Monthly Archives: September 2011

Combating Wine Fraud: A New Noninvasive Approach Shows Promise for Testing Authenticity of Wines Without Damage to the Bottle or Wine

Posted on September 29, 2011 by Becca| 7 Comments

Wine fraud is sadly not an uncommon occurrence in the industry, so much so that it has even caught the attention of the Federal Bureau of Investigation (FBI) in the United States.  With rare bottles reaching on average more than $5000, the incentive to create counterfeits is great.  Private collectors and auction houses alike have been implicated in wine fraud, which creates problems with supply and demand in the high-end wine market.  The first solution ever created to help combat wine fraud was to create special bottle labels that would distinguish high-end rare wines from the unauthentic wines.  However, just as a virus can adapt to its environment, the counterfeiters simply found a way around it by simply dumping out the contents of the authentic bottles and replacing it with a poorer quality wine.

The current approaches to analyzing and determining the authenticity of a wine bottle require breaking the cork and seal, which significantly devalue the wine in question, thus making it much less attractive to collectors and investors.  These invasive techniques include ultra-violet/visible infrared spectroscopy, electron and nuclear spin resonance, mass spectrometry, and X-ray absorption.  These methods can often suffer from bottle-to-bottle variation due to glass composition, the requirement of large sample sizes in order to overcome background “noise” issues, or requiring the use of large, bulky pieces of equipment that are not easily moved from place to place.

The study presented here today, which was recently published in the journal Analytica Chimica Acta by chemists at the University of California at Davis, aimed to describe a new method of identifying fraudulent wine bottles, one of which is minimally invasive and easily portable, compared to the current, sometimes unreliable methods.  To be more specific, the method described is based on the dielectric absorption of wine at low (  In theory, the frequency absorption by the various constituents in wine leads to a difference between an electric field that is applied to the wine and the resulting dielectric displacement of the wine.  Basically, what ends up happening is that once the electric field is applied, there is movement of atoms and other molecular ions, a change in orientation of neutral polar molecules, and the polarization of neutral non-polar molecules.  All of these changes are a function of the composition of the wine, which result in a unique “profile” for each wine tested.

The molecular composition of wine varies dramatically due to location, vintage, other local growing conditions, and winemaking techniques, all of which are unique on the molecular level for each and every wine.  Metal ions naturally accumulate in the grapes throughout the growing season, and will be different depending upon the exact vineyard location.  Pollution, sea spray, fertilizers, and pesticides can all introduce metal ions in the grapes as well, which can add to the uniqueness of the molecular signature of the grape and subsequent wine.  Specific vinification techniques can also change the molecular composition of the finished wine, including the particular storage/fermentation vessels, the use of flocculants, pH buffering, alcohol fermentation, malolactic fermentation, the use of glycerol, and the removal of potassium bitartarate from American versus European wines.  The presence of a large variety of molecules, ions, and compounds that vary depending upon growing conditions and vinification techniques change the dielectric response when undergoing analysis using the methods of the authors of this study result in a specific wine signature, or wine fingerprint, which may be used to determine the authenticity of any bottle of wine.

Harley et al, 2011doi: 10.1016/j.aca.2011.06.048

Basically (and when I say basic, I mean really basic), this method works by passing a dielectric frequency across a bottle of wine via a copper electrode, the dielectric response and absorption of which are monitored by another copper electrode at the bottom of the bottle and measured by a computer.  Figure 1 by the authors of this study illustrates the device used to measure this dielectric absorption of intact wine bottles.  The data measured and collected by the computer are then subject to PCA analysis, the results of which provide a unique fingerprint for each wine analyzed.  By knowing the unique fingerprint of authentic wines, and by comparing them to a potential counterfeit wines, it can be determined with accuracy whether or not the wines are authentic or an imposter.

Methods

Due to the intense mathematical, chemical, and physical science presented in the methods of this paper, I will be condensing them and only discussing the most pertinent pieces of information.  Should you require more details, please feel free to ask.  Dielectric measurements were calculated using a suite of equations, of which I’ll skip for now.

Before analysis of specific wines could be done, a set of standards had to be completed, to use as a reference for all other unknown samples.  To create these standards, 16 bottles of Charles Shaw (a.k.a. “Two Buck Chuck”) from Trader Joe’s were drained, rinsed multiple times, and refilled with various solutions of de-ionized water, ethyl alcohol, acetic acid, potassium sulfate, glycerol, and sucrose.  One bottle contained just de-ionized water, to serve as the zero standard, and all other bottles were created using different amounts of the aforementioned components, the means of which are all reported in existing wines.

The high-end wines used for determining their specific fingerprints and establishing a wine fingerprint library were two bottles each of the 1990 Grand Vin Chateau Latour, the 1958 Grand Vin Chateau Latour, the 2002 Opus One, the 1985 Opus One, the 1994 Petrus Pomerol, and the 1979 Petrus Pomerol.

Results/Discussion

The results of this study showed that for every wine in the library, there was a unique dielectric fingerprint that could potentially be used to compare against when testing potential counterfeit bottles.

Harley et al, 2011doi: 10.1016/j.aca.2011.06.048

Looking at Figure 4 from the paper described today, one can see the results of the study in action.  The closed and open squares represent the fingerprints of the 1985 and 2002 Opus One wines; the closed and open diamonds (“lozenges” in the figure heading) represent the fingerprints of the 1958 and 1990 Grand Vin Chateau Latour wines; the closed the open triangles represent the fingerprints of the 1979 and 1994 Petrus Pomerol.  The ‘x’ represents a randomly selected bottle measured on a different day, in order to determine the consistency of the procedure.  That bottle was the 1979 Petrus Pomerol, which due to its’ extreme proximity to the Petrus Pomerol signature acquired on an earlier day, indicates that the procedure is consistent and reliable for identifying the authenticity of wine.

What is required in order to use this procedure for determining the authenticity of wine?  Well, first and foremost, a library of known wines must be available, and the particular wine in question must have had an authentic bottle analyzed previously in order to have something to compare it against.  Most other methods of analyzing authenticity are much the same (i.e. a sommelier must have actually tasted the wine in the past to know if what they are tasting is in fact the same wine), so this is not seen as a drawback.

One of the results of this research was that this method appears to be temperature dependent.  For example, if the library wine was tested at room temperature, then the unknown wines must also be sampled at room temperature.  It must be noted in the library what temperature the wines were measured at, in order to determine the proper temperature of which to measure the unknown wines in question.

The next step from this research is to go ahead and create an extensive library with the fingerprints of as many authentic high-end wines as possible.  Since this method does not damage the wine bottle or the wine itself, this should be relatively straight forward, provided collectors are willing to loan their bottles to scientists.

In conclusion, the results of this study show that a new noninvasive, nondestructive technique for determining the authenticity of wine bottles has been established.  Provided the fingerprints are available for the authentic versions of the wine in question, this new method may prove to be the superior choice to analyzing potential counterfeit wines, thereby decreasing the frequency of wine fraud across the globe.

I’d love to hear what you all think about this topic!  Do you have any personal experience with wine fraud?  Feel free to leave any comments below!

Source:  doi: 10.1016/j.aca.2011.06.048
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

Tagged , , , , ,

The Next Step Toward a “Super Wine”: Fortification with Resveratrol May Not Affect Sensory Characteristics of Some Wines

Posted on September 27, 2011 by Becca| 2 Comments
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“Functional foods” or “superfoods” are growing increasingly popular among consumers looking for a healthier alternative to their current diet.  Functional foods, which are often enhanced or fortified with compounds designed to better ones’ health (i.e., antioxidants), intend to provide increased physiological benefits to those that consume them, thus potentially providing more of a health benefit than “normal” food would provide.  In general, it has been shown that people are more willing to purchase functional foods than the comparable food items that have not be enriched in any way.  The use of wine as a functional food, though a relatively young idea (within the past three years or so), is no different in regards to consumer willingness to pay preferences.  In fact, The Academic Wino discusses a paper previously regarding this exact topic, finding that participants in that particular study would be willing to pay $8.39 USD ($5.89 Euros) more for resveratrol-enriched red wines than red wines not enriched with the compound (read that review here).

Resveratrol, which is a plant-derived phenol that has been linked to a wide variety of health benefits, is found in many species, including peanuts, blueberries, bilberries, and grapes.  It has been shown to protect against a wide variety of ailments, including diabetes, colon and breast cancers, cardiovascular disease, and neurological disorders.  The health benefits of resveratrol have been most studied in grapes, and also the wine produced from those grapes.  Found in the skins of grapes, it functions in the plant to act as an antioxidant and antibiotic, particularly when in a stressful environment (i.e. when under attack by Botrytis cinerea).  Recently, the idea of creating a “functional wine” that is fortified/enriched with resveratrol, has become increasing enticing for those more health-conscious individuals.

After vinification of the grapes, the average red wine contains about 7mg/L of resveratrol, with rosé wines coming in second at 2mg/L, and finally white wine following with 0.5mg/L.  Rosés and white wines contain significantly less resveratrol on average than red wines, due to the lack of skin contact with the juice, however, vinification techniques which increase the maceration type of white and rosé wines have shown to result in an increase in total resveratrol, which mirrors that of red wines (to see The Academic Winos’ most recent review of this topic, click here).

Increased maceration time is not the only way to increase resveratrol levels in wine.  Techniques such as pomace pressing, malolactic fermentation, thermovinification, postharvest controlled UV-radiation, and short, anoxic treatments with dry nitrogen all work to increase resveratrol levels in the finished wine.  Some techniques may have the opposite effect, and work to decrease the levels of resveratrol in the finished wine.  These techniques include fining, filtering, and natural variations in different grape varieties.  By increasing resveratrol, it has been shown that the levels of other phenolic compounds increase as well, such as (+)-catechin and (-)-epicatechin, which result in the potential of higher bitterness in the wines, and thus lower consumer acceptance of the finished wine.

As a result of this change in other phenolic compounds after the increased resveratrol concentrations due to vinification techniques, scientists have been looking toward other methods that may not have this negative effect on wine aroma and flavor.  Two methods of particular interest are first genetic restructuring, such that the plants naturally produce higher levels of resveratrol in the skins of grapes, and second direct enrichment of resveratrol into the finished wine.  Scientists have already created wines that use the enrichment method, however, very little is known about the resveratrol concentration and stability over time and aging.  Therefore, the overall goal of the study reviewed today, which was recently published in the Australian Journal of Grape and Wine Research, was to measure changes in resveratrol levels in wine over time, while simultaneously measuring sensory characteristic (aroma/flavor) and changes therein.  This is reported to be the first study of its’ kind to follow the chemistry and sensory characteristics of resveratrol-enriched wines over time.

Methods

Wines were produced from commercial kits of juice concentrates.  The red Cabernet Sauvignon and the white Riesling were created.  Juice was chaptalised using super fine sucrose to achieve an alcohol level of 14%.  Juices were rehydrated and inoculated with the yeast strain EC1118, following the manufacturers’ instructions.  Fermentation occurred in stainless steel tanks, with Cabernet Sauvignon wines undergoing an oak chip treatment (Hungarian oak, medium plus) from days 2 through 8 to yield aroma and flavor results similar to commercially available Cabernet Sauvignon wines.  Free SO2 levels were adjusted to 25-30mg/L, and then cold stabilized.  After cold stabilization, wines were filtered and the resveratrol treatments applied.  Three treatments of 0mg/L resveratrol (control), 20mg/L resveratrol, and 200mg/L resveratrol were added to the wines.  SO2 levels were once again adjusted accordingly, and the wines were subsequently bottled.

Basic wine chemical analysis were performed, including measurements of pH, titratable acidity (TA), free and total SO2, ethanol, antioxidant capacity, and resveratrol levels.  Chemical analyses were performed on two bottles per treatment in duplicate, at bottling, 6, 18, 31, 44, and 58 weeks post bottling.

Sensory analysis (aroma, flavor, and visual) was performed by faculty, staff, and students of Brock University’s Cool Climate Oenology and Viticulture Institute in Ontario, Canada.  Triangle tests were performed using these untrained panelists at 6 and 32 weeks after bottling.  Cabernet Sauvignon and Riesling wines were analyzed in separate sessions, with two sessions for each wine style.  For more detailed description on the exact methodology of these sensory analysis sessions, please feel free to ask.  In lieu of space in this post, I will omit this information for now until prompted.  I do have relatively detailed information at the ready, should you require it for your interpretation of the results.

Descriptive analysis of wines was performed at 16 and 40 weeks after bottling.

Results

Basic Wine Chemistry

  •       Titratable acidity (TA)

o   TA was significantly higher for the 20mg/L and 200mg/L treatments in Riesling wines compared to 0mg/L control wines at 18, 31, and 44 weeks after bottling.

o   TA was only slightly different for Cabernet Sauvignon wines across all treatment levels and all times.

  •       Free SO2

o   Free SO2 concentrations decreased over time for all treatments.

o   Free SO2 concentrations were not significantly affected by resveratrol concentrations, though small differences were noted for Riesling wines at 58 weeks and Cabernet Sauvignon wines at 31 and 58 weeks after bottling.

  •       pH

o   There was no effect of resveratrol treatment on pH in all wines.

  •       Antioxidant Capacity (AC)

o   For most time points, AC was higher for 20mg/L and 200mg/L resveratrol treatments in Cabernet Sauvignon compared to the 0mg/L control.

o   At all time points, AC was significantly higher for 200mg/L resveratrol wines in Riesling compared to the 0mg/L control.

  •       Wine Color and Phenolics

o   Wine color hue and color density was significantly different in 20mg/L and 200mg/L resveratrol treated Cabernet Sauvignon wines than the control, with color density increasing and wine color hue decreasing with increasing levels of resveratrol enrichment.

§  This suggests resveratrol treatment is associated with a higher ratio of red to yellow/brown colored pigments.

o   Total red pigments in Cabernet Sauvignon decreased significantly for each treatment over time, with the color shift from red/blue to yellow/brown.

o   Total hydroxycinnamate and phenolic concentrations were significantly higher in resveratrol enriched Riesling wines (200mg/L displaying the highest levels).

o   Browning and pinking of Riesling wines increased over time for all treatments, with more hue change occurring with the highest level of resveratrol enrichment.

  •       Resveratrol

o   After an initial drop at 6 weeks after bottling, trans-resveratrol was stable over the remaining 58 week aging period.

§  This initial drop may have been due to resveratrol and other phenolic compounds binding to themselves or other phenolic compounds.

o   Cis-resveratrol was detected in both Cabernet Sauvignon and Riesling wines, with the highest concentration occurring at week 6 after bottling.  After 6 weeks, cis-resveratrol levels dropped below the level of detection for this analysis.

Sensory Analysis

  •       6 weeks after bottling:

o   Significant differences in aroma/flavor were found for Riesling wines treated with 200mg/L resveratrol compared to the controls.

o   No differences in aroma/flavor were found for Riesling wines treated with 20mg/L resveratrol compared to the control, nor were any difference in aroma/flavor found in any of the Cabernet Sauvignon treatments compared to the controls.

  •       32 weeks after bottling:

o   Significant differences were found for bitterness in Riesling between the 200mg/L treatment compared to the control and the 20mg/L treatment compared to the 200mg/L treatment.

o   No significant differences were found in aroma/flavor in Riesling between the 20mg/L treatment and the control treatment.

o   No significant differences were found in aroma/flavor in any Cabernet Sauvignon treatments.

o   Significant differences in color were found for 20 and 200mg/L Cabernet Sauvignon treatments versus the control, and 200mg/L Riesling versus the control.

Descriptive Sensory Analysis

Figure 3 from Gaudette and Pickering, 2011

doi: 10.1111/j.1755-0238.2011.00144.x

 

  •       16 weeks after bottling:

o   The 200mg/L resveratrol treatment in Riesling wines rated higher in bitterness than the control wines.

o   Floral and vegetal aromas were higher in 20mg/L resveratrol Riesling wines than the controls.

  •       40 weeks after bottling:

o   The 200mg/L resveratrol treatment in Riesling wines rated higher in bitterness than both the 20mg/L and control treatment wines.

  •       As a reminder, there were no significant differences in aroma/flavor descriptors in any of the Cabernet Sauvignon wines at any time point after bottling.

Conclusions

This study is the first of its’ kind (to our knowledge) that follows the basic wine chemistry and stability of resveratrol in wines over time, with the inclusion of a sensory analysis.  The results of the study show that resveratrol appears to be stable for at least 58 weeks, after which the stability is unknown to the end of the allotted experimentation time.  The results also provide evidence to support the hypothesis that enrichment of wine with resveratrol may provide increased antioxidant protection for wines over some period of aging time.  Resveratrol-enriched wines stored up to approximately one year may provide greater health benefits to consumers than wines not enriched in the powerful antioxidant. Of course, in order to truly determine if health benefits are further increased due to resveratrol enrichments, the proper medical study would need to be completed.

Enrichment of Cabernet Sauvignon wines did not appear to alter the aroma/flavor of the wines.  This could be a varietal effect, or it could be due to the oak chip treatment during fermentation.  It is possible that the oak treatment may have masked any potential sources of bitterness, and the fact that this particular varietal is already associated with a higher level of bitterness compared to a white wine may have made any differences more subtle and difficult to distinguish.  More varietals of varying levels of initial bitterness should be analyzed to see if this lack of an effect is consistent across many varieties, or if it is Cabernet Sauvignon-dependent.  Higher bitterness was detected in Riesling wines treated with resveratrol, which may have been more noticeable due to the fact that Riesling wines have a naturally low level of bitterness to begin with and any changes would be much more noticeable than they were in Cabernet Sauvignon.

The results of this study provide important information on resveratrol-enriched wines, and provide a launching point for those wishing to create this type of “functional food”.  For some wine varietals, such as Cabernet Sauvignon, it appears that resveratrol enrichment does not have a negative influence on the aroma/flavor of the wine.  For other wine varietals, such as Riesling, the influence on the aroma/flavor may be less desirable for consumers.  Some varietals may require some flavor tweaking (such as Riesling), while other may be good to go to the consumer without any further modifications.  While there may not be a simple recipe for creating a resveratrol-enriched “super food”, the results of this study show promise that a wine enriched in resveratrol may not only be good for you, but may also have no negative impacts on the aroma/flavor of the resulting wine (varietal and vinification technique-dependent).

Do you have any experience functional foods or functional wines in any way?  Do you have any comments/questions?  I’d love to hear from you!  Please feel free to comment below!

Source: doi: 10.1111/j.1755-0238.2011.00144.x

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 Enology

Tagged , , , , ,

Wine Consumption May Play a Protective Role in Neurodegenerative Disease

Posted on September 22, 2011 by Becca| 2 Comments
http://t2.gstatic.com/images?q=tbn:ANd9GcTc
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Essential tremor is a neurological syndrome, which results in involuntary shaking, usually noticed most in the hands.  This type of tremor is the most common, with a prevalence of about 0.9%,  and occurs more frequently past the age of 65, when the prevalence rises to about 4.6%.  The exact cause of essential tremor is unknown, though it could be caused by problems with the nerves that control particular muscles.  Essential tremor alone is more of an inconvenience than a serious health threat; however, it has also been known to occur along with other neurological disorders, such as dystonia, Parkinson’s disease, and other neurological conditions that can lead to more serious health concerns.

Genetic factors may play a role in whether or not an individual displays essential tremor, or a more serious neurological disease such as Parkinson’s, though it is likely that environmental factors may play a role as well.  Studies have shown conflicting results in regards to protective effects of various environmental stimuli on essential tremor symptoms, with some showing protective effects of cigarette smoking and caffeine intake, while others showing just the opposite. 

The study presented today, though brief in length, aimed to address the question of whether or not these environmental stimuli have any effect on the symptoms of essential tremor.  Published in the journal Movement Disorders earlier this spring, this study evaluated the role of cigarette smoking, coffee consumption, and alcohol consumption (specifically, wine drinking) on essential tremor in adults.

Methods

Study Subjects

The individuals enrolled in this study were patients from six Movement Disorder centers in central-southern Italy (Bari, Catania, Catanzaro, Grosseto, Messina, and Naples).  Those diagnosed with essential tremor were eligible for this study.  Three unrelated healthy controls (not affected by any neurological disease) for each essential tremor subject were also enrolled.  Controls were matched to essential tremor individuals by age and sex.  Most of these controls were recruited from the spouses of those with essential tremor, or those who accompanied the essential tremor patient at the clinic.  All participants, those in both the control and essential tremor groups, underwent a standard neurological examination.

Interviews/Questionnaires

All study participants underwent a face-to-face interview and completed a standardized structured questionnaire.  The questionnaire was broken down into different sections, including a section for demographics, one for clinical information regarding essential tremor and other neurological diseases, and one for environmental factors such as smoking, drinking coffee, and drinking alcohol.  For the cigarette smoking factor, questions involved how many cigarettes smoked per day, and the number of years smoked.  For the coffee consumption factor, questions involved the duration and the number of cups consumed per day.  Finally, for the alcohol consumption factor, questions involved the duration and the type of alcohol consumed, and whether they could be classified as “never drinkers”, “occasional drinkers”, or “regular drinkers” (current or quit).

Results

  •       83 essential tremor patients participated in this study.

o   38 were men and 45 were women, with a mean age of 68.2 +/- 8.6 years.

  •       245 matched controls participated in this study.

o   113 were men and 132 were women, with a mean age of 68.4 +/- 9.7 years.

  •       The mean age at the onset of essential tremor was 53.2 +/- 17.9 years, with mean disease duration of 12.6 +/- 13.2 years.
  •       48.1% of essential tremor patients reported a positive family history of the disease.
  •       Cigarette smoking and coffee consumption were not associated with essential tremor.
  •       Due to the low numbers of regular beer drinkers (0 essential tremor patients, only 6 controls) and regular liquor drinkers (only 2 essential tremor patients and 3 controls), only wine consumption was considered and analyzed (26.8% of essential tremor patients and 38.8% of controls).
  •       There was a highly significant negative association between wine drinking and essential tremor (i.e., drink more wine, experience fewer tremors).

o   This association became even stronger after controlling for family history of essential tremor.

o   There was a significant decreasing risk of essential tremor with increasing number of glasses of wine per day, with a greater risk reduction (of about 86%) for patients consuming more than 3 glasses per day.

  •       Wine consumption preceded the onset of disease (in all cases): the mean duration of wine consumption was 48.9 +/- 12.3 years, and the mean disease duration was 12.8 +/- 13.2 years. 

o   86.4% of the essential tremor patients stated wine consumption started more than 30 years before the onset of disease (and none had quit drinking).

  •       90% of the subjects that were categorized as regular drinkers consumed up to 4 glasses per day (considers light to moderate consumption).

Discussion and Conclusions

Unlike some studies, this study found that cigarette smoking did not show protective or damaging effects against essential tremor.  Similarly, coffee consumption also showed no effect on essential tremor symptoms.  Interestingly, however, was that wine consumption had a highly significant negative association with essential tremor.  Basically, the more wine one consumes, the less severe the symptoms of essential tremor are exhibited.  Of course, there wasn’t enough information/data in this study to rule out the possibility of too much alcohol consumption, which in other systems have shown possible harmful effects of drinking too much, regardless of whether or not the same substance shows protective effects in more moderate amounts.

Many other studies have found that resveratrol, along with many other polyphenols, have protective cardiovascular characteristics, as well as antioxidant activities in consumers of red wine.  The latter characteristic could potentially be involved in this reduction of essential tremor in wine consuming patients.  In many neurodegenerative diseases, not unlike Parkinson’s, it has been shown that there is an excess of reactive oxygen species present in the brain.  Polyphenols in red wine (i.e., resveratrol) may act in an antioxidative manner to reduce the amounts of free radical oxygen species in the brain, thus reducing the symptoms of the disease.  Prolonged exposure to red wine could create a more oxygen-stable environment in the brain, thus potentially delaying the onset of neurological disease, or at the very least reducing the symptoms.

Though these types of studies sometimes produce results that are slightly bias, the high level of significance in this particular study and the extreme length of time from the onset of wine consumption to the onset of essential tremor indicate that the results of this study show promise to those affected by this neurological disease.  Of course, more detailed studies would need to be done, but the initial research here is hopeful.  I would like to see a study that is able to include all types of alcohol, to get a better sense of whether it is the alcohol itself playing a protective role, or if it is in fact the polyphenols in red wine that are giving these protective results.  I would also like to see a study that includes essential tremor patients, in addition to patients experiencing various stages of Parkinson’s disease.  If red wine helps with essential tremor, could it help alleviate some of the symptoms of Parkinson’s disease as well?  I’ll be keeping my eye out…

How about you all?  Do you have any experience with essential tremor or other neurological diseases?  Have you noticed if red wine consumption helps with your symptoms? 

Please feel free to leave any comments below!

Source:  10.1002/mds.23603
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 Health

Tagged , , , ,

Role of Melatonin in Grapes: Joining Resveratrol and Anthocyanins as the Trifecta of Healthy Wine Components

Posted on September 20, 2011 by Becca| 4 Comments
 
 
http://www.flickr.com/photos/michaelreuter/4568203319/
There have been countless studies investigating the role of melatonin in human and other animal systems, however, very few studies have studied the role of melatonin in plants.  In animals, melatonin is highly involved in the regulation of physiological cycles, including the sleep cycle, which is dependent upon the light and dark cycle.  Not only is melatonin important in the sleep cycle of animals, but it also plays important roles as an antioxidant, inhibitor of some cancers, and can be beneficial for some neuronal disorders. 

The studies that have been done on plants, though fewer in number than in animal models, have found melatonin present in the roots, leaves, flowers, fruits, and seeds.  Many plants used for medicinal purposes have been found to have high levels of melatonin.  It is speculated that melatonin may act as an antioxidant in plants to protect them against environmental oxidative stress and perhaps even control flowering, but more studies need to be conducted in order to get a clearer picture of the physiological role of melatonin in plants.

Since melatonin is found in the fruit of other plants, it is thought that it may also be present in grapes.  The health benefits of melatonin, if present in grapes, could act synergistically with the polyphenols (i.e. resveratrol) and other health beneficial compounds in grapes, which would explain in part some of the widely studied health benefits of wine.  One study was able to find melatonin present in Vitis vinifera grapes, though the levels varied across varieties and winemaking techniques.  Extremely little is known about the role melatonin plays in grapes, and almost nothing is known about its abundance during the day and night.

The study under review today is one of the very first to examine these questions.  Published this spring in the Journal of Pineal Research, the authors goals were three fold.  First, they sought to test whether melatonin levels in Vitis vinifera grape skins fluctuate during the day; second, to examine whether or not daylight itself was responsible for changes in melatonin levels throughout the day; and finally third, whether there was a time of day that melatonin and other polyphenols levels were all at a maximum, in order to potentially create a more healthy bottle of wine.  Though brief, this study provides fascinating insight on the role of melatonin in grapes, and provides an interesting time schedule for harvesting grapes, in order to create the most health-beneficial wine possible.

Methods

Grapes were harvested during the 2010 season at a commercial vineyard of Malbec grapes (selected clones without rootstock), in sandy soils and drip irrigated plots, which was located in Gualtallary, Tupungato, in the province of Mendoza, Argentina.  The 11-year old vines were trained on a vertical trellis and pruned as Guyot.  Rows were arranged in a north-south direction, and were spaced 2 meters apart, with 1.2 meters between plants in each row.  The vines were protected by antihail nets, which were made from black polyethylene, which produced about 17% shade on the plants.

The experiment was set up as a randomized complete block design (for those not familiar with statistical methods, this type of a design is fantastic), with each row acting as a block.  Grape sampling was completed on April 26th, 2010, which coincided with the commercial harvest date.  In each block (row), 50 grapes were collected from 10 clusters at different times of the day (and placed in black nylon bags to avoid light exposure after harvest).  Times of harvest were 02:00, 06:00, 09:30, 13:00, 17:30, and 23:30 hr.  All samples were kept away from light and on ice while in the field, and upon arrival in the laboratory, were subsequently frozen and stored at -18oC until further analysis.

For the light exclusion treatment, clusters were covered with black ethylene vinyl acetate (EVA) in the inner side, and a white paper covering this EVA in order to avoid an increase in cluster temperature throughout the day.  Temperature and photosynthetic active radiation was measured throughout the day.

Melatonin was measured via HPLC-ESI-MS/MS.  Total phenolic compounds were measured via UV-Vis.  Also measured during this experiment was malondialdehyde, which is a product of lipid perioxidation.

Results

  •       Melatonin levels in the skins of Malbec grapes were low during the night, and reached a strong peak at dawn.  Throughout the day, melatonin levels decayed to undetectable values at noon and during the afternoon.

o   In humans, melatonin (which is released by the pineal gland) increases in the serum during the night, and decreases during the day.

o   For the grapes that were kept in the dark by EVA covering, melatonin levels were higher than those exposed to natural sun radiation.

§  Temperatures of covered versus not covered grapes showed no significant differences.

  •       Anthocyanins and polyphenols levels did not fluctuate during the day at harvest.
  •       Malodialdehyde (MDA), an indicator of oxidative damage, fluctuated during the day and night, and reached a maximum level at 17:30 hrs.

o   MDA minimums coinciding when melatonin levels were detectable in grapes.  Since MDA levels were lowest (i.e. least damage done) when melatonin was present, it may suggest a protective antioxidant role for the grapes and plant.

§  This thought it further supported by the finding that MDA levels in the covered clusters were significantly lower than those clusters exposed to natural radiation.

Discussion and Conclusions

Despite being a relatively short study, it proved to be the very first to show that melatonin levels in grapes fluctuate during the day and night in the Malbec variety under field conditions.  These fluctuations could be a result of some sort of circadian rhythm for the plant, with the lowest levels occurring during the afternoon hours of the day.  In addition to a sort of circadian rhythm, this study also showed that melatonin may play an important antioxidant role for the grapes.  Melatonin levels are seemingly replenished at night, and act as a protector against UV rays during the day, which cause an overall degradation/decrease in melatonin levels.  If there was no melatonin replenishment in the evening/early morning hours, there would be no protection against UV damage during the day, and the fruit would not survive.  This line of thought may be supported by the results of the light exclusion study, in that those clusters that were covered during the day showed higher levels of melatonin than those that were exposed to natural radiation.  Since there was significantly less UV radiation on the covered clusters, very little melatonin was degraded.  This suggests an antioxidant role for melatonin in grapes.

This study was also able to show that other compounds, such as polyphenols and anthocyanins, do not fluctuate during the day.  If polyphenol and anthocyanin levels do not change throughout the day, then the best time to harvest is clearly when melatonin levels are at their highest.  Therefore, in order to create the most health beneficial wine, in regards to cardiovascular benefits and antioxidative/anticancer benefits, grapes should be harvested when melatonin levels are at a maximum, thereby maximizing all three health beneficial components.  In this example, in order to get a wine rich in polyphenols, anthocyanins, and melatonin, the ideal time to harvest would be at dawn.

As a side note:  I wonder if this is part of the reason why wine makes me more sleepy than say if I were drinking beer or spirits.  I can have the same amount of alcohol, but with wine, I often feel like lying down and taking a nap.  The presence of melatonin may also function as a sleep-inducing agent as well (not considering the depressant characteristics of the alcohol portion of the beverage), though this is 100% speculation on my part and has yet to be studied.

This study provides results that are “groundbreaking in viticulture”, and provide insight into the mechanisms behind melatonin fluctuations in plants.  Much more research needs to be completed; however, this study provides a solid baseline by which future research should be measured against.  This study is beneficial not only for viticultural applications, but for other plants as well which may be useful for their nutritious and potentially pharmaceutical properties.

I’d love to hear what you all think about this topic.  Please feel free to comment below!

Source: Doi: 10.1111/j.1600-079X.2011.00884.x

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