LACHANCEA THERMOTOLERANS, THE NON-SACCHAROMYCES YEAST THAT REDUCES THE VOLATILE ACIDITY OF WINES

Alice Vilela - 04 Aug 2018

To improve the quality of fermented drinks, or more specifically, wine, some strains of yeast have been isolated, tested and studied, such as Saccharomyces and non-Saccharomyces. Some non-conventional yeasts present good fermentative capacities and are able to ferment in quite undesirable conditions, such as the case of must, or wines that have a high concentration of acetic acid. One of those yeasts is Lachancea thermotolerants (L. thermotolerans), which has been studied for its use in wine due to its ability to decrease pH through L-lactic acid production, giving the wines a pleasant acidity. This review focuses on the recent discovery of an interesting feature of L. thermotolerans—namely, its ability to decrease wines’ volatile acidity.

Image: Shutterstock

EFFECTS OF THE TIMING OF CLUSTER THINNING ON PINOT NOIR GRAPES AND WINES

Paul F. W. Mawdsley, Jean Catherine Dodson Peterson and L. Federico Casassa - 04 Aug 2018

A two-year study was performed to evaluate the effects of the timing of cluster thinning on Pinot noir grapes and wines in the central coast of California. Vines were thinned to one cluster per shoot at three selected time-points during the growing season, and fruit was harvested and made into wine. No consistent effect of cluster thinning was found in wine phenolic profile or color across a cool (2016) and a warm (2017) growing season. The growing season had a more significant effect than the cluster thinning treatment for most parameters measured. There was no detectable overall sensory difference between the non-thinned control wines and any of the thinned treatment wines. Based on current results, Pinot noir vineyards on the central coast of California can support crop loads that result in Ravaz Index values from 3 to 6 without concern for impacting ripening potential or negatively affecting fruit composition.

Image: Wikipedia

ENZYMES FOR WINE FERMENTATION: CURRENT AND PERSPECTIVE APPLICATIONS

Harald Claus and Kiro Mojsov - 04 Aug 2018

Enzymes are used in modern wine technology for various biotransformation reactions from prefermentation through fermentation, post-fermentation and wine aging. Industrial enzymes offer quantitative benefits (increased juice yields), qualitative benefits (improved color extraction and flavor enhancement) and processing advantages (shorter maceration, settling and filtration time). This study gives an overview about key enzymes used in winemaking and the effects of commercial enzyme preparations on process engineering and the quality of the final product. In addition, we highlight on the presence and perspectives of beneficial enzymes in wine-related yeasts and lactic acid bacteria.

Image: Shutterstock

NOVEL WINE YEAST FOR IMPROVED UTILISATION OF PROLINE DURING FERMENTATION

Danfeng Long, Kerry L. Wilkinson, Dennis K. Taylor and Vladimir Jiranek - 04 Aug 2018

Proline is the predominant amino acid in grape juice, but it is poorly assimilated by wine yeast under the anaerobic conditions typical of most fermentations. Exploiting the abundance of this naturally occurring nitrogen source to overcome the need for nitrogen supplementation and/or the risk of stuck or sluggish fermentations would be most beneficial. This study describes the isolation and evaluation of a novel wine yeast isolate, Q7, obtained through ethyl methanesulfonate (EMS) mutagenesis. The utilisation of proline by the EMS isolate was markedly higher than by the QA23 wild type strain, with approximately 700 and 300 mg/L more consumed under aerobic and self-anaerobic fermentation conditions, respectively, in the presence of preferred nitrogen sources. 

Image: Shutterstock

DRONES SHOWING THEIR VALUE IN VINEYARDS

Wine Australia - 15 Jun 2018

The idea of using drones to provide accurate, immediate and cost-effective snapshots of the micro-climate anywhere in or above vineyards is a step closer to reality. Basically, if you equip an unmanned air vehicle (UAV) with a normal camera and a long-range infrared camera set up to work as a temperature sensor you can measure the temperature of vines, grapes, buds and the ground itself.

Researchers identify the dried and cooked fruit aroma in Merlot and Cabernet Sauvignon

Karien O'Kennedy - 17 May 2018

French researchers identified C10-massoia lactone as the dried fig character in Merlot and Cabernet Sauvignon. This aroma occur due to longer hang-time on the vine as a result of warmer climates. Researchers compared Merlot and Cabernet Sauvignon musts and wines with and without dried fruit aromas via GC-O-MS. Various odorous zones were obtained and one in particular was found in wines described having prune and fig flavours. The wine volatile fractions were also analysed via GC-O-MS with a corresponding reference compound, hence the dried fig character was identified as C10-massoia lactone.

Sensory and chemical drivers of wine minerality aroma

Karien O'Kennedy - 17 May 2018

Researchers studied wines from grapes from the two sides of the Serein river in Chablis. Wines from the left side of the river scored higher in minerality than wines from the right side. These wines also had higher levels of methanethiol (MeSH, a negative sulphur compound) that have a masking effect on fruity and floral characteristics. The wines from the right bank had higher concentrations of norisoprenoids, responsible for fruity and floral characteristics. It also had higher copper concentrations, which could be the factor responsible for lower MeSH.

Discovery shows wine grapes gasping for breath

Infowine - 17 May 2018

University of Adelaide researchers have discovered how grapes “breathe”, and that shortage of oxygen leads to cell death in the grape. The discovery raises many questions about the potentially significant impacts on grape and wine quality and flavour and vine management, and may lead to new ways of selecting varieties for warming climates.

A new twist on the fights against fungus

Wine Australia - 02 Apr 2018

Finding a way to fight fungus without fungicides is a long game, but CSIRO researchers in Adelaide are making significant progress.

Image: Richard Hamilton, Hamilton Viticulture

Synthetic genome engineering forging new frontiers for wine yeast

Sakkie Pretorius - 30 Jan 2018

A large international project – the Synthetic Yeast Genome Project – is now underway to synthesize all 16 chromosomes of a laboratory wine yeast strain by 2018. If successful, S. cerevisiae will become the first eukaryote to cross the horizon of in silico design of complex cells through de novo synthesis, reshuffling, and editing of genomes. Therefore, this article seeks to help prepare the wine industry – an industry rich in history and tradition on the one hand, and innovation on the other – for the inevitable intersection of the ancient art practiced by winemakers and the inventive science of pioneering “synthetic genomicists”.

An overview of the biodynamic wine sector

Karien O'Kennedy - 30 Jan 2018

Using a systematic literature review, this review aims to investigate the biodynamic production system in the viticulture and winemaking process. In particular, the review examines, 1) the biodynamic practice and its main characteristics including the certification system; 2) the biodynamic market characteristics and the recent trends, the production costs and the marketing strategies adopted by wineries; 3) the demand attributes and wine consumers’ perception on sustainable practices and “green products” such as biodynamic products; and 4) the association between the biodynamic wine chain and the environment.

A little microbiology goes a long way

Wine Australia - 10 Apr 2017

A three-year Wine Australia research project provides a much clearer picture of the diverse microbial populations that exist in treatment plants.

Can Lasers Help to Deter Birds From Damaging Vineyards?

Lauren Waldhuter - 05 Apr 2017

Wineries and grape growers have a range of strategies for keeping keep birds at bay, from shooting them and hanging up shiny streamers to firing off gas guns to spook them.

Image: Lauren Waldhuter

What actually happens when you add water to must?

Wine Australia - 27 Mar 2017

Food Standards Australia and New Zealand (FSANZ) recently announced a decision to allow the limited addition of water to high sugar musts and juice to reduce the chance of problems arising during fermentation.

Study Finds Red Wine Compound Slows Aging in Muscles and Neurons

Samantha Falewée - 27 Mar 2017

A study, led by researchers at the Virginia Tech Carilion School of Medicine and Research Institute, has found evidence that resveratrol can protect neural connections in the brain and muscle fibers from the adverse effects of ageing.

Can Vitis vinifera canes be a source of natural fungicides?

Tristan Richard, Assia Abdelli-Belhad, Xavier Vitrac, Pierre Waffo-Téguo, Jean-Michel Mérillon - 06 Mar 2017

This study investigated the use of Vitis vinifera canes as a source of natural funigicides against downy mildew.

The results indicated that stilbenes from grapevine canes are good candidates as natural fungicides against downy mildew. Given the very large quantity of grape canes available each year, this strategy could be scaled up to control this grapevine disease in a sustainable manner. Further research is still needed.

Image: Shutterstock

Mealybugs and under vine management

Tessa Nicholson - 06 Mar 2017

This new research programme (funded by New Zealand Winegrowers) aims to identify new tactics that might slow or even prevent the spread of leafroll virus by defining the relationship between the vine, the ground cover plants and mealybugs.

Expectation or sensorial reality? An empirical investigation of the biodynamic calendar for wine drinkers

Wendy V. Parr, Dominique Valentin, Phil Reedman, Claire Grose and James A. Green - 28 Feb 2017

Researchers have found that the taste of wine is not affected by the cycles of the moon as claimed by the biodynamic philosophy. 

Australia Invests $5.3 m in R&D; projects on Shiraz Terroir

Rachel Arthur - 27 Jan 2017

Wine Australia has today announced a six year, $5.3m AUD ($4m USD) R&D investment that will look at Australia’s unique terroirs and how they influence wine style and quality. 

New nontoxic hydrogels could aid in wine production and other applications

Infowine - 10 Jan 2017

New nontoxic hydrogels developed by Stanford engineers could aid in food production and other applications.

University of Arkansas Debuts New Winegrape Varieties

Christina Herrick - 10 Jan 2017

Twenty years in the making, the University of Arkansas has released two new winegrapes that can withstand heat, humidity, rain and icy winters – ‘Opportunity’ and ‘Enchantment.’

Image: Fred Miller

Virtual vineyard gate aims to keep grape pests out

Andrew Spence - 10 Jan 2017

Software initially developed to safeguard the Canadian poultry industry is being trialled by Australian wineries to help keep pests and diseases out of premium vineyards. It is still early days for the project

The vineyard cyber monitoring system known as Project Boundary Rider uses an app that places a virtual fence around vineyards, tracking the movements of people across boundaries via GPS on a smartphone. In the event of a pest or disease outbreak, the technology provides instant data to enable a rapid response to contain the spread and minimise loss.

Image: The Lead

Impacts of grapevine leafroll disease on fruit yield and grape and wine chemistry

Article review by Lucinda Heyns - 18 Nov 2016

Washington State University did a three year study from 2009 – 2011 to look at the impact of grapevine leafroll disease (GLD) on grapevine fruit yield as well as grape and wine chemistry. An own rooted, commercial Merlot vineyard, planted in 1998 in Yakima Valley (eastern Washington state) was used for the study. Vines showing symptoms and that tested positive for GLDaV-3 were compared to adjacent non-symptomatic vines that tested negative. Each year, the vines were retested to confirm their status. Grapes were harvested at different stages of berry development and juice analysis done regularly throughout ripening.

Study finds red wine can help to reduce inflammation

Georgia State University - 06 Oct 2016

A component of red wine and grapes can help control inflammation induced by a bacterial pathogen that is linked to upper respiratory tract inflammatory diseases such as asthma, chronic obstructive pulmonary diseases (COPD) and middle ear infection (otitis media), according to a study.

Image: Shutterstock

Can an electronic tongue predict taste perception?

Darren Smith - 06 Oct 2016

Researchers from the University of South Australia have developed an electronic device they claim can accurately determine the age and quality of a wine

French microalgae may be the answer to key vine diseases

Harpers.co.uk - 19 Sep 2016

A microalgae found in the sea off Brittany’s coastline can wipe-out key vine diseases with new scientific tests in France showing 100% efficiency in destroying Downey Mildew. The major scientific breakthrough could provide natural alternatives to the use of pesticides on vineyards.

Structural and functional MRI differences in master sommeliers

Sarah Banks et al. 2016 - 12 Sep 2016

The study assessed differences in Master Sommeliers’ brains, compared with controls, in structure and also in functional response to olfactory and visual judgment tasks. The results indicate that sommeliers’ brains show specialisation in the expected regions of the olfactory and memory networks, and also in regions important in integration of internal sensory stimuli and external cues.

Scientists find promise treating Alzheimer's with a mix of wine compounds

Christine Dalton in Wine Spectator - 18 Aug 2016

A team of researchers from Australia has found promising results treating Alzheimer's disease with resveratrol combined with two other wine compounds.

Grape vines exposed to smoke to test taint from wildfires

By Maegan Murray, WSU Tri-Cities - 18 Aug 2016

In a new study, Tom Collins, Washington State University Tri-Cities assistant professor of viticulture and enology, is exposing vines to smoke to better understand how the chemical composition of grapes changes. He wants to know how much smoke it takes to create smoke taint in wine grapes and wine, as well as how to lessen the problem.

Image copyright: Washington State University

Wine aroma is even more important than we thought

Wine Australia - 18 Aug 2016

Research at the AWRI suggests the long, lingering aftertaste that makes you want another sip – and maybe another glass – of a good wine may in fact be due to retro-nasal perception of aromas released from molecules called glycosides, which occur naturally in grapes. We’ve always known they are there, but until now have not fully understood their potential.

Researchers study colored shade nets on grapes

Ted Rieger in Wines and Vines - 14 Jul 2016

Oakville, Calif.—Researchers from the University of California, Davis, began a trial this year at the Oakville Experimental Station in Napa Valley to evaluate the use of different colors of commercially available shade netting and its effects on grape cluster temperature and light exposure in relation to chemical and phenolic development and composition in grape berries.

Read more at: http://www.winesandvines.com/template.cfm?section=news&content=171307
Copyright © Wines & Vines

Australia invests in research to safeguard wine grapes from smoke

Wine Australia - 06 Jul 2016

This project will examine practices and advanced technologies that may provide the Australian grape and wine community with innovative and cost-effective tools to minimise the unintended impacts of controlled burns and wildfires near wine regions.’

The new project aims to safeguard the supply of grapes and improve profitability for Australia’s grapegrowers. 

Image: Wine Australia

Development of an app that can assess berry ripeness and help with decision making in harvest

Wine Australia - 29 Jun 2016

A research project funded by Wine Australia is looking to develop a smartphone imaging tool to assess grapevine berry and bunch characteristics.
 
The aim is to make it easy for viticulturists to determine the optimum fruit picking ‘window’ to suit desired wine styles by tracking the evolution of the fruit’s colour (white varieties) or volume (for red and white varieties).
 
- Image: Shutterstock

Can science help to identify a wine's origin?

Wine Australia - 28 Jun 2016

A new project at the AWRI led by Research Scientist Dr Martin Day is looking to determine whether by combining the right mix of parameters it is possible to prove with sufficient certainty where a wine did – or in some cases didn’t – come from.

San Joaquin Valley investigates performance of alternative varietals to heat

Lindsay Jordan - 16 Jun 2016

Researchers evaluated the performance of alternative varieties to heat. By selecting grape varieties that can innately produce superior fruit in the heat of the SJV, some of the wine quality issues associated with warm climate wine production may be alleviated.

Impacts of grapevine leafroll disease on fruit yield and grape and wine chemistry

Article review by Lucinda Heyns - 29 May 2016

Washington State University did a three year study from 2009 – 2011 to look at the impact of grapevine leafroll disease (GLD) on grapevine fruit yield as well as grape and wine chemistry. An own rooted, commercial Merlot vineyard, planted in 1998 in Yakima Valley (eastern Washington state) was used for the study. Vines showing symptoms and that tested positive for GLDaV-3 were compared to adjacent non-symptomatic vines that tested negative. Each year, the vines were retested to confirm their status. Grapes were harvested at different stages of berry development and juice analysis done regularly throughout ripening.

Bulk wine not affected by transport choices

Wine Australia - 11 May 2016

Wine Australia funded a project with the AWRI looking at the bulk transport process, and whether the choices wine companies make have any sensory or chemical impact on the wine during or after transit. Researchers Simon Nordestgaard and Eric Wilkes together with wine sector collaborators tracked more than one million litres of wine bound for the UK over 15 months and the results were very positive.

Red Wine and Coffee Are Good for Your Guts, Study Finds

Christine Dalton in Wine Spectator - 11 May 2016

Researchers find red-wine drinkers have more diverse gut microbiomes, which means better health. So for now, keep drinking your red wine and coffee. Your gut will thank you.

 

 

EFFECT OF OXYGEN EXPOSURE DURING FERMENTATION ON VOLATILE SULFUR COMPOUNDS IN SHIRAZ

Bekker et al - 13 Apr 2016

Oxygen (O2) plays a fundamental role in the establishment of wine style and aroma. The effect of O2 treatment during fermentation on the formation of volatile sulfur compounds (VSCs) and the subsequent impact on the sensory profile of wine was investigated. Traditional VSC remediation strategies were also evaluated.

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