Changes in aromatic characteristics of Loureiro and Alvarinho wines during maturation

Sequential Fermentation in Red Wine cv. Babić Production: The Influence of Torulaspora delbrueckii and Lachancea thermotolerans Yeasts on the Aromatic and Sensory Profile

This research aimed to analyze the impact of two different non-Saccharomyces yeast species on the aromatic profile of red wines made from the cv. Babić (Vitis vinifera L.) red grape variety. The grapes were obtained from two positions in the Middle and South of Dalmatia. This study compared a control treatment with the Saccharomyces cerevisiae (Sc) strain as a type of sequential inoculation treatment with Lachancea thermotolerans (Lt x Sc) and Torulaspora delbrueckii (Td x Sc). The focus was on the basic wine parameters and volatile aromatic compound concentrations determined using the SPME-Arrow-GC/MS method. The results revealed significant differences in cis-linalool oxide, geraniol, neric acid, and nerol, which contribute to the sensory profile with floral and rose-like aromas; some ethyl esters, such as ethyl furoate, ethyl hexanoate, ethyl lactate, ethyl 2-hydroxy-3-methylbutanoate, ethyl 3-hydroxy butanoate, diethyl glutarate, and diethyl succinate, contribute to the aromatic profile with fruity, buttery, overripe, or aging aromas. A sensory evaluation of wines confirmed that Td x Sc treatments exhibited particularly positive aromatic properties together with a more intense fullness, harmony, aftertaste, and overall impression.

Volatile profile of two monovarietal white wines under different antioxidant environments during storage in bottle

The volatile organic compounds (VOCs) formed during winemaking can be modulated by several additives, namely by the use of sulphur dioxide (SO2) which has been well-accepted on winemaking as a preservative agent. However, some drawbacks associated with SO2 wine application led to the need to reduce or replace its use. In this work, VOCs profile after storage in bottle under different antioxidant conditions of two Portuguese monovarietal wines (‘Arinto’ and ‘Síria’) was studied. Wines were obtained by different winemaking environments (0, 50, 100 mg/L of SO2 and 100 mg/L ascorbic acid for ‘Síria’ and 15, 30, 45 mg/L of SO2 and 100 mg/L of ascorbic acid for ‘Arinto’ both with and without bentonite). After alcoholic fermentation, a second SO2 treatment was applied: 0 and 60 mg/L of SO2 to ‘Arinto’ wines and 30 and 60 mg/L of SO2 to ‘Síria’ wines. Wines were kept over lees for three months, bottled and analysed after three months in bottle. The VOCs present were analysed by HS-SPME-GC/MS six months after fermentation. The maturation conditions did not influence the evolution of free and total SO2. Regarding the VOCs profile evolution, the ANOVA analysis showed that esters are the most important group, presenting significant differences among samples. Through the PCA analysis, using wines after fermentation as reference, 74.13 % and 54.92 % of the variation were explained by the first two principal components for ‘Arinto’ and ‘Síria’, respectively. VOCs profile evolution of wines seems to be mainly influenced by the fermentation conditions.

Wine Storage at Cellar vs. Room Conditions: Changes in the Aroma Composition of Riesling Wine

Storage temperature is one of the most important factors affecting wine aging. Along with bottling parameters (type of stopper, SO₂ level and dissolved O₂ in wine), they determine how fast wine will evolve, reach its optimum and decline in sensory quality. At the same time, lowering of the SO₂ level in wine has been a hot topic in recent years. In the current work, we investigated how Riesling wine evolved on the molecular level in warm (~25 °C) and cool (~15 °C) conditions depending on the SO₂ level in the wine (low, medium and high), flushing of the bottle's headspace with CO₂ and three types of stoppers (Diam 30, Diam 30 origin and Diam 5) with different OIR levels (0.8-1.3 mg) and OTR levels (0.3-0.4 mg/year). It was demonstrated that the evolution of primary and secondary aromas, wine color and low molecular weight sulfur compounds (LMWSCs) during the two years of aging mainly depended on the storage temperature. Variation in the SO₂ level and CO₂ in the headspace affected mostly certain LMWSCs (H₂S, MeSH) and β-damascenone. New aspects of C₁₃-norisprenoids and monoterpenoids behavior in Riesling wine with different levels of SO₂ and O₂ were discussed. All three types of stoppers showed very close wine preservation properties during the two years of storage. The sensory analysis revealed that, after only six months, the warm stored wines with a low SO₂ level were more oxidized and different from the samples with medium and high SO₂ levels. A similar tendency was also observed for the cool stored samples.

Classification of Botrytized Wines Based on Producing Technology Using Flow-Modulated Comprehensive Two-Dimensional Gas Chromatography

The enantiomeric ratio of chiral compounds is known as a useful tool to estimate wine quality as well as observe an influence of wine-producing technology. The incorporation of flow-modulated comprehensive two-dimensional gas chromatography in this type of analysis provides a possibility to improve the quality of results due to the enhancement of separation capacity and resolution. In this study, flow-modulated comprehensive two-dimensional gas chromatography was incorporated in enantioselective analysis to determine the influence of winemaking technology on specific features of botrytized wines. The samples included Tokaj essences (high-sugar wines), Tokaj botrytized wines and varietal wines (Furmint, Muscat Lunel, Lipovina) and wines maturated on grape peels. The obtained data was processed with hierarchic cluster analysis to reveal variations in composition and assess classification ability for botrytized wines. A significant difference between the samples was observed for the enantiomeric distribution of ethyl lactate and presence of monoterpene alcohols. The varietal wines were successfully separated from the other types, which showed more similar results and could be divided with additional parameters. We observed a correlation between the botrytized wines and the varietal wines fermented with grape skins. As to the essences produced from juice of botrytized grapes, the results were quite similar to those of the botrytized wines, even though monoterpenes were not detected in the extracts.

Volatile Profile Characterization of Croatian Commercial Sparkling Wines

Commercial sparkling wine production represents a relatively low but important part of the Croatian wine production, especially in the Zagreb county. This study presents the results of volatile aroma compounds profile and organic acid composition of commercial sparkling wine samples from three vine-growing regions in Zagreb county. In total, 174 volatile aroma compounds were identified, separated between their chemical classes (aldehydes, higher alcohols, volatile phenols, terpenes, C13-norisoprenoids, lactones, esters, fatty acids, sulfur compounds, other compounds, other alcohols). Higher alcohols such as phenylethyl and isoamyl alcohol as well as 2-methyl-1-butanol, and esters such as diethyl succinate, ethyl hydrogensuccinate, and ethyl lactate had the strongest impact on the volatile compounds profile of Zagreb county sparkling wine. The presence of diethyl glutarate and diethyl malonate, compounds whose concentrations are influenced by yeast autolysis or caused by chemical esterification during the ageing process, was also noted. The influence of every single volatile aroma compound was evaluated by discriminant analysis using forward stepwise model. The volatile profiles of traditional sparkling wines from Croatia were presented for the first time. It is hoped the results will contribute to better understanding the quality potential and to evaluate possible differences on the bases of detected aroma concentrations and multivariate analysis.

Validation of a LLME/GC-MS Methodology for Quantification of Volatile Compounds in Fermented Beverages

Knowledge of composition of beverages volatile fraction is essential for understanding their sensory attributes. Analysis of volatile compounds predominantly resorts to gas chromatography coupled with mass spectrometry (GC-MS). Often a previous concentration step is required to quantify compounds found at low concentrations. This work presents a liquid-liquid microextraction method combined with GC-MS (LLME/GC-MS) for the analysis of compounds in fermented beverages and spirits. The method was validated for a set of compounds typically found in fermented beverages comprising alcohols, esters, volatile phenols, and monoterpenic alcohols. The key requirements for validity were observed, namely linearity, sensitivity in the studied range, accuracy, and precision within the required parameters. Robustness of the method was also evaluated with satisfactory results. Thus, the proposed LLME/GC-MS method may be a useful tool for the analysis of several fermented beverages, which is easily implementable in a laboratory equipped with a GC-MS.

Modifications of Phenolic Compounds, Biogenic Amines, and Volatile Compounds in Cabernet Gernishct Wine through Malolactic Fermentation by Lactobacillus plantarum and Oenococcus oeni

Malolactic fermentation is a vital red wine-making process to enhance the sensory quality. The objective of this study is to elucidate the starter cultures’ role in modifying phenolic compounds, biogenic amines, and volatile compounds after red wine malolactic fermentation. We initiated the malolactic fermentation in Cabernet Gernishct wine by using two Oenococcus oeni and two Lactobacillus plantarum strains. Results showed that after malolactic fermentation, wines experienced a content decrease of total flavanols and total flavonols, accompanied by the accumulation of phenolic acids. The Lactobacillus plantarum strains, compared to Oenococcus oeni, exhibited a prevention against the accumulation of biogenic amines. The malolactic fermentation increased the total esters and modified the aromatic features compared to the unfermented wine. The Lactobacillus plantarum strains retained more aromas than the Oenococcus oeni strains did. Principal component analysis revealed that different strains could distinctly alter the wine characteristics being investigated in this study. These indicated that Lactobacillus plantarum could serve as a better alternative starter for conducting red wine malolactic fermentation.

Effect of Vertical Shoot-Positioned, Scott-Henry, Geneva Double-Curtain, Arch-Cane, and Parral Training Systems on the Volatile Composition of Albariño Wines

Viticultural practices influence both grape and wine quality. The influence of training systems on volatile composition was investigated for Albariño wine from Rías Baixas AOC in Northwest Spain. The odoriferous contribution of the compounds to the wine aroma was also studied. Volatile compounds belonging to ten groups (alcohols, C₆-compounds, ethyl esters, acetates, terpenols, C₁₃-norisoprenoids, volatile phenols, volatile fatty acids, lactones and carbonyl compounds) were determined in Albariño wines from different training systems, Vertical Shoot-Positioned (VSP), Scott-Henry (SH), Geneva Double-Curtain (GDC), Arch-Cane (AC), and Parral (P) during 2010 and 2011 vintages. Wines from GDC showed the highest total volatile composition with the highest concentrations of alcohols, ethyl esters, fatty acids, and lactones families. However, the highest levels of terpenes and C₁₃-norisoprenoids were quantified in the SH system. A fruitier aroma was observed in Albariño wines from GDC when odor activity values were calculated.

Harvest date effects on aroma compounds in aged Riesling icewines

BACKGROUND

Riesling icewine is an important product of the Ontario wine industry. The objective of this study was to characterize concentrations in aroma compounds in aged icewines associated with three harvest dates (H1, H2, H3) using stir bar sorptive extraction-gas chromatography-mass spectrometry and to make inferences, where appropriate, with respect to their roles in potential wine quality.

RESULTS

Delaying harvest decreased concentrations of many odorants, but increased many critical odor-active compounds; e.g. 1-octen-3-ol, ethyl benzoate, ethyl octanoate, cis-rose oxide, and β-ionone. H1 wines had higher concentrations of four aldehydes, three alcohols, nine esters, seven terpenes, γ-nonalactone, p-vinylguaiacol, β-damascenone, and 2-furanmethanol. However, many of these compounds, with some exceptions, have relatively high odor thresholds. Fourteen compounds were above their odor thresholds, including decanal, 1-octen-3-ol, phenylethyl alcohol, four ethyl esters, cis-rose oxide, linalool, γ-nonalactone, p-vinylguaiacol, ethyl cinnamate, β-damascenone, and 1,1,6-trimethyl-1,2-dihydronaphthalene. H3 wines contained higher concentrations of highly odor-active compounds, e.g. 1-octen-3-ol, cis-rose oxide, and β-ionone. Only phenylethyl alcohol [H3 odor activity value (OAV) = 0.33 (honey, spice, rose)] and linalool [H3 OAV = 0.92 (floral, lavender)] had H3 OAVs < 1.

CONCLUSIONS

Early harvest increased many esters and aliphatic compounds, but delayed harvest appeared to substantially increase concentrations of several highly odor-active compounds. © 2016 Society of Chemical Industry.

Use of Schizosaccharomyces pombe and Torulaspora delbrueckii strains in mixed and sequential fermentations to improve red wine sensory quality

One of the main opportunities in the use of non-Saccharomyces yeasts is its great intraspecific variability in relation to the synthesis of secondary products of fermentation. Thus, mixed or sequential fermentation with non-Saccharomyces can increase the synthesis of certain metabolites that are important for colour stability, such as acetaldehyde and pyruvic acid (vitisin precursors) or vinylphenols (vinylphenolic pyranoanthocyanin precursors). Furthermore, the selection and use of non-Saccharomyces yeast strains with good yields in the production of certain volatile compounds (ethyl lactate, 2,3-butanediol, 2-phenylethyl acetate), with limited formation of higher alcohols, is a way to improve the aromatic profile of red wine. The main aim of this work was to evaluate the influence of sequential and mixed fermentations with Schizosaccharomyces pombe and Torulaspora delbrueckii strains on red wine's sensory quality. Anthocyanins and aromatic profiles, as well as glycerol and organic acid content, were analysed in the red wines obtained. Results show that, in general, mixed fermentations can promote an increment in polyols synthesis, while sequential fermentations can enhance the herbaceous aroma. Moreover, the use of T. delbrueckii in mixed fermentations allowed an increase to the fruity character of red wine. The use of S. pombe in sequential fermentations increased the stability of the colouring matter by favouring vitisins and vinylphenolic pyranoanthocyanin formation.

Volatile profile of Madeira wines submitted to traditional accelerated ageing

The evolution of monovarietal fortified Madeira wines forced-aged by traditional thermal processing (estufagem) were studied in terms of volatiles. SPE extracts were analysed by GC-MS before and after heating at 45 °C for 3 months (standard) and at 70 °C for 1 month (overheating). One hundred and ninety volatile compounds were identified, 53 of which were only encountered in baked wines. Most chemical families increased after standard heating, especially furans and esters, up to 61 and 3-fold, respectively. On the contrary, alcohols, acetates and fatty acids decreased after heating. Varietal aromas, such as Malvasia's monoterpenic alcohols were not detected after baking. The accelerated ageing favoured the development of some volatiles previously reported as typical aromas of finest Madeira wines, particularly phenylacetaldeyde, β-damascenone and 5-ethoxymethylfurfural. Additionally, ethyl butyrate, ethyl 2-methylbutyrate, ethyl caproate, ethyl isovalerate, guaiacol, 5-hydroxymethylfurfural and γ-decalactone were also found as potential contributors to the global aroma of baked wines.

Wine metabolomics: objective measures of sensory properties of semillon from GC-MS profiles

The contribution of volatile aroma compounds to the overall composition and sensory perception of wine is well recognized. The classical targeted measurement of volatile compounds in wine using GC-MS is laborious and only a limited number of compounds can be quantified at any time. Application of an automated multivariate curve resolution technique to nontargeted GC-MS analysis of wine makes it possible to detect several hundred compounds within a single analytical run. Hunter Valley Semillon (HVS) is recognized as a world class wine with a range of styles. Subtle characters reliant upon the development of bottle maturation characteristics are a feature of highly esteemed HVS. In this investigation a metabolomic approach to wine analysis, using multivariate curve resolution techniques applied to GC-MS profiles coupled with full descriptive sensory analysis, was used to determine the objective composition of various styles of HVS. Over 250 GC-MS peaks were extracted from the wine profiles. Sensory scores were analyzed using PARAFAC prior to development of predictive models of sensory features from the extracted GC-MS peak table using PLS regression. Good predictive models of the sensorial attributes honey, toast, orange marmalade, and sweetness, the defining traits for HVS, could be determined from the extracted peak tables. Compound identification for these rated attributes indicated the importance of a range of ethyl esters, aliphatic alcohols and acids, ketones, aldehydes, furanic derivatives, and norisoprenoids in the development of HVS and styles. The development of automated metabolomic data analysis of GC-MS profiles of wines will assist in the development of wine styles for specific consumer segments and enhance understanding of production processes on the ultimate sensory profiles of the product.

Aroma chemical composition of red wines from different price categories and its relationship to quality

The aroma chemical composition of three sets of Spanish red wines belonging to three different price categories was studied by using an array of gas chromatographic methods. Significant differences were found in the levels of 72 aroma compounds. Expensive wines are richest in wood-related compounds, ethyl phenols, cysteinil-derived mercaptans, volatile sulfur compounds, ethyl esters of branched acids, methional, and phenylacetaldehyde and are poorest in linear and branched fatty acids, fusel alcohols, terpenols, norisoprenoids, fusel alcohol acetates, and ethyl esters of the linear fatty acids; inexpensive wines show exactly the opposite profile, being richest in E-2-nonenal, E-2-hexenal, Z-3-hexenol, acetoin, and ethyl lactate. Satisfactory models relating quality to odorant composition could be built exclusively for expensive and medium-price wines but not for the lower-price sample set in which in-mouth attributes had to be included. The models for quality reveal a common structure, but they are characteristic of a given sample set.

Geographical origin of Sauvignon Blanc wines predicted by mass spectrometry and metal oxide based electronic nose

Analysis of 34 Sauvignon Blanc wine samples from three different countries and six regions was performed by gas chromatography-mass spectrometry (GC-MS). Linear discriminant analysis (LDA) showed that there were three distinct clusters or classes of wines with different aroma profiles. Wines from the Loire region in France and Australian wines from Tasmania and Western Australia were found to have similar aroma patterns. New Zealand wines from the Marlborough region as well as the Australian ones from Victoria were grouped together based on the volatile composition. Wines from South Australia region formed one discrete class. Seven analytes, most of them esters, were found to be the relevant chemical compounds that characterized the classes. The grouping information obtained by GC-MS, was used to train metal oxide based electronic (MOS-Enose) and mass spectrometry based electronic (MS-Enose) noses. The combined use of solid phase microextraction (SPME) and ethanol removal prior to MOS-Enose analysis, allowed an average error of prediction of the regional origins of Sauvignon Blanc wines of 6.5% compared to 24% when static headspace (SHS) was employed. For MS-Enose, the misclassification rate was higher probably due to the requirement to delimit the m/z range considered.