Wine Aging Research Articles

Characterization of volatile organic compounds as potential aging markers in Chinese rice wine using multivariable statistics

There is a close relationship between certain 'aging markers' in wine and the wine's age. This study aimed to characterize all extracted aging markers in Chinese rice wine and distinguish the ages of Chinese rice wine using principal component analysis (PCA) and cluster analysis (CA). A total of 49 potential aging markers (P ≤ 0.05*) were extracted from 71 volatile organic compounds (VOCs) in Chinese rice wine across a range of seven different ages. Of all 49 extracted aging markers, all furans, 2/3 aldehydes and ketones maintained significantly increasing levels with age (P ≤ 0.01**), especially sotolon (0.981**) and acetophenone (0.951**). On the other hand, all sulfides decreased significantly (P ≤ 0.01**). Changes in vanillin, guaiacol, 4-vinylguaiacol (4-VG) and 4-ethylguaiacol (4-EG) also suggested a potential synthesis during the aging process. The results of PCA and CA demonstrated that Chinese rice wines with different ages could be clearly distinguished from each other, which was consistent with the evolution of the 49 aging markers during the aging process. These 49 potential 'aging markers' successfully distinguished ages using PCA and CA. Our results therefore throw light on the characterization of VOCs during Chinese rice wine aging, and provide a quantitative basis for discriminating the ages of Chinese rice wine. © 2019 Society of Chemical Industry.

Effects of high power ultrasound treatments on the phenolic, chromatic and aroma composition of young and aged red wine.

In this study, the effects of both ultrasonic bath and probe treatments on the phenolic, chromatic and aroma composition of young red wine Cabernet Sauvignon were studied and modeled by artificial neural networks (ANNs). Moreover, the effect of high power ultrasound (HPU) along with antioxidants addition (sulfur dioxide and glutathione) was investigated during 6 months of aging in bottles. Lower amplitude and temperature, shorter treatment duration and particularly lower frequency showed a more favorable and milder effect on the chemical composition of wine. In the case of the ultrasonic probe treatment, similar effect was achieved primarily by a larger probe diameter as well as lower amplitude and treatment duration. Selected ANN models showed the best predictions for the chromatic characteristics followed by total phenolics and anthocyanins. The changes induced by HPU treatment after 6 months of aging were mainly detected in the composition of phenolic compounds (both total and individual), where higher concentration of antioxidants (sulfur dioxide and glutathione) slowed down the decrease rate of these compounds during aging. However, HPU treatment did not influence most of the chromatic characteristics and aroma compounds, except lightness and fatty acids. The obtained results indicated that suitable ultrasound treatment might accelerate some aging reactions and shorten the period of wine aging.

Influence of Different Wood Chip Extracts Species on Color Changes and Anthocyanin Content in Synthetic Wine Solutions.

There is restricted knowledge about the potential impact of the use of different wood species on color and anthocyanin changes during the red wine aging process. This lack of knowledge is even greater when no oak wood species are used. Thus, the aim of this study was to carry out a comparative analysis of the impact of wood chip extracts from oak, acacia, and cherry species on the color characteristics and anthocyanins changes using synthetic wine solutions. In this context, several methodologies were used to quantify, color, and anthocyanins changes during the aging time studied. The results indicated that the contact between wood chip extracts and grape skin isolated anthocyanin extracts induced a decrease of color intensity (particularly red color), and the anthocyanin content in the different experimental synthetic wine solutions studied. All chromatic modifications are potentially detected by human eyes because ΔE values were much higher than 3 CIELab units. These tendencies seem to be independent of the wood species used, but are more pronounced for higher contact time between wood chip extracts and anthocyanins. The obtained results may contribute to a better understanding of the chromatic changes of red wines when aged in contact with different wood chip species.

Impact of closure type and storage temperature on chemical and sensory composition of Malbec wines (Mendoza, Argentina) during aging in bottle.

Malbec is the flagship variety of Argentina mainly due to its high oenological value and plasticity to obtain different wine styles. During bottled aging, the chemical and organoleptic composition of wines is subject to changes depending on the aging conditions (closure, oxygen level, temperature, time). However, the combined effect of these factors on chemical composition and organoleptic characteristics of Malbec wines has not been studied yet. Wines were bottled with screw cap and natural cork and were kept in chambers at 15 °C and 25 °C for 2 years. Sampling was performed at 2, 4, 6, 9, 12, 15, 18, 21 and 24 months. Concentrations of free sulfur dioxide, dissolved oxygen, anthocyanins, tannins, esters, volatile phenols, organic acids, and color saturation decreased during the storage process. While, the formation of polymeric pigments, the color attributes (lightness and hue) and the levels of alcohols, norisoprenoids, furanoids and terpenoids increased. At 24 months, Malbec wines were organoleptically different. Wines kept at 15 °C were associated with high sensory perceptions in color intensity and violet tint, those presented a positive correlation with free sulfur dioxide, tannins, and anthocyanins levels. On the contrary, wines aged at 25 °C were linked with high sensory perceptions of dried vegetative and dried fruit aromas. These descriptors were positively correlated with norisoprenoids, furanoids, and terpenoids. In general, the chemical composition and organoleptic attributes of bottled Malbec wines (Mendoza, Argentina) were stable respect closure type employed, but highly sensitive to the combined effect of time and storage temperature. This finding is key to making decisions about the wine style searched, and costs (e.g. refrigeration) involved in the conservation period until consumption.

Investigation of the Antibacterial Activity and Subacute Toxicity of a Quercus crassifolia Polyphenolic Bark Extract for its Potential Use in Functional Foods.

Oak wood is used in barrels for wine aging. During aging, polyphenols are transferred from the barrels to the liquid. Although the bioactivity of oak polyphenols in wines has been extensively studied, no investigation exists on their toxicological properties, which limits their use as functional safe ingredients for other products. In this work, the chemical composition of a polyphenolic extract of Quercus crassifolia bark (QCBe) was studied by GC-MS. Its antibacterial properties on probiotic and pathogenic bacteria and its subacute-oral toxicity were determined as a way to understand the potential impact from its addition to fermented food as a functional ingredient. QCBe shows a selective inhibition of Escherichia coli compared with Lactobacillus bulgaricus and Streptococcus thermophylus. According to the toxicity evaluation, the subacute no-observed-adverse-effect-level was achieved at 11 mg/kg bw/day, whereas the subacute lowest-observed-adverse-effect-level for kidney damage was at 33 mg/kg bw/day. These results suggest that, given the fact an adverse effect was observed after subacute administration of this extract, further longer term toxicological studies are needed to provide sufficient safety evidence for its use in humans. PRACTICAL APPLICATION: Mexico's yogurt market is growing which creates opportunities for the development of some yogurt products as functional foods. As a first step to evaluate its potential use in yogurt formulation, the antibacterial effect of aQuercus crassifolia polyphenolic extract (QCBe)on probiotic bacteria and its subacute-oral toxicity in rats were studied. A low inhibition on probiotic bacteria growth was observed after QCBe addition to Lactobacillus bulgaricus and Streptococcus thermophylus cultures. Exposure to QCBe for a subacute duration resulted in renal injury in rats at dosages greater than or equal to 33 mg/kg/bw/day. This adverse effect indicates the importance of performing further long-term toxicological assessments prior to the addition of QCBe to a food like yogurt, which is regularly eaten by consumers.

Changes in Smoke-Taint Volatile-Phenol Glycosides in Wildfire Smoke-Exposed Cabernet Sauvignon Grapes throughout Winemaking

When grapes are exposed to wildfire smoke, several smoke-related aroma compounds can be transferred to the berries and become glycosylated. Although the compounds do not contribute to grape aroma in the glycosylated form, the free volatile phenols can be released throughout winemaking and wine aging to produce undesirable “smoke tainted” wines. Measurement of the intact glycosides provides insight on the potential flavor of a wine and provides information on the effect of winemaking practices on release of volatile aroma compounds from glycosidic precursors. Smoke taint-associated volatile-phenol glycosides in Vitis vinifera cv. Cabernet Sauvignon grape berries were tentatively identified and semi-quantitated using a comprehensive database coupled with ultra-high performance liquid chromatography and accurate-mass time-of-flight tandem mass spectrometry. Eight trisaccharide volatile-phenol glycosides were tentatively identified for the first time in grapes. The method developed here was applied to monitor changes associated with smoke exposure in 31 volatile-phenol glycosides during winemaking. The most hydrolytic time period during the winemaking process was the first half of fermentation with Saccharomyces yeast (EC-1118), after which there was little effect on the phenolic glycosidic profile of fermenting wines. This is the first report to monitor changes of these 31 phenolic glycosides during winemaking using direct measurement of the glycosides. The information can be used to improve knowledge of the changes in smoke-taint glycosides and release of phenolic compounds that affect sensory properties of smoke-affected grapes and wines.

Effect of Vine Water and Nitrogen Status, as Well as Temperature, on Some Aroma Compounds of Aged Red Bordeaux Wines.

Wine aging bouquet is defined as a positive, complex evolution of aromas during bottle aging. The aim of this study was to look for the link between some of the vine status parameters and the development, during wine aging, of volatile compounds such as DMS, tabanones, and some wine aromatic heterocycles. The potential influence of air temperature was investigated as well as vine nitrogen and water status. Wines were obtained by microvinification from plots of Vitis vinifera L. cv. Merlot, Cabernet-Sauvignon, and Cabernet franc, over vintages from 1996 to 2007, and cellar-aged until 2014. Wine aging aromas were quantified using gas chromotography-mass spectrometry. The effects of the vintage and vine water and nitrogen status were greater than the varietal effects. The nine aroma compounds measured showed very high levels in the 2003 vintage. The results revealed a positive link between vine nitrogen status and dimethyl-sulfide and N, S, O-heterocycle levels measured in the aged wines. Levels of 4-[2-butylidene]-3,5,5-trimethyl-2-cyclohexen-1-one and 4-[( 3E)-1-butylidene]-3,5,5-trimethyl-2-cyclohexen-1-one (megastigmatrienones; tabanone) isomers increased when the vines were affected by a water deficit.

Catechol versus carboxyl linkage impact on DSSC performance of synthetic pyranoflavylium salts

Anthocyanins are the main polyphenolic dyes found in young red wines, which are transformed into more stable structures such as pyranoanthocyanins, during wine ageing and maturation. While anthocyanins practically lose their red color between pH 1 and 5, as a result of the formation of colorless hemiketals, pyranoanthocyanins practically do not change their color intensity. For that they constitute a photosensitizer family with great potential for bio-inspired dye-sensitized solar cells (DSSCs). In this work, a series of pyranoanthocyanin derivatives were designed, synthesized and applied for the first time as dye sensitizers in DSSCs. A relation was established between dye structure and cell efficiency. Specifically, the influence of different linker units, carboxyl and catechol, was studied in terms of their influence in the various parameters related to DSSC efficiency. The presence of the catechol unit was shown to be essential for efficient electron injection of the dye into the TiO2 semiconductor, since carboxylic units showed a deleterious effect in electron injection due to their electron withdrawing character. An overall efficiency of 1.15% was obtained for the best performing compound, 10-catecholpyrano-3′,4’,5,7-tetrahydroxyflavylium, with no further optimization.

Stability studies: Room for improvement

Anthocyanins are the main polyphenolic dyes found in young red wines, which are transformed into more stable structures such as pyranoanthocyanins, during wine ageing and maturation. While anthocyanins practically lose their red color between pH 1 and 5, as a result of the formation of colorless hemiketals, pyranoanthocyanins practically do not change their color intensity. For that they constitute a photosensitizer family with great potential for bio-inspired dye-sensitized solar cells (DSSCs). In this work, a series of pyranoanthocyanin derivatives were designed, synthesized and applied for the first time as dye sensitizers in DSSCs. A relation was established between dye structure and cell efficiency. Specifically, the influence of different linker units, carboxyl and catechol, was studied in terms of their influence in the various parameters related to DSSC efficiency. The presence of the catechol unit was shown to be essential for efficient electron injection of the dye into the TiO2 semiconductor, since carboxylic units showed a deleterious effect in electron injection due to their electron withdrawing character. An overall efficiency of 1.15% was obtained for the best performing compound, 10-catecholpyrano-3′,4’,5,7-tetrahydroxyflavylium, with no further optimization.

Phenolic profile and colour acquired by the wine spirit in the beginning of ageing: Alternative technology using micro-oxygenation vs traditional technology

Alternative technologies have been extensively investigated towards a more sustainable ageing of red wine, but few studies were made on wine spirits. Moreover, the effect of micro-oxygenation on wine spirits’ ageing is still unknown. This work examined the effect of micro-oxygenation and wood staves applied in 1000 L stainless steel tanks versus 250 L wooden barrels on the phenolic composition and chromatic characteristics acquired by the wine spirit over the first six months of ageing. Two different kinds of wood, Limousin oak and chestnut, were used. Significantly higher total phenolic content and individual contents of low molecular weight phenolic compounds (syringic acid, ellagic acid, vanillin, syringaldehyde, coniferaldehyde, sinapaldehyde and umbelliferone) were obtained with micro-oxygenation and staves than with barrels, for both kinds of wood. Accordingly, greater colour evolution (lower lightness, higher saturation and higher intensities of red, yellow and brown hues) was achieved in the former. These results were ascribed to a faster extraction and its balance with several phenomena involving the wood-derived compounds in the specific environment created by the direct supply of oxygen. A synergistic effect between the alternative technology and the chestnut wood was also observed.

Engineering Lactococcus lactis for the production of unusual anthocyanins using tea as substrate

Plant material rich in anthocyanins has been historically used in traditional medicines, but only recently have the specific pharmacological properties of these compounds been the target of extensive studies. In addition to their potential to modulate the development of various diseases, coloured anthocyanins are valuable natural alternatives commonly used to replace synthetic colourants in food industry. Exploitation of microbial hosts as cell factories is an attractive alternative to extraction of anthocyanins and other flavonoids from plant sources or chemical synthesis. In this study, we present the lactic acid bacterium Lactococcus lactis as an ideal host for the production of high-value plant-derived bioactive anthocyanins using green tea as substrate. Besides the anticipated red-purple compounds cyanidin and delphinidin, orange and yellow pyranoanthocyanidins with unexpected methylation patterns were produced from green tea by engineered L. lactis strains. The pyranoanthocyanins are currently attracting significant interest as one of the most important classes of anthocyanin derivatives and are mainly formed during the aging of wine, contributing to both colour and sensory experience.

Wine Aging Technologies

Wine aging is a desirable and valuable process, commonly used to improve wine quality, and traditionally carried out in oak wooden casks [...]

Prediction Models to Control Aging Time in Red Wine.

A combination of physical-chemical analysis has been used to monitor the aging of red wines from D.O. Toro (Spain). The changes in the chemical composition of wines that occur over the aging time can be used to distinguish between wine samples collected after one, four, seven and ten months of aging. Different computational models were used to develop a good authenticity tool to certify wines. In this research, different models have been developed: Artificial Neural Network models (ANNs), Support Vector Machine (SVM) and Random Forest (RF) models. The results obtained for the ANN model developed with sigmoidal function in the output neuron and the RF model permit us to determine the aging time, with an average absolute percentage deviation below 1%, so it can be concluded that these two models have demonstrated their capacity to predict the age of wine.

Exploiting combined absorption and front face fluorescence spectroscopy to chase classification: A proof of concept in the case of Sardinian red wines.

We present the analysis of optical spectroscopy fingerprints of three different varieties of Sardinian red wine, Carignano, Cannonau and Monica, belonging to Italian DOC (Controlled Origin Designation) red wines family. We selected 15 commercial wines (five for each variety), produced in the middle and south regions of Sardinia form monovarietal grapes. Despite different grapes, farming and tasting, all the samples share common absorption and fluorescence features. A two steps analysis is applied to achieve good classification of the wines. We recorded typical absorbance spectra with a large absorption below 300 nm and a visible absorption band at about 520 nm. Colour attributes according to chromaticity coordinates were evaluated by means of transmittance data and coupled to wine aging data to achieve classification. Despite similar values of lightness (L*), chroma (C*ab), and hue angle (h°ab) for the three varieties, good clustering was gathered for Carignano and Cannonau wines, whilst Monica variety has wide spread chromatic coordinates. UV excited fluorescence spectra display large and composite emission bands from the near UV down to the whole visible range. We performed multivariate analysis in the framework of the principal component analysis of fluorescence spectra coupled with absorption ones being able to achieve good clustering between the three varieties. One anomaly among Cannonau wines is discussed.

Aging of Aglianico and Sangiovese wine on mannoproteins: Effect on astringency and colour

During the last years different commercial preparations based on yeast derivatives have been used in order to replace traditional ageing on lees. Three commercial mannoproteins (MP; MF; MS) were tested in Aglianico and Sangiovese red wine during one year of aging to evaluate the influence on astringency characteristics (astringency intensity and 16 subqualities), colour parameters (CIE L*a*b* coordinates, total anthocyanins, pigmented polymers) and reactive phenolic compounds (BSA-reactive tannins, saliva-reactive tannins, vanillin reactive flavans) after 3, 6 and 12 months. The taste, odor and aroma profiles completed the sensory evaluation of one-year aged wines. The effect of commercial mannoproteins on studied parameters depended on wine variety and aging period. As regard wine colour evolution, the formation of pigmented polymers was promoted from the 6th month in Aglianico by MS and MF, and in Sangiovese by all mannoproteins. Regarding wine sensory evaluation, MP reduced the astringency of Aglianico and enhanced the positive subqualities, while all mannoproteins favored spicy and balsamic notes revelation. In Sangiovese, green tannins and herbaceous notes decreased at the same time as floral notes, satin tannins and wine body augmented. Finally, the use of commercial mannoproteins improved some sensory characteristics of red wines related to positive astringency subqualities and aroma persistence.

Precision enology in Tawny Port wine aging process: Monitoring barrel to barrel variation in oxygen, temperature and redox potential

Tawny Port wine is a category of the famous Portuguese fortified wine commercialized worldwide and produced in the Douro Demarcated Region. Tawny Port wine oxidative aging is a multifactorial process critical for reaching the wanted quality. Real time monitoring of important intrinsic and extrinsic factors that are known to affect both time and quality of the aging process are important to optimize and to manage the natural variability between wines aged in different long-used wood barrels. This study presents the design, development and implementation of a remote distributed system to monitor parameters that are known to be critical for Tawny Port wine aging process. Results indicate that the distributed monitoring system was capable to detect differences between oak wood barrels and between the different storage conditions. Indeed, oxygen and redox potential were the wine's parameters where the differences found between different barrels were greater under the same storage conditions. Considering that Tawny Port wine aging process is oxidative, a variation in the wine's aging process between different wood barrels is to be expected. Actually, significant differences were detected in the oxygen consumption rate amongst the different barrels. Differences in the phenolic composition was also observed in the aged wine (controlled temperature and room temperature).

Genetic, morphological and chemical characterisation of the grape variety 'Probus' (Vitis vinifera L.)

In the middle of the 20th century, varieties of Vitis vinifera locally grown in the Balkans were crossed with varieties from Western Europe with the aim of improving wine quality. The variety 'Probus' originated from the crossing of 'Kadarka' and 'Cabernet Sauvignon' and was released in 1983. The acreage of 'Probus' has recently increased in Serbia, along with the reputation of its wine. A detailed characterisation of this variety is therefore desirable. Traits with high heritability such as phenology, leaf morphology, anthocyanin profile, and microsatellite DNA were compared between 'Probus' and its parents were compared. 'Probus' and 'Cabernet Sauvignon' showed a synchronized phenology and highly similar leaf shape. The anthocyanin composition of 'Probus' wines was more similar to 'Cabernet Sauvignon' than to 'Kadarka', due to high anthocyanin content and high relative abundance of tri-substituted monoglucosides and acetylated conjugates, which are usually associated with deeper and more durable colour during the ageing of red wines. For total anthocyanin content, 'Probus' performed even better than 'Cabernet Sauvignon' in the environmental conditions of Northern Serbia. 'Probus' has compact bunches and large berries typical of the high-yielding 'Kadarka'. DNA analysis confirmed the alleged parentage of 'Probus' and revealed the high heterozygosity of its genome, as result of the cross between distantly related parents. These results confirm that 'Probus' is a promising variety for the production of quality red wines in Southeastern Europe.

Effect of high hydrostatic pressure on selected red wine quality parameters

The aim of this work was to examine the possible use of High Hydrostatic Pressure (HHP) as an alternative method for wine preservation, which could also lead to the production of wines with reduced amounts of SO2. For this purpose, red wine samples containing 0 ppm, 30 ppm, 60 ppm and 100 ppm of sulphur dioxide (SO2) were subjected to pressure of 350 MPa for 10 min at 8 ∘C. A second set of samples containing only SO2 was used as control. Colour parameters, acetic acid, total anthocyanin and phenolic contents and antioxidant activity were determined over a period of twelve months. During the first four months, most of the differences observed regarding the chemical composition of the pressurized and unpressurized wines were not statistically significant. However, after the period of six months, the pressurized samples in general were characterized by higher average values % yellow colour and acetic acid and lower of % red colour, total anthocyanin and phenolic content compared to the non-pressurized ones. The results obtained could be a possible indication that HHP could accelerate the polymerization reactions reducing the time needed for wine ageing. HHP combined with reduced SO2 contents might be a promising technology for wine industry.

Image of O2 dynamics released by oak wood submerged in model wine with nanoparticle sensors

Oxidation of wine while in contact with oak wood is a well-known fact and recognized as an important process in wine ageing. The slow and continuous diffusion of oxygen from the oak wood entrapped in its porosity occurs and encourages the reactions usually related with wine aging. In this work, oxygen sensitive particles were used to study the oxygen dynamics from different anatomical regions of the oak wood and simultaneously the oxygen increasement because of the deoxygenation of the wood and the oxygen depletion due to its consumption by the tannins and other compounds released from the wood. To this end, core-shell-type PSPVP nanoparticles stained with Macrolex Fluorescence Yellow and Pt-TFPP were employed as reference and oxygen-sensitive particles respectively. Moreover, a Guppy Pro RGB camera was employed to monitor the particles performing ratiometric oxygen imaging, using the green and red channels to acquire the light emitted from the reference and the oxygen-sensitive particles respectively. Because the volume of nanosensors corresponding to each surface unit is very different from that of the wood region, different exposure times were chosen to obtain the images at each of the times. The results show the wood degassing process during the first minutes of the experiment, the oxygen release from different structural elements of the wood, its consumption by the released compounds from wood and the diffusion of the oxygen through the model wine.

Influence of summer management practices and date of harvesting on organic acids concentration and sugar concentration in grapes of Vitis vinifera L., cv. Riesling

The impact of summer canopy management was investigated in Vitis vinifera L., cv. Riesling. Sugar and organic acid concentrations were measured for the six defoliation treatments. Titratable acidity (TA) was measured twice before harvest and once at the date of harvest. The same measurements were done twice during wine ageing. The young wine was measured for concentrations of malic, tartaric and volatile acids. Treatments with appropriate defoliation, where shortened lateral shoots (up to two leaves) were retained, supported the process of wine grape ripening to the greatest extend in the cool climate of the Czech Republic, while treatments with almost no defoliation yielded the worst results. The TA decreased during fruit ripening after veraison and continued to decrease during wine maturation. The tendency of decreasing with time was shown for the malic to tartaric acid ratio as well. Concentrations of volatile acids were sufficiently low in each of the treatments.