathione, which is present in Sauvignon grapes, is a possible explanation. Under the ripening conditions of Bordeaux's oceanic temperate climate, we have noticed that even one single spray with a commercial formula of Bordeaux mixture at 3 000 g/ha, between the stage of closing of the cluster and the post-veraison, is sufficient to significantly reduce the content in 4-mercapto-4-methylpentan-2-one (4-MMP), a main component of the characteristic Sauvignon wines aroma. Increase of the introduced copper quantities in the must as well as of the number of applications, results in a greater reduction of the content in this thiol, as 4-MMP reacts with copper residues during alcoholic fermentation while its precursor is revealed into an aroma. Nevertheless, the experiments with a polymer that eliminates copper from the juice prior to alcoholic fermentation, showing in some cases no recovery in the wines 4-MMP content, lead us to the hypothesis that copper might as well intervene during ripening of the grapes, causing thus a limitation of the aroma's precursor synthesis. By the sensory analysis, Sauvignon wines produced from copper treated vines showed much less characteristic aroma than those produced from not treated vines (having nevertheless been protected by an organic fungicide) and were lower graded. While the average grade for the last ones was 7,9/10, this grade was lowered to 2,9/10 and to 2,8/10 for the samples produced after one and two or three vine's copper treatments respectively. Grapes sugar concentration can also be affected by the vine's cupric treatments. Throughout the 3-year study, differences in sugar concentration up to 40 g/l have been observed, especially concerning the treatments made between stages of closing of the cluster and veraison. Nevertheless, sugar content seems highly dependent on the number of cupric applications, the period of their application as well as climatic conditions during vine sprayings.

4-mercapto-4-methylpentan-2-one (4MMP), a powerful aromatic component from Sauvignon variety, is present at trace levels in the wines from this cultivar. A method is proposed ta measure the amount of 4MMP in Sauvignon wines. It combines the extraction of wines volatile constituents using a dynarnic headspace technique and the selective reaction between thiols and p-hydroxymercuribenzoatc (pHMB). This combination is reversible in presence of an excess of cystein or glutathione. Finally, the organic extract is injected on agas chromatograph coupled with a flame photometric detector. Using this method, 4MMP content in Sauvignon wines can be determined with good repetability and sensitivity. These results enable us to evalue the incidence of viticultural and oenological aspects on the level of this aromatic component in Sauvignon wines.

THE CURRENT STUDY AIMS TO EXPLORE THE AROMATIC COMPOSITION OF THREE GRAPE VARIETIES OF LOCAL SELECTION FROM REPUBLIC OF MOLDOVA. THE GRAPES WERE ANALYZED USING A HEADSPACE (HS) TECHNIQUE COUPLED TO A GAS CHROMATOGRAPHY (GC) SYSTEM COMPOSED FROM A SINGLE QUADRUPOLE MASS-SPECTROMETER (MS) AND A THREE-DIMENSIONAL AUTOMATED SYSTEM FOR THE INJECTION OF SAMPLES. HS COUPLED WITH GC/MS IS FOUND TO BE A SIMPLE, QUICK, AND SENSITIVE APPROACH AND IS SUITABLE FOR CHARACTERIZATION OF GRAPE AROMA COMPOUNDS WITHOUT COMPLICATED SAMPLE PREPARATION PROCEDURES. GRAPE JUICE WAS CHARACTERIZED BY "AROMAGRAMS", A SET OF IDENTIFIED COMPONENTS WITH CORRESPONDING RELATIVE ABUNDANCES. ACCORDING TO COINCIDENCE OF GC RETENTION DATA AND ON THE SIMILARITY OF ODOR WITH STANDARDS WERE IDENTIFIED THE CHEMICAL COMPOUNDS RESPONSIBLE FOR PEAK AREAS. [ABSTRACT FROM AUTHOR]

Nous nous sommes intéressés à certaines nuances aromatiques caractéristiques des vins de Sauvignon. En utilisant le couplage de la chromatographie en phase gazeuse à la détection odométrique en sortie de colonne, nous avons mis en évidence dans des extraits de vins de Sauvignon une zone odorante rappellant le buis et le bourgeon de cassis. Une méthode, basée sur la mesure de la durée de perception de cette odeur caractéristique au cours de l'analyse odométrique, permet d'apprécier son intensité dans les vins. Nous démontrons ainsi le rôle de la souche de levure qui réalise la fermentation alcoolique sur l'intensité de l'arôme variétal des vins de Sauvignon.

The influence of different grape mash maceration treatments on the varietal and secondary aroma profiles of wines produced from an aromatic red grape variety, Mugkat ruža porečki, have been investigated. Two essentially different tectmiques were applied, fermentative maceration at room temperature and prefermentative cryomaceration, both in durations of one, three and five days. Generally, higher concentrations of free and bound varietal aroma compounds were found in wines obtained by maceration at room temperature in relation to cryomaceration. Regarding the effect of the duration of maceration, the highest concentrations were determined in wines obtained by three-day maceration treatments, in both fermentative and cryomaceration treatments. Secondary aroma compounds followed a less uniform pattern. The compounds with the highest odour unit values in all investigated wines were linalool, citronellol, geraniol, β-damascenone, β-ionone, isoamyl alcohol, 2-phenylethanol, ethyl hexanoate, ethyl octanoate, isoamyl acetate, ethyl acetate, and diethyl succinate. It has been shown that Muškat ruža porečki is an aromatic variety, producing wines with notable monoterpenol fraction, which are characterized by a typical varietal Muscat aroma with a dominant rose odour accompanied by red fruit nuances. Sensorially, longer maceration treatments improved odour and overall wine quality, together with the intensity and recognisability of varietal Muscat aroma, while short-term cryomaceration emerged as a preferable technique for the production of light rosé wines with pronounced Muscat aroma and low phenolic content. The presented maceration techniques were shown to be applicable for the production of different types of Muškat ruža porečki rosé and red wines. [ABSTRACT FROM AUTHOR]

Abstract: In this work, the harvest variability of the varietal composition of Fernão-Pires grape variety was evaluated using a dichloromethane liquid–liquid continuous extraction followed by GC-qMS of the free (F) and potential varietal components (PVC) from the musts across four harvests (1998, 1999, 2000, and 2002). This study showed that Fernão-Pires musts exhibited varietal volatile composition variability along the years. Based on the data obtained, using GC-qMS in tandem with PCA, relationships were established between the varietal volatile composition of the musts and the white wine aroma quality classification conferred by the official wine taster chamber. The results of the volatile analyses were consistent with the wine quality classification, indicating that the wine aroma quality is clearly associated with the musts free varietal volatile composition. On the other hand, the PVC fraction allowed the distinction of the musts according to the composition of potential aroma precursors. The proposed approach can provide information to winemakers concerning the winemaking methodologies that can be implemented to improve the varietal wine aroma quality. [ABSTRACT FROM AUTHOR]

Semi-synthetic must containing standard nutrients, a phenolic and aromatic fraction extracted from Albariño grapes and synthetic precursors of 3-mercaptohexanol (MOH) and 4-mercapto-4-pentan-2-one (MMP) were fermented with three different selected commercial S. cerevisiae yeasts. Wines were subjected to anoxic aging at 50 °C for 1, 2, 5 and 8 weeks, and their volatile composition was comprehensively determined by the analysis of 86 different aroma compounds using five different GC methods. Yeasts exert a strong influence on wine aroma throughout the whole aging period. Their effects extend beyond the well-known actions on yeast secondary metabolites, including the formation of little amounts of Strecker aldehydes or the formation of acids precursors of fruity esters, and on the enzymatic actions on the different grape aroma precursors. Additionally, yeasts influence wine aroma; first, by producing SO 2 which reacts with β-damascenone and increases Strecker aldehyde production in fermentation; second, by inducing the differential accumulation of Strecker aldehydes during anoxic aging; and third, by determining the stability of MOH, likely because of its reaction with vinylphenols or other yeast-related electrophiles. [Display omitted] • Yeast strain significantly affected wine aroma throughout aging. • Yeast-related little amounts of Strecker aldehydes found after fermentation. • Relevant increases with aging in three Strecker aldehydes in anoxic conditions. • Yeast-related differences in the stability of MOH during anoxic aging. • Relevant roles for yeast-related amino acids, dicarbonyls, SO 2 and vinylphenols. [ABSTRACT FROM AUTHOR]

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Abstract: Twenty-three monovarietal wines from 13 white and red grapes have been analysed by solid phase extraction–gas chromatography and solid phase micro-extraction–gas chromatography. The content of some varietal terpenic and fermentative volatile compounds was determined. The 13 studied varieties were characterised as well as the influence of winemaking practices like cold soaking and addition of glycosidase enzymes. Terpenic compounds showed a high variability between the 13 varieties which allows for its characterisation. The winemaking practices devoted to increase the aromatic properties of wines produced different results depending on the variety of grape. For example, cold soaking produced very different results if applied on Palomino fino variety or on Traminer variety, whereas for Viura variety few changes were found. Regarding the volatile compounds generated during the alcoholic fermentation, its relative amount is clearly related to the kind of fermentation process carried out, and particularly according to whether maceration of the solid parts has or has not been done during the process. In the case of vinification without maceration, there is a relative increase of fatty acids and their ethyl esters, whereas in vinification with maceration, the ethyl esters of lactic, acetic and succinic acids are the compounds that are relatively more abundant. Additionally, none of these compounds was affected by the techniques applied to increase varietal aroma, i.e. cold soaking, and addition of glycosidase enzymes showed very low influence in the levels of this kind of compounds. [Copyright &y& Elsevier]

Varietal compounds have been analyzed in wines prepared in the laboratory from four grape varieties grown in Spain. The possibilities for enhancing their aroma afforded by addition of glycosidase enzymes and steeping with the skin were studied. Both treatments increased substances responsible for varietal aroma in all wines, the effect being particularly significant for benzyl alcohol. [Copyright &y& Elsevier]

In recent years, many hop varieties with unique aromas, so-called "flavor hops", have been bred and grown. Here, we investigated the effect of late-harvested hops using three flavor hop varieties; Furano Beauty, Furano Magical, and Cascade. The sample hops were harvested at different days after flowering (DAF): DAF 45 (normal harvest), DAF 65, DAF 75, and DAF 85. We measured the volatile thiols in sample cones. The results indicated that 4-methyl-4-sulfanylpentane-2-one contents showed almost no change or a slightly decrease with a delay in harvest, whereas 3-sulfanyl-4-methylpentan-1-ol (3S4MP) content in late-harvested samples increased several fold in comparison with normal-harvested samples. Additionally, 3S4MP contents in the beers brewed with DAF 65 samples were several times higher than those using DAF 45 ones. From these results, we propose a new method to control 3S4MP content in hop cones by changing its harvest date.

• Vineyard calcium sprays shifted wine volatile profile. • Varietal and fermentative metabolites were affected by calcium. • γ-nonalactone was the most susceptible metabolite. • Acetates, alcohols and monoterpenols increased upon calcium treatment. • Calcium reduced volatile phenols, β-damascenone and benzaldehyde. Calcium supplements have increasingly been used at pre-harvest stages for improving fruit firmness, aiming at mitigating environmental stress. However, as recent studies demonstrated that calcium modifies the polyphenolic profile of grape berries, we hypothesize in this study that it also affects wine volatile profile. In a two-year study, grapevines cv. "Vinhão" were sprayed with 2% CaCl 2 throughout the fruiting season, and musts were prepared at a laboratory scale. Musts from calcium-treated fruits contained higher calcium levels and less anthocyanins. Increased calcium content did not affect the course of fermentation induced with a S. cerevisiae starter inoculum, but impacted the course of spontaneous fermentations carried out by endogenous berry microflora. Several compounds associated to varietal and fermentative aromas were largely influenced by the calcium treatment. For instance, volatile phenols decreased, together with β-damascenone, benzaldehyde and γ-nonalactone, while several acetates and alcohols increased. Principal component analysis showed that the volatile profile of control wines produced by spontaneous fermentation substantially differed between replicates, but calcium treatment lowered replicate variability. Volatile profiles were also influenced by the vintage and fermentation type. The shift in wine volatile profile upon calcium treatment may be relevant from an oenological perspective. [ABSTRACT FROM AUTHOR]

Hops are natural ingredients used to impart bitterness and flavor to beer. Recently, new varieties of hops have attracted global research attention. The Sorachi Ace variety, in particular, interests many craft brewers. This hop imparts characteristic varietal aromas, including woody, pine-like, citrus, dill-like, and lemongrass-like, to finished beers. Here, we investigated specific flavor compounds derived from Sorachi Ace using selectable one-dimensional or two-dimensional gas chromatography-olfactometry/mass spectrometry and head space-solid phase microextraction-gas chromatography-mass spectrometry. The results showed that a unique volatile compound, geranic acid, was present at a significant level only in the test beer brewed with the Sorachi Ace hop. Furthermore, sensory evaluation techniques revealed that geranic acid has very unique characteristics. This compound is not odor-active but functions as an enhancer for hop-derived terpenoids at subthreshold levels.