Aroma Profile Of Wines Research Articles

Qualitative and quantitative screening of the β-glucosidase activity in Saccharomyces cerevisiae and Saccharomyces uvarum strains isolated from refrigerated must.

In yeasts, β-glucosidase activity has been extensively described, especially in non-Saccharomyces species, while there is only little evidence of this activity in strains belonging to the Saccharomyces species. In winemaking, β-glucosidase plays essential roles in the hydrolysis of glyco-conjugated precursors and the release of active aromatic compounds. This study provides new insights into the β-glucosidase activity in strains belonging to Saccharomyces cerevisiae and Saccharomyces uvarum species, which are the most important strains in wine industry. Our results point out a marked enzymatic activity for the tested S. uvarum strains. These strains could be exploited for their potential ability to enhance the aroma profiles of wine. In addition, they could be potential sources for the commercial production of enzymes to be applied in winemaking.

Co-evolution as Tool for Diversifying Flavor and Aroma Profiles of Wines.

The products of microbial metabolism form an integral part of human industry and have been shaped by evolutionary processes, accidentally and deliberately, for thousands of years. In the production of wine, a great many flavor and aroma compounds are produced by yeast species and are the targets of research for commercial breeding programs. Here we demonstrate how co-evolution with multiple species can generate novel interactions through serial co-culture in grape juice. We find that after ~65 generations, co-evolved strains and strains evolved independently show significantly different growth aspects and exhibit significantly different metabolite profiles. We show significant impact of co-evolution of Candida glabrata and Pichia kudriavzevii on the production of metabolites that affect the flavor and aroma of experimental wines. While co-evolved strains do exhibit novel interactions that affect the reproductive success of interacting species, we found no evidence of cross-feeding behavior. Our findings yield promising avenues for developing commercial yeast strains by using co-evolution to diversify the metabolic output of target species without relying on genetic modification or breeding technologies. Such approaches open up exciting new possibilities for harnessing microbial co-evolution in areas of agriculture and food related research generally.

Screening of key odorants and anthocyanin compounds of cv. Okuzgozu (Vitis vinifera L.) red wines with a free run and pressed pomace using GC-MS-Olfactometry and LC-MS-MS.

The principal purpose of the present work is to characterize the aroma, aroma-active, and anthocyanin profiles of Okuzgozu wines and to observe the effect of the pomace pressing technique on these parameters. A total of 58 and 59 volatile compounds were identified and quantified in free-run juice wine (FRW) and pressed pomace wine (PW). Alcohols were found as the most dominant group among aroma compounds followed by esters and acids. However, among all these compounds, only 11 and 13 of them could be considered as key odorants in aromatic extracts of FRW and PW, respectively. According to GC-MS-O analysis, ethyl octanoate (fruity), phenyl ethyl acetate (fruity), and 2-phenyl ethanol (flowery) were found as the main contributors to the overall scent of both wines. Beyond the aroma profiles, anthocyanin contents of both types of wines were also investigated, and total 14 and 15 anthocyanins were identified and quantified in FRW and PW. Malvidin-3-glycoside and its acetyl and coumaroyl forms were identified as the dominant anthocyanins in both wines. It is worth noting the pressing application (2.0atm) led to an increase of some unpleasant notes in the aroma providing chemical, pharmacy, and fermented aromas in wine. On the other hand, the wines produced with pressed pomace presented higher amounts of anthocyanins.

Determination of Selected Aromas in Marquette and Frontenac Wine Using Headspace-SPME Coupled with GC-MS and Simultaneous Olfactometry

Understanding the aroma profile of wines made from cold climate grapes is needed to help winemakers produce quality aromatic wines. The current study aimed to add to the very limited knowledge of aroma-imparting compounds in wines made from the lesser-known Frontenac and Marquette cultivars. Headspace solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) with simultaneous olfactometry was used to identify and quantify selected, aroma-imparting volatile organic compounds (VOC) in wines made from grapes harvested at two sugar levels (22° Brix and 24° Brix). Aroma-imparting compounds were determined by aroma dilution analysis (ADA). Odor activity values (OAV) were also used to aid the selection of aroma-imparting compounds. Principal component analysis and hierarchical clustering analysis indicated that VOCs in wines produced from both sugar levels of Marquette grapes are similar to each other, and more similar to wines produced from Frontenac grapes harvested at 24° Brix. Selected key aroma compounds in Frontenac and Marquette wines were ethyl hexanoate, ethyl isobutyrate, ethyl octanoate, and ethyl butyrate. OAVs >1000 were reported for three aroma compounds that impart fruity aromas to the wines. This study provides evidence that aroma profiles in Frontenac wines can be influenced by timing of harvesting the berries at different Brix. Future research should focus on whether this is because of berry development or accumulation of aroma precursors and sugar due to late summer dehydration. Simultaneous chemical and sensory analyses can be useful for the understanding development of aroma profile perceptions for wines produced from cold-climate grapes.

Investigation of ‘stone fruit’ aroma in Chardonnay, Viognier and botrytis Semillon wines

Despite numerous studies, the identity of the compounds that are responsible for ‘stone fruit’ aroma in wine has not been conclusively established. This study focussed on wine varieties that often display peach and apricot characters, such as Chardonnay, Viognier and botrytis-affected sweet Semillon wines. Wines with high and low ‘stone fruit’ aroma were evaluated by gas chromatography-olfactometry-mass spectrometry (GC-O-MS) using extracts representative of the aroma of the wine in a glass. No aroma-active zone was described as ‘stone fruit’ aroma across all three wine varietals. However, for the individual varieties, terpenes, such as linalool and geraniol, in the Viognier wines, several esters in the Chardonnay wines, and γ-nonalactone in the botrytis Semillon were associated with ‘stone fruit’ aroma. Notably, this is the first study assessing the aroma profile of Viognier wine by GC-O. In addition, an extension study of Viognier grape monoterpene profiles clarified its classification as an aromatic variety.

Molecular and Phenotypic Characterization of Metschnikowia pulcherrima Strains from Douro Wine Region

Some non-Saccharomyces yeasts, including Metschnikowia pulcherrima, have been proposed as selected starters due to their contribution for the overall aroma and chemical profiles of wines. In this work, we aimed to evaluate the genetic and phenotypic diversity of Metschnikowia pulcherrima strains isolated from different locations of Douro Wine Region, and to explore their potential as co-adjuncts of S. cerevisiae in alcoholic fermentation. For that purpose, a set of 64 M. pulcherrima isolates were used. Polymerase chain reaction (PCR) fingerprinting with M13 primers demonstrated to be an efficient tool in intraspecific discrimination of M. pulcherrima strains. No significant associations were found between genotypic profiles and either geographical origin or winery. The isolates were screened for their stress resistance ability (ethanol, SO2, chitosan, copper, H2O2, and Grape Juice Medium), aroma-related activities (resistance to 5, 5′, 5′′-trifluor-d, l-leucine and cerulenin and β-glycosidase, β-lyase and sulfite-reductase activities) as well as other relevant technological proprieties (protease activity and biogenic amines production). M. pulcherrima response to the different enological traits evaluated was greatly strain-dependent. The most discriminant features were the ability of the strains to grow in Grape-Juice Medium (GJM) and sulfite-reductase, and their β-lyase and protease activities. The enological potential of a selected M. pulcherrima strain in mixed-culture with S. cerevisiae was also assessed in natural grape-juice of a local variety, under two nitrogen regimes. M. pulcherrima proved to be promising for future industrial application as a co-starter, lowering ethanol, acetic acid and, reported here for the first time, lowering hydrogen sulfide levels in the wines.

Comparison on evolution of volatile compounds and aroma attributes in different pH-adjusted fermented bog bilberry syrup wines during bottle-aging period

Bottle-aging improves the overall aroma of wine and different pH fermentation conditions can alter the evolution pattern of volatiles in wine during bottle-aging. In this study, the evolution of volatiles and aromas was investigated in different pH fermented bog bilberry syrup wines during a 6-month bottle-aging. Results showed that a total of 93 volatile compounds were found in bog bilberry syrup wine after fermentation. During bottle-aging, these volatiles exhibited 8 evolution patterns, and pH adjustment affected the evolution of esters, higher alcohols and acids. Eleven volatiles contributed their flavor scents to bog bilberry syrup wine overall aroma. Fruity, fatty and solvent scents were the major aromas, and pH adjustment induced an alteration on the aroma attributes during bottle-aging. Principal component analysis indicated that bottle-aging process segregated the sensory similarity of bog bilberry syrup wines through altering their aroma attributes. Low pH wine was separated from middle and high pH wines after 6 months of bottle-aging due to its high level of solvent and balsamic aromas. This indicated that pH adjustment resulted in a pattern difference on the evolution of volatiles during bottle-aging, which altered aroma profile of bog bilberry syrup wine.

Sensory Characterization of Wines Obtained by Blending Cencibel Grapes and Minority Grape Varieties Cultivated in La Mancha Region

The objective of this work was measuring the influence of co-winemaking technique on sensory profile of young red wines made from Rojal, Moravia Dulce, and Tortosí grape varieties cultivated in La Mancha region (Spain) using aroma sensory profile. Sensory aroma profile was evaluated by a panel of 15 experienced wine testers with a previous training. The sensory aroma profiles of monovarietal wines from Rojal, Tortosí, and Moravia Dulce were researched and the effect of blending these grape varieties with Cencibel grapes on sensory characteristics of wines was studied. Co-winemaking wines were elaborated by mixing of (a) Cencibel (50%) + Rojal (50%); (b) Cencibel (50%) + Tortosí (50%); and (c) Cencibel (50%) + Moravia Dulce (50%). The blending of these grape varieties increased the principal aroma attributes of monovarietal wines and, in general, co-winemaking wines exhibited a greater complexity of aroma profile.

Employing oxygen pulses to modulate Lachancea thermotolerans–Saccharomyces cerevisiae Chardonnay fermentations

Oxygen is sometimes deliberately introduced in winemaking at various stages to enhance yeast biomass formation and prevent stuck fermentation. However, there is limited information on how such interventions affect the dynamics of yeast populations. Our previous study in synthetic grape juice showed that oxygen supply enhances the persistence of Lachancea thermotolerans, Torulaspora delbrueckii and Metschnikowia pulcherrima. The three non-Saccharomyces yeasts showed differences in growth as a function of oxygen. The present study focused on evaluating the influence of short oxygen pulses on population dynamics and the aroma profile of Chardonnay wine inoculated with L. thermotolerans and Saccharomyces cerevisiae. The results confirmed a positive effect of oxygen on the relative performance of L. thermotolerans. The mixed culture fermentation with L. thermotolerans with S. cerevisiae developed a distinct aroma profile when compared to monoculture S. cerevisiae. Specifically, a high concentration of esters, medium chain fatty acids and higher alcohols was detected in the mixed culture fermentation. The data also showed that the longer persistence of L. thermotolerans due to addition of oxygen pulses influenced the formation of major volatile compounds such as ethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl caprylate, ethyl caprate, ethyl-3-hydroxybutanoate, ethyl phenylacetate, propanol, isobutanol, butanol, isoamyl alcohol, hexanol, isobutyric acid, butyric acid, iso-valeric acid, hexanoic acid, octanoic acid, and decanoic acid.

Analysis of Volatile Components of Varietal English Wines Using Stir Bar Sorptive Extraction/Gas Chromatography-Mass Spectrometry

Aroma is an important property of wine and it can be influenced significantly by enological practices. The aim of this work was, by use of stir bar sorptive extraction/gas chromatography-mass spectrometry (SBSE/GC-MS), to compare semi-quantitative concentrations of the volatile constituents of stainless steel tank-fermented/matured Huxelrebe, Ortega, Schönburger and Siegerrebe varietal wines from a commercial English vineyard, with corresponding wines produced by oak cask (‘barrel’) fermentation/maturation. Aroma profiles of tank and barrel wines were different, with more volatiles detected and net concentrations being higher in barrel wines. Long chain ethyl carboxylate esters were generally more abundant in barrel wines, whereas acetate esters were generally more prominent in tank wines. By conducting a short (~7 month) maturation period in secondhand (third or fourth fill) casks, it was possible to make wines with more complex aromas, but without obvious oak aroma.

Effect of the addition of branched-chain amino acids to non-limited nitrogen synthetic grape must on volatile compounds and global gene expression during alcoholic fermentation

Background and Aims The concentration and composition of nitrogen (N) in must is critical to yeast fermentation and aroma profiles in wine. We investigated the effect of adding branched-chain amino acids (BCAAs, including l-valine, l-leucine and l-isoleucine) to a non-limited N medium on the formation of aromatic compounds and on gene expression patterns of the wine yeast Saccharomyces cerevisiae. Methods and Results A synthetic N-sufficient must was supplemented with BCAAs and fermented with S. cerevisiae. The fermentation kinetics, aroma characteristics and yeast global gene expression in wine with addition of BCAAs were compared with that of the Control. Addition of BCAAs improved yeast growth and fermentation activity, increased the production of higher alcohols, medium-chain fatty acids and their corresponding esters (82, 34 and 49% increment compared to that of the Control, respectively). The comparative transcriptomic analysis revealed that 25 genes varied in their expression during fermentation with added BCAAs relative to that of the Control, which are mainly involved in yeast growth and proliferation (GIP1, DIT2, RCK1, SPO1 and MEK1) and transport of amino acids (GAP1). Conclusions An increase in BCAA transport ability and in yeast population is the main reason for achieving an increased concentration of volatile aroma compounds in wine with addition of BCAAs. Significance of the Study Our results suggest that adding BCAAs into N-sufficient must is still an efficient way to adjust wine's aromatic composition and improve aroma complexity.

Additions of Glutathione or Specific Glutathione-rich Dry inactivated Yeast Preparation (DYP) to Sauvignon blanc Must: Effect on Wine Chemical and Sensory Composition

Although the addition of pure glutathione (GSH) is not allowed under current regulations, the concentration of this compound can be increased in wine through the addition of glutathione-enriched dry yeast preparations (DYP). These preparations have been observed to have antioxidant properties and could thus influence wine aroma and sensory characteristics. The main aim of this study was to investigate the effect of DYP and GSH juice additions on the sensory and chemical composition of Sauvignon blanc wine. Four juice additions were performed and compared against a control treatment: 5.5 mg/L of GSH; 0.4 g/L of DYP; 80 mg/L of GSH; 0.4 g/L of DYP plus 80 mg/L of GSH. After three months of bottling, the volatile and sensorial composition was investigated. The addition of DYP preparations to must increased the concentration of certain wine volatile compounds, with increased attributes of riper tropical fruit aromas, which was not always observed with the GSH additions. The addition of DYP influenced the concentrations of some volatile compounds, which modified the white wine aroma. The release of compounds other than GSH by the yeast products is proposed as the reason for these changes. The results observed in this study can assist winemakers to modify the aroma profile of Sauvignon blanc wines.

Development of an Automated Method for Selected Aromas of Red Wines from Cold-Hardy Grapes Using Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry-Olfactometry

The aroma profile of red wine is complex and research focusing on aroma compounds and their links to viticultural and enological practices is needed. Current research is limited to wines made from cold-hardy cultivars (interspecific hybrids of vinifera and native N. American grapes). The objective of this research was to develop a fully automated solid phase microextraction (SPME) method, using tandem gas chromatography-mass spectrometry (GC-MS)-olfactometry for the simultaneous chemical and sensory analysis of volatile/semi-volatile compounds and aroma in cold-hardy red wines. Specifically, the effects of SPME coating selection, extraction time, extraction temperature, incubation time, sample volume, desorption time, and salt addition were studied. The developed method was used to determine the aroma profiles of seven selected red wines originating from four different cold-hardy grape cultivars. Thirty-six aroma compounds were identified from Maréchal Foch, St. Croix, Frontenac, Vincent, and a Maréchal Foch/Frontenac blend. Among these 36 aroma compounds, isoamyl alcohol, ethyl caproate, benzeneethanol, ethyl decanoate, and ethyl caproate are the top five most abundant aroma compounds. Olfactometry helps to identify compounds not identified by MS. The presented method can be useful for grape growers and wine makers for the screening of aroma compounds in a wide variety of wines and can be used to balance desired wine aroma characteristics.

Aroma profile of malbec red wines from La Mancha region: Chemical and sensory characterization

The aroma of La Mancha Malbec red wines over four consecutive vintages was characterized by chemical and sensory analysis. Solid phase extraction (SPE) and gas chromatography–mass spectrometry (GC–MS) were used to isolate and analyze free volatile compounds. Quantitative Descriptive Sensory Analysis (QDA) was carried out to characterize the sensory aroma profile. A total of 79 free volatile compounds were identified and quantified in the wines over these four vintages. Volatile aroma compounds were classified into seven aromatic series and their odour activity values were calculated in order to determine the aroma impact compounds in these wines. The aroma sensory profile of these wines was characterized by red fruit, fresh, prune, liquorice, clove, caramel, leather, tobacco and coffee aromas. This study provides a complete aroma characterization of La Mancha Malbec red wines and it is proposed that these wines can be considered as an alternative to wines from traditional grape varieties of this region.

Evaluation of aroma enhancement for "Ecolly" dry white wines by mixed inoculation of selected Rhodotorula mucilaginosa and Saccharomyces cerevisiae.

To improve the aroma profile of Ecolly dry white wine, the simultaneous and sequential inoculations of selected Rhodotorula mucilaginosa and Saccharomyces cerevisiae were performed in wine making of this work. The two yeasts were mixed in various ratios for making the mixed inoculum. The amount of volatiles and aroma characteristics were determined the following year. Mixed fermentation improved both the varietal and fermentative aroma compound composition, especially that of (Z)-3-hexene-1-ol, nerol oxide, certain acetates and ethyls group compounds. Citrus, sweet fruit, acid fruit, berry, and floral aroma traits were enhanced by mixed fermentation; however, an animal note was introduced upon using higher amounts of R. mucilaginosa. Aroma traits were regressed with volatiles as observed by the partial least-square regression method. Analysis of correlation coefficients revealed that the aroma traits were the multiple interactions of volatile compounds, with the fermentative volatiles having more impact on aroma than varietal compounds.

Detection with flash gas chromatography electronic nose of the general influences of glutathione, ascorbic acid, tannin and carbon dioxide treatments on the volatile profiles of white wines of feteasca regala

The present work aimed to determine some of the influences of the treatments with glutathione (GSH), ascorbic acid (AA), catechinic tannin (T) and carbon dioxide (CO2 ) during winemaking or bottling on the volatile profiles of white wines of Feteasca Regala. The study is based on the use of a flash gas chromatography electronic nose, which is able to discriminate various clusters of wine samples prepared with various combinations of antioxidants. The treatments that induce enough differences in the volatile profiles of the wine that the electronic nose is able to discriminate are likely to be discriminated also by the consumers. When the electronic nose does not discriminate the clusters of samples with certain treatments it is very likely that those treatments are not sufficient to induce a practically important difference in the aromatic profile of wines. The main detectable influences of the antioxidant treatments are presented and discussed. The treatment of musts with AA (50 mg/l) clearly influences the volatile profile of the wines, reducing their aromatic complexity. The treatment during bottling with catechinic tannin (20 mg/l) does not seem to have an important influence of the profile of the wines produced with the addition of AA and or GSH. The addition of carbon dioxide during bottling does not show much influence one year after bottling, but it shows that in the samples most prone to oxidation, a difference is present. The CO2 treated wines belonging to the cluster of wines treated with 40 mg/l GSH and 50 mg/l AA have distinct profiles, different from those not protected and closer to the clusters of the less oxidised wines. The treatment of musts with GSH shows clear influences at the dose of 40 mg/l, but for the lower dose of 20 mg/l GSH in Feteasca regala wines it is difficult to identify differences compared to the wines included in the cluster of samples not treated with GSH. This finding is particularly relevant as the dose of 20 mg/l GSH is the maximum allowed at present to be added in must and wines.

Approaches to outline the aromatic profile of Kyoho wines from South Korea

Kyoho cultivar is a hybrid of V. vinifera and V. labrusca and is one of the major varieties cultivate in South Korea. Kyoho grapes are characterized for their intense grape flavor and sour attributes. Korean climatic conditions are different from worldwide wine producing countries. The summer season is hot and dominated by heavy rains. Wines from Kyoho grapes are distinct for their intense grape flavor and the key odors that characterize the wines are aromas of caramel and strawberry notes. The past few years efforts are put to improve the quality and to advance the potential of the domestic wines. The objective of the present study is to provide insight to the main aromatic compounds that form the aroma profile of Kyoho wines. For this aim, Gas Chromatography was coupled with Mass Spectrometry for the separation and identification of the compounds. Analysis allowed to identify the volatile compounds that form the aroma of the wine and to detect the key odors of its characteristic aroma. (2,5-dimethyl-4-hydroxy-3(2H)-furanone) Furaneol® , which is associated with caramel-like flavor, was one of the compounds that were detected along with ((3R)-hydroxy-4,4-dimethyloxolan-2-one) pantolactone.

Microbial Strains as a Key Role Played on Aroma Profiles of Mao-Berry Fruit Wine

Microbial Strains as a Key Role Played on Aroma Profiles of Mao-Berry Fruit Wine

Pre-fermentative cold maceration, saignée, and various thermal treatments as options for modulating volatile aroma and phenol profiles of red wine.

The effects of six maceration treatments on volatile aroma and phenol composition of Teran red wine were studied: standard maceration (control C), cold pre-fermentation maceration (CPM), saignée (S), pre-fermentation heating with extended maceration (PHT) or juice fermentation (PHP), and post-fermentation heating (POH). PHP wine contained the highest amounts of esters, fatty acids and anthocyanins, and the lowest content of other phenols. Alternative treatments decreased higher alcohols in relation to control C. CPM treatment lowered the extraction of seed tannins, exhibited the highest acetaldehyde, ethyl acetate and C6-compounds levels, and had increased ester levels in relation to control C. POH wine contained the highest concentration of total phenols, flavonoids, monomeric, oligomeric and polymeric flavanols, and color intensity and hue. S and PHT wines contained lower amount of total phenols, but higher than in C and CPM wines. The calculated Odor Activity Values were used to establish significant differences between the treatments.

Impact of oxygenation on the performance of three non-Saccharomyces yeasts in co-fermentation with Saccharomyces cerevisiae.

The sequential or co-inoculation of grape must with non-Saccharomyces yeast species and Saccharomyces cerevisiae wine yeast strains has recently become a common practice in winemaking. The procedure intends to enhance unique aroma and flavor profiles of wine. The extent of the impact of non-Saccharomyces strains depends on their ability to produce biomass and to remain metabolically active for a sufficiently long period. However, mixed-culture wine fermentations tend to become rapidly dominated by S. cerevisiae, reducing or eliminating the non-Saccharomyces yeast contribution. For an efficient application of these yeasts, it is therefore essential to understand the environmental factors that modulate the population dynamics of such ecosystems. Several environmental parameters have been shown to influence population dynamics, but their specific effect remains largely uncharacterized. In this study, the population dynamics in co-fermentations of S. cerevisiae and three non-Saccharomyces yeast species: Torulaspora delbrueckii, Lachancea thermotolerans, and Metschnikowia pulcherrima, was investigated as a function of oxygen availability. In all cases, oxygen availability strongly influenced population dynamics, but clear species-dependent differences were observed. Our data show that L. thermotolerans required the least oxygen, followed by T. delbrueckii and M. pulcherrima. Distinct species-specific chemical volatile profiles correlated in all cases with increased persistence of non-Saccharomyces yeasts, in particular increases in some higher alcohols and medium chain fatty acids. The results highlight the role of oxygen in regulating the succession of yeasts during wine fermentations and suggests that more stringent aeration strategies would be necessary to support the persistence of non-Saccharomyces yeasts in real must fermentations.