Tag Archives: terroir

Using Rare Earth Elements to Determine the Authenticity and Geographic Origins of Moscato d’Asti Wines

Posted on April 17, 2013 by Becca| 2 Comments

 

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Wine, unlike many other food and beverage products, is somewhat frequently more subject to fraudulent practices that result in significant financial losses for those unknowing victims purchasing what they thought was a high quality wine when in fact it is a fake. It is therefore important to develop ways to test the authenticity of the wine in order to be sure what you’re investing in is real. Similar to the authenticity of a wine is the traceability of wine: is the wine from the geographical location that is indicated on the bottle?

Previous studies have found that lanthanides, the “rare earth elements” on the periodic table between atomic numbers 57 and 71, may be good geochemical markers for determining authenticity and traceability of foods, and have been shown to determine origins of several foodstuffs, including hazelnuts. Many

By LeVanHan (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

By LeVanHan (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

studies have shown that there is good traceability using lanthanides up until the must stage, as the lanthanide profile remains fairly constant throughout the growing season and through harvest. However, since wine undergoes many chemical changes during the winemaking process, using lanthanides may actually be problematic for determining authenticity and traceability, as it’s been shown that using bentonite during the clarification process changes the lanthanide profile in wine, thereby making authenticity determinations a lot more difficult. To date, it has not been made clear how the winemaking process alters the lanthanide fraction of wine, and if this alteration results in problems with testing authenticity or traceability of those wines or not.

The study presented today aimed to add to the literature on using lanthanide signatures to determine authenticity and traceability using Moscato d’Asti wine, and to determine if the winemaking process results in the alteration of this lanthanide profile and whether or not this method is appropriate for catching fraudulent wines or determining authenticity and traceability in general for wine.

Methods

For determining the traceability from soil to must; soils, grapes, and musts were collected from the experimental vineyard of Centro Sperimentale Vitivinicolo Tenuta La Cannona in Carpeneto, AL, Italy. For determining authenticity of Moscato d’Asti musts and wines, samples were collected from various producers throughout the Piedmont region of Italy. All must samples were frozen prior to testing, and thawed 4 hours prior to analysis.

Elemental analysis was performed on soil, grape, and must samples, focusing primarily on the rare earth elements/lanthanides. These analyses were performed on a X5 Series inductively coupled plasma mass spectrometer.

Results

• The rare earth element profile including lanthanides was nearly identical from soil to grape to must for Moscato d’Asti.
• Cerium (140Ce) was found to be most abundant in all samples tested.
• Filtering the musts with amorphous silica diatomites (rectification step in winemaking) resulted in a marked change in the rare earth element profiles, as the profile in filtered samples were found to be drastically different than the profile of the original must samples.
o The most significant changes were noted for the elements 175Lu and 172Yb (Lutetium and Ytterbium, respectively).
• The clarification of the musts using Bentonite provided an even more drastic change in the rare earth element profile compared with the must sample after the filtering step and the original must.
o This may be attributed to the fact that Bentonite releases metal ions into the must during the clarification process, thus significantly altering the rare earth element profile of that must.
o Therefore, it is not possible to use the rare earth element profile of wine to determine the traceability of the wine, since this profile is so drastically altered during the bentonite treatment in the clarification step of winemaking. If an alternative to bentonite that did not release metal ions into the must was used, then perhaps this method of analyzing the rare earth element profile to measure traceability would be useful.
o Traceability is completely possible and very accurate from the soils to the musts, but not after the winemaking process using bentonite.
• Principal components analysis (PCA) showed a clear separation in rare earth elements of Italian wines between geographical locations, though some of the separations were narrow.
o This result indicates that it is possible to determine if a particular wine is from a particular geographic location or not.

Conclusions

I found it fascinating that one can trace a must back to the location where the grapes grew in the soil, simply by measuring the profile of rare earth elements in the must, grapes, and soil. Those rare earth elements that are in the soil of a particular area are taken up by the grapevine and transported via the xylem and phoelm into the grape berries without altering the profile from soil to grape. It makes me wonder if this is evidence of terroir—the rare earth element profile appears to be different for every geographical location, as evident in the PCA analysis during the authenticity portion of this study, so perhaps this is the sort of scientific evidence needed to “prove” the existence of terroir. That’s just a thought, but I think it’s a good starting point.

After the musts are chemically altered by the winemaking process, particularly after the clarification by bentonite stage, the rare earth element profile no longer represents the profile of the original must nor does it represent the profile of the grapes and soil from which the wine came. This makes sense to me,

By Nikilux (Own work) [CC-BY-SA-3.0-lu (http://creativecommons.org/licenses/by-sa/3.0/lu/deed.en)], via Wikimedia Commons

By Nikilux (Own work) [CC-BY-SA-3.0-lu (http://creativecommons.org/licenses/by-sa/3.0/lu/deed.en)], via Wikimedia Commons

as if you’re going to add any chemical you’re likely going to alter the chemical make-up of that wine due to chemical reactions that may take place. The authors suggested that wine that is not treated with bentonite may show similar rare earth element profiles to the original profiles, though I am not convinced. There are other chemicals added to wine during the winemaking process, and I’m not yet convinced that those chemicals might not interact and alter the rare earth element profile of the finished wine. I’d like to see a follow up study examining this issue.

Overall, I thought this was a really neat study, despite the fact that it was relatively short and was lacking some treatments that I would have liked to see (i.e. different stages during the winemaking process). I would love to see a follow up to this study perhaps taking it in the direction of scientifically showing the existence of terroir, and also perhaps a follow up looking at grapes in other parts of the world.

I’d love to hear what you all think of this topic! Please feel free to leave your comments!

Source: Aceto, M., Robotti, E., Oddone, M., Baldizzone, M., Bonifacino, G., Bezzo, G., Di Stefano, R., Gosetti, F., Mazzucco, E., Manfredi, M., Marengo, E. 2013. A traceability study on the Moscato wine chain. Food Chemistry 138: 1914-1922.

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Thank Bird Droppings for Terroir?: The Role of Migratory Birds in the Spread of Wine Yeasts

Posted on December 5, 2012 by Becca| 4 Comments

 

Saccharomyces cerevisiae is one of the most important yeasts in winemaking, the distribution of which is widespread and as a result the origin of which is unknown.  What is known is that S. cerevisiae is not an airborne species and therefore requires something else to move it from place to place.  Recent research has found that insects, including bees and wasps, are one such vector for S. cerevisiae, but it does not explain all movement of this yeast in nature.

In addition to insects, migratory birds have also been studied for their abilities to transfer microorganisms that can infiltrate the human population.  To date, most studies have focused on bacterial transfer by migratory birds, with very little focused on yeasts.

Migratory birds are well known for travelling great distances.  They embark on a round-trip journey in the spring and again in the fall; starting at their nesting location, travelling great distances to follow the flow of food resources, and

By H. K. Job [Public domain], via Wikimedia Commons

eventually returning back to their nesting location.  At times, the birds will need to stop at resting areas if they have deleted their fat stores to a point where they require more before being able to fly further distances.

The purpose of today’s study was to examine the potential of migratory birds in transporting yeasts at great distances (as opposed to the shorter distances – 10km – traveled by insect vectors); to identify the kinds of yeasts present; and to determine how long after ingestion by the birds are the yeasts dispersed into the environment (i.e. when did the birds, ahem…eliminate them….).

Methods

Experimental sites were located at known migratory bird stopover points within Sicily during the spring and autumn seasons.  This location chosen would capture yeast transporting information from migratory birds travelling from Africa to Europe.

At the stopover point, birds were captured near woody areas just as they were landing.  A total of 349 birds were captured.  After they were captured, birds were ringed/tagged, identified by species, and measured for subcutaneous fat amount (SFA).  Note: when SFA values are between 0 and 1, the fat stores are too low to continue and the bird must stop to refuel.

Yeasts were isolated from the birds’ cloacae (a fancy term for the place waste, urine, and reproductive fluids are eliminated from…).  Yeasts were identified using genetic analysis.

By Korall (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons

 Results

  • Yeasts were found in 32.66% of the birds captured.
  • The following bird families were found to have the most yeasts present in their cloacae:
    • Muscicapidae
    • Passeridease
    • Turdidae
    • Fringillidae.
  • Genetic analysis identified 125 types of yeasts.  Yeasts identified in bird cloacae included the following:
    • Aureobasidium pullulans; Candida albicans; Candida glabrata; Candida inconspicua; Candida spp.; Candida stellimalicola; Cryptococcus aureus; Cryptococcus carnescens; Cryptococcus magnus; Debaryomyces hansenii; Hanseniaspora guillrmondii; Metschnikowia pulcherrima; Pichia kudriavzevii; Pichia terricola; Pseudozyma aphidis; Rhodotorula mucilaginosa; Saccharomyces cerevisiae; Sporisorium penniseti
  • The yeastspecies most frequently found in migratory bird cloacae were:
    • H. guillrmondii – 17.6%
    • C. albicans – 16%
    • S. cerevisiae – 14.4%
    • A. pullulans – 12%
  • 72 of the 125 yeast isolates found were associated with known wine-related yeasts.  These yeasts include the following:
    • A. pullulans; D. hansenii; H. guillrmondii; P. kudriavzevii; P. terricola; M. pulcherrima; R. mucilaginosa; and S. cerevisiae.
  • The following bird species were found to have the most yeast biodiversity in their cloacae:
    • Garden warbler and subalpine warbler
  • S. cerevisiae was found most often in the following bird species:
    • Garden warbler, icterine warbler, redstar, whitethroat, subalpine warbler, winchat, and spotted flycatcher.
  • For birds with SFA values between 0 and 1 (i.e. time for the birds to stop and refuel), 58.4% of the total yeasts and 63.89% of the wine-related yeasts were isolated.
    • The most common wine-related yeasts collected from birds with SFA values between 0 and 1 were A. pullulans at 66.66%, and S. cerevisiae at 66.67%.
  • 18 isolates of S. cerevisiae were found.
    • Of these, 6 strains were identified.
    • 9 of the isolates found were located on Lampedusa island.  From these, 3 strains were identified.
    • 8 of the isolates found were located on Ustica island.  From these, 2 strains were identified.
      • The strains found on Lampedusa island were different from the strains found on Ustica island.
      • As a result of this, the authors hypothesize that the birds landing on Lampedusa are coming from a different starting point than the birds landing on Ustica.
  • The average amount of time for the dispersion of yeast by birds was about 12 hours after initial ingestion.
    • This time allows a distance of about 300-350km to be travelled by the birds.

Conclusions

The results of this study show that migratory birds are important players in the distribution and biodiversity of yeasts (both wine yeasts and non-wine yeasts) in the environment in the region of Sicily and that the yeasts were able to survive the entire trip from start to rest stop in the bird’s gastric system.  To determine if similar results are found in other regions of the world, the study should be repeated in other migratory bird habitat areas throughout the globe.

The authors also found that the yeast strains in a particular location were more similar to one another than the yeast strains found in a location further away.  They suggest this may support the idea that migratory birds contribute to the terroir of an area, since the yeasts they spread in the area are genetically

Photo by barockschloss: http://farm8.staticflickr.com/7265/7560941750_e279f0cf00.jpg

different from yeasts spread by other birds in a different area, which would then produce slightly different wine in both locations.  If the same birds are travelling back and forth to the same locations, theoretically they are dispersing the same yeasts to a particular area over and over again, thus contributing to the uniqueness / terroir of the area.

The authors did not mention this, but I think these results also highlight some of the reasons why conserving migratory bird habitat is very important.  Of course, there are many other important reasons why migratory bird habitats should be conserved, most important of which is to ensure their survival, but also to maintain biodiversity of the entire ecosystem they inhabit.

Conserving migratory bird habitat would also effectively allow the maintenance of part of the system that defines terroir, which is further evidence of the complicated nature of ecosystems.  It shows that harming this one part of the system (i.e. migratory bird habitats) would have profound consequences for not only biodiversity and migratory bird health survival, but also potentially for the uniqueness that defines each individual wine region throughout the world.

I’d love to hear what you all think!  Please feel free to your comments and discussions.

Source: Francesca, N., Canale, D.E., Settanni, L., and Moschetti, G. 2012. Dissemination of wine-related yeasts by migratory birds. Environmental Microbiology Reports 4(1): 105-112.

Posted in Environmental Science

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Distinguishing Terroir Effects Using NMR and ECVA Analysis

Posted on July 12, 2012 by Becca| 6 Comments

An aside before this post begins….

This is the 100th article reviewed by The Academic Wino!!!  We’ve posted over 130 total posts on this blog, but this one is the 100th peer reviewed article presented!  I can’t believe I’ve read 100 papers so far!  Here’s to the next 100!

http://decanter.media.ipcdigital.co.uk/
11150%7C00000330d%7C3179_wine-fraud.jpg

Throughout the food and beverage industry, particularly in the high-end wine business, fraud is an ever present and serious threat to the authenticity of the product and the industry.  Wine, in particular, is relatively easy to defile, since it is very chemically complex and changes may go unnoticed if not examined thoroughly.  Wine consists of hundreds of compounds that vary depending upon many factors, including but not limited to grape variety, environmental conditions, and winemaking techniques.  All of these combined result in a wine that is unique, and that can be analyzed through several methods to determine its authenticity, including infrared spectroscopy, X-ray absorption, and dielectric fingerprinting.

The primary compounds in wine are formed primary as a result of the alcohol and malolactic fermentations of grape must.  In addition to having good quality grapes, control of the fermentation processes (as well as other steps in the winemaking process) are critical in producing a high quality wine.  To monitor quality of wine during these processes, several methods may be employed, though the use of Nuclear Magnetic Resonance, or NMR. has more recently been investigated as a possible method for doing so. 

Previous studies have shown that by using NMR analysis, they were able to discriminate between grape samples from different environments from different locations in southwest France.  This suggests that NMR analysis may be a successful method for analyzing authenticity and/or quality of wine all the way down to the level of “terroir”; a term which encompasses the specific environmental characteristics of a particular site that all contribute to create a unique finished wine.

The goal of the article presented today was to analyze the winemaking process from wines made in Rioja, Spain by NMR metabolomic fingerprinting and advanced chemometrics to evaluate the chemical differences between specific events during the winemaking process, the vintage, the geographical origin, as well as specific wineries.

Methods

9 winemaking cooperatives were selected for this study, including three from Rioja Baja, five from Rioja Alta, and one from Rioja Alavesa.  Specifically, the cooperatives selected were from Arnedo, Alcanadre, Arenzana de Abajo, Navarette, Haro, San Asensio, Uruñuela, and Labastida.  Vintages studied were from 2006, 2007, and 2008.  Five samples from each cooperative at different time points during the fermentation process were collected.  Time points were 1) before alcoholic fermentation; 2) at the end of alcoholic fermentation; 3) the beginning of malolactic  fermentation; 4) middle of malolactic fermentation; and 5) after malolactic fermentation. 

In total 111 samples were obtained from three vintages, nine winemaking cooperatives, and five fermentation time points.

Nuclear Magnetic Resonance was performed on all wine samples.

Principle Components Analysis (PCA) was performed on the three main wine NMR spectra analyses, separating the samples into three different regions (aromatic region, carbohydrate region, and organic acid region).  Using PCA analysis on the NMR spectra accounts for different types of functional groups (similar molecular compound structures) that help improve chemometric performance (i.e. the ability to extract information from chemical analysis data).

Extended Conical Variable Analysis (ECVA), which functions to determine which region on the NMR spectra is responsible for separation among different groups, was also performed.

Results

  •  The transition from grape must to wine was evident on the NMR spectra as the disappearance of carbohydrate signals in the must and appearance of alcohol and organic acid signals in the wine.

o   The aromatic content during this stage remained constant.

  • In wine, carbohydrates did not completely disappear, but left a complex fingerprint.
Figure 2 from  Lopez-Rituerto et al, 2012.


  • During alcoholic fermentation, the major variation in the NMR spectra between samples was in the ethanol content.
  • During malolactic fermentation, the major variation in the NMR spectra between samples was in malic acid and lactic acid (not surprisingly).
  • When differentiating between subareas inside Rioja, the NMR spectra showed two distinct separations between Rioja Alta plus Rioja Alavesa and Rioja Baja.

o   Rioja Alavesa could not be distinguished between Rioja Alta, possibly due to its very close proximity to the area.

o   The best region in the spectra to distinguish these subareas was the aromatic region, though the PCA analysis was only able to explain 40.2% of the variation.

  • The three vintages studied were distinguished on the NMR spectra using the aromatic region, though not clearly.
  • Using ECVA allowed the researchers to reduce the error rate and misclassifications to 0 or near 0 in all cases.
  • Using ECVA in conjunction with NMR, all three vintages were clearly distinguished.
  • Using ECVA in conjunction with NMR successfully distinguished not only between subareas of Rioja, but also between individual wineries.

o   The two compound signals that showed the clear distinction between individual wineries in Rioja were isobutanol and isopentanol.

Conclusions

The results of this study suggest that isobutanol and isopentanol may be important biomarkers for differentiating wine from individual wineries in a wine region.  Also, different stages of the winemaking process may be effectively analyzed and distinguished using NMR analysis.

Results show that wines can be differentiated using NMR analysis to different time points during the fermentation process, as well as in different subareas of a wine region, and also different vintages.  Combining NMR analysis with ECVA analysis, wines can be distinguished as specifically as the individual winery level.  These results may be very important in distinguishing between wines if needed for authenticity confirmation or fraud investigations. 

This study only investigated one wine region, thereby further studies would be needed in other wine regions to determine if this type of analysis is applicable on a global scale, or if the results are just a regional phenomenon.

I’d love to hear what you all think about this topic!  Please feel free to leave your comments below!

Source: Lopez-Rituerto, E., Savorani, F., Avenoza, A., Busto, J.H., Peregrina J.M., and Engelsen, S.B. 2012. Investigations of Rioja Terroir for Wine Production Using 1H NMR Metabolomics. Journal of Agricultural and Food Chemistry 60: 3452-3461.

DOI: dx.doi.org/10.1021/jf204361d



I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!

Posted in Chemistry

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The Phenolic Composition of Cabernet Sauvignon Wines in China: Demonstrating Terroir Effects

Posted on July 4, 2012 by Becca| 2 Comments

Phenolic compounds, which are found in grapes, can significantly influence the aroma, flavor, mouthfeel, color, and overall quality of a wine.  These compounds are found naturally in grapes, however can also be synthesized throughout the fermentation and aging processes.  As a result of this, there are many factors that can influence the phenolic composition of a wine, including but not limited to; grape variety, environmental influences, and winemaking techniques.  For wines that are single variety based and not aged after fermentation, the phenolic composition of the wine is highly dependent upon the grape and the conditions in the vineyard. 

Specifically, this is what the term “terroir” embodies: it is the definition of the geographical and environmental origin of the grapes that include characteristics such as soil type, climate, and topography, and who all those things combine to affect the composition and quality of a wine.  Favorable terroir conditions can produce very high quality grapes, which is a critical starting point for a good wine.  By understanding how terroir affects the phenolic composition of grapes, vineyards managers or winegrowers will have a greater understanding of how to manage and maintain the grapevine that will produce high quality wines.

http://3.bp.blogspot.com/_ba7lj8a1Awo/
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3d8gtOqRyJU/s1600/china_map.jpg

There is a lot known about terroir effects on grapes and wine throughout many portions of the world, however, there is little known that specifically compares individual phenolic compounds of single varietal wines from different winemaking regions, and even less so known about these effects in the newer wine regions of China.

The wine regions of China are very ecologically diverse, considering they are spread all over the vast country.  The Yunnan Zone can be found at altitudes between 1900 and 2400m above sea level; the Gansu Qilian Zone is located next to a desert; the Ningxia Helan Zone is past the mountains; the Yantai Shandong Zone and Changli Hebei Zone are by the sea; and finally the Huailai Hebei Zone is located in a cooler climate.  It is because of these regional differences that there is great potential for regional terroir effects in wines produced from Chinese grapes. 

The goal of the study presented today was to analyze the differences in phenolic composition in Cabernet Sauvignon vines from different winegrowing regions in China.

Methods

 5 growing regions in China were studied: Deqin of Yunnan (YNDQ); Yuquanying of Ningxia (NXYQY); Yuma of Ningxia (NXYM); Qilian of Gansu (GSQL); Changli of Hebei (HBCL); and Yantai of Shandong (SDYT). 

Cabernet Sauvignon vines were studied, since they are easily found growing in all wine regions of China.  Grapes were harvested at their full-ripened state and were in strict accordance with local wine production technical rules.  Wines went through alcohol and malolactic fermentations, but did not age afterward. 

In each growing region, two to four wineries were chosen and about 1000mLof fresh wine from each winery was collected from at least two different fermentation processes.  To ensure only regional terroir characteristics were at play, all wines from each growing region were pooled.  Each wine sample was studied in triplicate.

Anthocyanin phenolics were analyzed, as well as non-anthocyanins including flavan-3-ols, flavonols, hydroxybenzoic acids, hydroxycinnamic acids, and stilbenes.  Anthocyanins were quantified by using malvidin-3-O-glucoside as a standard, and flavanols, flavonols, hydroxybenzoic acids, hydroxycinnamic acids and stilebenes were quantified by using catechin, quercetin, gallic acid, caffeic acid, and resveratrol, respectively.

Results

Anthocyanins

  • 24 anthocyanins were identified in Chinese Cabernet Sauvignon wines.

o   All 24 were found in each Chinese growing region studied.

  •  Wine from the YNDQ region had the highest levels of anthocyanins.
  • Wines from GSQL and NXYQY regions had significantly lower levels of anthocyanins (due to very low delphinidin derivatives).
  • Cyanidin-3-O-glucoside and peonidin-3-O-glucoside were 5 times higher in YNDQ wines than wines from any other region.
  • Wines from HBCL had the highest levels of malvidin-3-O-glucoside and malvindin-3-O-(6-O-acetyl)-glucoside.
  • There were significant differences in anthocyanin levels between wine regions in China.

Flavan-3-ols

  • 16 flavan-3-ols were found in wines from all Chinese growing regions studied.
  • SDYT region displayed the highest levels of flavan-3-ols.

o   Concentrations in this region were nearly double that of GSQL and YNDQ wines.

o   This region also showed the highest levels of gallocatechin and procyanidin dimers.

  •  Wines from GSQL and YNDQ had the lowest levels of total flavan-3-ols.
  • NXYM wines had the highest levels of epicatechin.

o   These levels were nearly 30 times greater than levels found in YNDQ wines.

  • The highest levels of catechin were found in YNDQ wines.
  • SDYT wines had the lowest levels of catechin.

Flavonols

  • 10 flavonols were found in Chinese wines from the growing regions of study.
  • Highest levels of flavonols were found in YNDQ wines.

o   These levels were nearly 4 times greater than levels found in GSQL wines.

  • YNDQ wines had much higher levels of quercetin derivatives than wines made from other wine regions in China.
  • Higher kaempferol levels were found in NXYM wines.
  • YNDQ wines had the highest levels of dihydroquercentin-O-hexoside, while GSQL wines had the lowest levels.
  • YNDQ wines had higher levels of dihydroquercentin-O-rhamnoside, quercentin-3-O-glucuronide, and myricetin compared to all other regions.
  • Wines from NXYM and YNDQ had higher levels of kaempferol-3-O-glucoside than all other regions.

o   These values were double those found in GSQL and HBCL wines.

Hydroxybenzoic Acids

 

  •  3 hydroxybenzoic acids were found in Chinese wines.
  • Highest levels of total hydroxybenzoic acids were found in SDYT wines, and the lowest levels in NXYM wines.
  • SDYT wines had significantly higher levels of gallic acid, while NXYM wines had the lowest levels.

Hydroxycinnamic Acids

  • 4 hydroxycinnamic acids were found in Chinese wines.
  • GSQL and NXYQY wines showed the highest levels of total hydroxycinnamic acids.

o   These levels were nearly 5 times more than levels found in YNDQ wines.

  • GSQL wines had nearly 9 times more caffeic acid than YNDQ wines and 5 times more ethyl ρ-coumarate than wines made from NXYM and NXYQY grapes.
  • All wines had the highest percentage of gallic acid to total hydroxycinnamic acids.

Stilbenes

  • SDYT had the highest levels of stilbenes, while YNDQ wines had the lowest levels.
  • Trans-resveratrol was the most abundant stilbene in all wines, though was significantly variable between regions.

o   SDYT wines had nearly 7 times more trans-resveratrol than YNDQ wines.

Regional Similarities

  •  Cluster analysis revealed that wines from the Helan mountain of Ning-Xia (NXYM, NXYQY) and GSQL regions were similar in regards to their phenolic composition.
  • Wines from HBCL and SDYT regions were similar in regards to their phenolic composition.
  • The YNDQ wines were different in regards to their phenolic composition than from all other regions.

Conclusions

According to the results of this study, the differences in phenolic composition of Chinese wines in this study indicate that the accumulation of phenolic compounds in grapes is strongly influenced by terroir effects.  Going further, those regions that were geographically closer to one another had wines that were statistically similar to one another in regards to their phenolic composition than regions that were geographically isolated or further away.  NXYQY, NXYM, and GSQL, all of which were similar in phenolic composition, are all located in the drier area of Western China with a cool-warm climate.  HBCL and SDYT were found to be statistically similar to each other in regards to the phenolic content of wines, and were both located in the wetter areas of Eastern China with a warm climate.  Finally, YNDQ was found to be different from all other regions in regards to phenolic composition of wine, and was located on the plateau valley zone of Southwest China with a warm-arid climate.

Overall, these results clearly show terroir effects, and confirm that different regions in China, like other regions around the world, produce grapes that result in wines with statistically different phenolic compositions.  Terroir effects were found to be similar for wines from the Helan mountain of Ningxia and Qilian of Gansu; for wines from Changli of Hebei and the Yantai of Shandong; and finally with the wines from the Deqin of Yunan having significantly different terroir effects from all other regions.

This knowledge of terroir effects in China should give viticulturalists and winegrowers the knowledge necessary for maintaining and caring for vines from each particular region, as well as giving the winemakers knowledge necessary for creating a high quality wine made from grapes with very specific phenolic profiles.  By applying the knowledge gained from this study, grape growing practices and winemaking techniques may be adjusted accordingly in order to optimize wine flavor/aroma quality in China, at the very least with Cabernet Sauvignon grapes.

I’d love to hear what you all think of this topic!  Please feel free to comment below (any unauthorized html tags will be promptly removed).

Source: Li, Z., Pan, Q., Jin, Z., Mu, L., and Duan, C. 2011. Comparison on phenolic compounds in Vitis vinifera cv. Cabernet Sauvignon wines from five wine-growing regions in China. Food Chemistry 125: 77-83.

DOI:  10.1016/j.foodchem.2010.08.039
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!

Posted in Chemistry

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