Tag Archives: wine literature review lightning round

Wine Literature Review Lightning Round: 5th Edition

Posted on April 26, 2013 by Becca| Leave a comment

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There’s no way one single person can possibly review every single piece of peer reviewed literature related to wine that is published every day. This series presents multiple new papers (within the past year or two) in one post by briefly summarizing the research and linking to the source in order for you to pursue further if you’re interested. If there is enough reader interest, I can review any of the papers introduced to you in this post in a more critical assessment.

VITICULTURE/ENOLOGY

“Changes in sour rotten grape berry microbiota during ripening and wine fermentation”. This article, published in 2012, aimed to determine the community structures of yeasts, lactic acid bacteria, and acetic acid bacteria in healthy grapes and grapes afflicted with sour rot, and how the winemaking process does or does not change these populations. Using healthy and sour

NOBEL ROT (Not sour rot): Photo by davitydave (Flickr: IMG_0556.JPG) [CC-BY-2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

rotten Trincadeira grapes from an experimental vineyard in Portugal, the researchers determined the microbiological composition of the grapes as well as the wines created from these grapes. Wines were made with either 100% healthy grapes, or with 70% healthy grapes plus 30% sour rotten grapes.

Results showed that sour rotten grapes showed significant increases in their populations and species diversity of yeasts and acetic acid bacteria counts, while lactic acid bacteria populations were low for both sour rotten grapes and healthy grapes. The bacterial species Acetobacter orleaniensis and Acetobacter syzygii were present only in sour rotten grapes. The yeast species Dekkera bruxellensis and Oenococcus oeni were found only after primary fermentation in all wines, and after malolactic fermentation, racking, and SO2 addition, the only yeast species found were Trigonopsis cantarellii and Saccharomyces cerevisiae (in all wines). The concluding results were that there are significant microbiotic changes in grapes that are afflicted with sour rot, with potential implications for early detection in the field for treatment or sorting purposes prior to winemaking.

Source: Barata, A., Malfeito-Ferreira, M., and Loureiro, V. 2012. Changes in sour rotten grape berry microbiota during ripening and wine fermentation. International Journal of Food Microbiology 154: 152-161.

CONSUMER PREFERENCES

“What matters to consumers of organic wine?”. This article, published in 2012, aimed to determine how important the distinction of “organic” of a wine is to consumers, and what other attributes of the wine are important to those that consume organic wine. To examine this issue, surveys were sent out to around 400 Swiss wine drinkers, which asked questions related to the judgment of different wine labels, how the image and make-up of an organic wine label influences their purchase behavior, and questions related to demographics of each survey participant.

The results showed that the most important attribute for these Swiss wine drinkers was price and country of origin (they preferred French over Swiss wine). The “organic” attribute was less important than price and country of origin; however, it was more important than the color of the wine. Those participants that considered themselves healthy, as well as urban residents and female consumers were more likely to consume organic wine than their other fellow participants. From these results, the authors suggest the Swiss wine market should focus their advertising on the healthy image of wine, as well as direct the marketing toward urban women in order to maximize likelihood of purchase for organic (and other) wines.

Source: Mann, S., Ferjani, A., and Reissig, L. 2012. What matters to consumers of organic wine? British Food Journal 114(2): 272-284.

HEALTH

“The antimicrobial effect of wine on Bacillus cereus in simulated gastro-intestinal conditions”. This article, published in 2012, aimed to determine if wine could protect against Bacillus cereus infection (i.e. results in food poisoning) in the human digestive system, using a simulated experimental design. Survival of Bacillus cereus when exposed to wine was first testing in inoculated TSB media (i.e. not simulated human conditions). Next, survival of B. cereus when exposed to wine was tested in simulated human digestive system conditions, by creating an environment very similar in chemistry to the inside of the human digestive system.

Results from the first test showed that B. cereus spores were resistant to wine exposure, however, B. cereus cells in the vegetative state were highly sensitive to wine and were significantly reduced when exposed to wine. The authors broke down the components of the wine to determine which components were responsible for this decrease in vegetative B. cereus cells, and found that wine

Photo by Flickr user Evil Erin

organic acids reduced B. cereus vegetative cells, which wine phenolic compounds had no effect on B. cereus vegetative cells. Similar results were found in the human digestive system simulation experiment, with wine (total wine, not just wine parts) significantly reducing B. cereus vegetative cells and somewhat reducing B. cereus spores. The authors concluded that wine therefore may have a protective/antimicrobial effect against the food poisoning causing B. cereus, and that it is the organic acids in the wine (and not the polyphenols) that seem to be providing that protection.

Source: Vaz, M., Hogg, T., and Couto, J. 2012. The antimicrobial effect of wine on Bacillus cereus in simulated gastro-intestinal conditions. Food Control 28: 230-236.

Posted in Literature Review Lightning Round

Tagged consumer preferences, enology, viticulture, wine and health, wine literature review lightning round, wine research

Wine Literature Review Lightning Round: 4th Edition

Posted on March 18, 2013 by Becca| 4 Comments

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Normally, I save this series for Fridays, however, I was surprised by a marriage proposal (of which I said yes!) by my now-fiancé this weekend and didn’t end up having time to write anything else Enjoy this post a few days early!

There’s no way one single person (even if that person is The Academic Wino!) can possibly review every single piece of peer reviewed literature related to wine that is published every day. This series presents multiple new papers (within the past year or so) in one post by briefly summarizing the research and linking to the source in order for you to pursue further if you’re interested. If there is enough interest, be it through comments or emails, I can review any of the papers introduced to you in this post in a more critical assessment.

WINEMAKING

“An assessment of using ground thermal inertia as passive thermal technique in the wine industry around the world”. This article, published in 2012, aimed to use a mathematical modeling approach to confirm the benefits of using underground cellars for aging wine, and to promote the use of this type of cellar when constructing new wineries. Basically, the model employed during this analysis used thermal inertia (i.e. how temperature moves in a given medium or space) of the ground in order to provide protection to the wines during the aging process. The characteristics of these underground cellars allow for good ventilation as well as good temperature control for the wines during the aging process.

By Philip Larson (originally posted to Flickr as DSC02022) [CC-BY-SA-2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons

According to the model results, the inputs of which were based on real underground wine cellars in Spain, the ideal temperature for storing wine is easily reached inside these underground cellars without the need for supplemental air conditioning. Eliminating the need for air conditioning is beneficial for multiple reasons, one being the savings on one’s electric bill, while the other being a savings for the environment in regards to a reduced carbon footprint. Finally, according to the authors of this study, the model the used in this analysis could be helpful for those designing or constructing new wine cellars, which based on the specific measurements and layout planned, could estimate the indoor temperature of the cellar and possibly allow for infrastructure changes if need be prior to completion of the facility if the temperature based on current specs was not up to acceptable standards.

Source: Mazarrón, F.R., Cid-Falceto, J., and Cañas, I. 2012. An assessment of using ground thermal inertia as passive thermal technique in the wine industry around the world. Applied Thermal Engineering 33-34: 54-61.

VITICULTURE

“Floral, spicy and herbaceous active odorants in Gran Negro grapes from shoulders and tips into the cluster, and comparison with Brancellao and Mouratón varieties”. This paper, published in 2012, aimed to examine the aromatic characteristics of Gran Negro grapes, and to specifically test if grapes from different parts of the cluster (shoulders and tips) would yield different aromatic compounds that could be taken advantage of when trying to create a unique wine in a highly competitive market. GC-MS spectroscopy was used to determine the aromatic chemical profile of the grapes from both the shoulders and the tips of the clusters.

The results of the study showed significant variation in aromatic compounds of grapes, depending upon where in the cluster the grape was located. For those grapes located at the tip of the cluster, volatile phenols and aromatic alcohols were 2 and 15 times higher in the flesh of the grape than in the skins, respectively, whereas for those grapes located at the shoulder of the cluster, volatile phenols were 2 times higher in the skins of the grapes compared with the flesh. Also, aldehydes and C6 alcohols were 4 and 3 times higher in the skin than in the flesh for those grapes located at the tips of the clusters. C6 alcohols were found to be 40% lower in the tips than in the shoulders.

Overall, this study showed that there is significant variation in the volatile composition of grapes, depending upon where in the cluster the grape is located, which could allow winemakers to create even more unique wines which could give them a market advantage in this competitive industry.

Source: Noguerol-Pato, R., Gónzalez-Barreiro, C., Cancho-Grande, B., Martínez, M.C., Santiago, J.L., and Simal-Gándara, J. 2012. Floral, spicy and herbaceous active odorants in Gran Negro grapes from shoulders and tips into the cluster, and comparison with Brancellao and Mouratón varieties. Food Chemistry 135: 2771-2782.

“RECYCLING”/ENVIRONMENTAL SCIENCE

“Wine grape pomace as antioxidant dietary fiber for enhancing nutritional value and improving storability of yogurt and salad dressing”. Grape pomace has already been shown to improve the shelf life and/or nutritional quality of many food products, including chicken, hotdogs, and green tea. This study, published in 2013, aimed to examine if grape pomace added to yogurt and salad dressing could be beneficial in this same manner, and whether or not consumers would actually enjoy the taste of these products after the pomace was added. Dried grape pomace powder was added to yogurt, Italian salad dressing, and Thousand Island salad dressing and stored for 3 weeks at 4oC.

By Tricia (Flickr: saladdressing) [CC-BY-SA-2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons

Results showed that adding grape pomace to all samples resulted in a 35-65% reduction in peroxide values, indicating the potential benefit of grape pomace as a preservative in all three products. The samples also showed dietary fiber levels of 0.94-3.6%; total phenolic content of 958-1340 mg gallic acid equivalent/kg product; and DPPH scavenging activity (i.e. antioxidant capacity) of 710-936 mg ascorbic acid equivalent/kg product. Sensory analysis revealed the products with grape pomace added were nearly universally accepted as “likable”. Overall, the study results indicated that grape pomace could be a good additive to yogurt and salad dressing in order to prolong shelf life and improve the nutritional content of the products.

Source: Tseng, A., and Zhao, Y. 2013. Wine grape pomace as antioxidant dietary fiber for enhancing nutritional value and improving storability of yogurt and salad dressing. Food Chemistry 138: 356-365.

I’d love to hear what you all think about any or all of these topics! Please feel free to leave comments!

Posted in Literature Review Lightning Round

Tagged environment, grapes, recycling, viticulture, wine literature review lightning round, winemaking

Wine Literature Review Lightning Round: 3rd Edition

Posted on March 1, 2013 by Becca| Leave a comment

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VITICULTURE:

“Long-Term Effects of Mechanical Winter Pruning on Growth, Yield, and Grape Composition of Barbera Grapevines”. This article, published in 2011, aimed to compare mechanical pruning of grapevines to hand pruning, and whether one or the other fared better for the grapes the following year in regards to growth, yield, and grape quality. Barbera vines were examined over a 5 year period and were subject to either manual pruning by hand, or mechanical pruning with their a light manual follow-up for a severe manual follow-up.

The results showed very few (if any) differences between manual hand pruning and mechanical pruning. Specifically, yield per vine, cluster weight, bud fruitfulness, and grape composition were similar between the different treatments. The only minor difference was a slight decrease in anthocyanin content in the mechanically pruned vines, which was insignificant (i.e. they were statistically the same for all treatments). The take-home from this study, according to the authors, was that since mechanical pruning yielded grapes that

By Mark Smith [CC-BY-2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

were nearly identical in yield, composition, and quality compared with hand pruning, it may be of economic benefit to the vineyard to pursue mechanical pruning strategies. By using mechanical pruning, labor demand in this experiment decreased by 70%. Of course, certain vineyards can’t use mechanical pruning equipment due to their steep slopes and tricky terrain, so these results aren’t necessarily applicable to all vineyards.

Source: Gatti, M., Civardi, S., Bernizzoni, F., and Poni, S. 2011. Long-Term Effects of Mechanical Winter Pruning on Growth, Yield, and Grape Composition of Barbera Grapevines. American Journal of Enology and Viticulture 62(2): 199-206.

ENOLOGY:

“Effect of co-winemaking in phenolic composition, color and antioxidant capacity of young red wines from La Mancha region”. This article, published in 2012, examined the effects of the co-winemaking technique on phenolic composition (as well as color and antioxidant capacity) of some Spanish red wines. Several 1:1 blends of two different Spanish red grape musts were combined prior to fermentation, as well as some 1:1:1 blends of three different Spanish red grape musts. After blending the musts, co-fermentation was completed and the finished wines analyzed.

As you may have guessed already, co-fermentation resulted in wines that were more complex than if the wines were fermented separately. Co-fermented wines showed improvements in color characteristics, and significant increases in resveratrol content. Some of the blends resulted in increased antioxidant capacities, while other blends resulted in decreased antioxidant capacities. The authors claimed that these results suggest that co-fermentation or co-winemaking may be another technique winemakers could use to create diversity in their offerings for consumers, thus potentially giving them a market advantage that they wouldn’t otherwise have. My main beef with this study is

By Agne27 (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

that they did NOT compare the co-fermented blends with blends made after separate fermentations. The only comparisons were between the co-fermented blends and single varietals. I think the more appropriate comparison would be between the co-fermented blends and single fermentation blends blended together after fermentation, but maybe that’s just me.

Source: Gómez Gallego, M.A., Gómez García-Carpintero, E., Sánchez-Palomo, E., González Viñas, M.A., and Hermosín-Gutiérrez, I. 2012. Effect of co-winemaking in phenolic composition, color and antioxidant capacity of young red wines from La Mancha region. European Food Research and Technology 235: 155-167.

FORENSIC SCIENCE / TOXICOLOGY:

“A Fatal Case of CO2 Intoxication in a Fermentation Tank”. Stop reading this post now if you are at all upset by these types of topics (i.e. fatalities). I’m not going into gory details, but still, you all have imaginations and you should stop now if you’re a particularly sensitive individual….

This article, published in 2013, is a stark reminder of the sad reality that while winemaking can be fun and rewarding, it can be a dangerous job when care is not taken or proper training is not complete. While these tragic events are rare, they do happen and steps to avoid them should be taken by every winery.

What happened in this case was that there was a fermentation tank that had not been cleaned in 5 months, and until that time had been completely sealed, allowing CO2 to build up. An “unskilled worker” then entered the tank to clean it and quickly passed out due to too much CO2 and not enough oxygen. A second worker then went into the tank to rescue the first worker, but due to the incredibly high CO2 content inside the tank, the second worker quickly lost consciousness as well. Other staff members then found the two unconscious inside the tank and were able to easily pull out the first worker. As a result of the position of the second worker, the tank had to be rotated in order to get him out. CPR attempts were successful only for the first worker, which the second worker succumbed to his injuries and passed away. After autopsy, the cause of death was recorded as “CO2 intoxication/asphyxia in a vitiated atmosphere due to fermentation of wine mash”.

The take-home for this tragedy is to be sure to clean your tanks as soon as possible after cleaning, to avoid massive build-up of potentially deadly CO2 or other chemicals. If this is not done and one finds oneself presented with a sealed dirty tank that’s been sitting for some time, open it up and air it out for a long time before even attempting to clean it. Wearing oxygen masks/tanks wouldn’t be a bad idea either. Finally, please be sure to train all workers to understand this and all the possible dangers in the cellar (or vineyard) so that you don’t find yourselves in a similar tragic situation.

Source: Kettner, M.D, M., Ramsthaler, M.D, F., Juhnke, C., Dipl.Ing, Bux, M.D, R., and Schmidt, M.D, P. 2013. A Fatal Case of CO2 Intoxication in a Fermentation Tank. Journal of Forensic Sciences. doi: 10.1111/1556-4029.12058.

Posted in Literature Review Lightning Round

Tagged carbon dioxide, enology, forensic science, toxicology, viticulture, wine literature review lightning round, winemaking