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1.
Sanitization of Oak Barrels for Wine-A Review.
Stadler, E, Fischer, U
Journal of agricultural and food chemistry. 2020;(19):5283-5295
Abstract
Oak barrels form an integral part of wine production, especially that of high-quality wines where they are implemented as fermentation and aging vessels. Insufficient cleaning and sanitization of barrels can result in microbial spoilage which may have a detrimental impact on wine quality. To date, no review has been published on the various sanitization methods for wine barrels. The objective of this review is to provide an overview of the sanitization methods used in wineries from conventional techniques like the use of sulfur dioxide and steam to alternative and new approaches using ozone and high-power ultrasound. The methods' efficacies are outlined in terms of their ability to eradicate spoilage microorganisms such as Brettanomyces and acetic or lactic acid bacteria. Furthermore, their advantages and drawbacks are described together with their influence on physicochemical properties of the wood. Finally, limitations in existing knowledge are discussed and areas that merit further research are identified.
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2.
Consumer perception and behaviour related to low-alcohol wine: do people overcompensate?
Bucher, T, Frey, E, Wilczynska, M, Deroover, K, Dohle, S
Public health nutrition. 2020;(11):1939-1947
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Abstract
OBJECTIVE Compared with standard wines, low-alcohol wines may have several social and health benefits. Innovative production processes have led to high-quality light wines. It is, however, unclear how consumers perceive and consume these alcohol-reduced wines. The current study aimed to investigate how people evaluate low-alcohol wine (Sauvignon Blanc) and if the reduction in alcohol and the information that a wine is low in alcohol influences consumption. DESIGN Randomised controlled trial (RCT). SETTING Participants were invited to a wine tasting and randomised into one of the three conditions: they either tasted a 'new white wine' (12·5 % alcohol content), a 'new low-alcohol white wine' (8·0 % alcohol content) or they tasted the low-alcohol wine but were not aware that the wine was reduced in alcohol (low-alcohol, blinded). PARTICIPANTS Ninety participants (42 % male, mean age = 41 (sd 14) years). RESULTS Mean comparisons showed similar ratings for the low-alcohol conditions and the standard alcohol condition (mean > 5·6/7). The mean consumed amount across all conditions did not differ (162 (sd 71) ml, (F2,86 = 0·43, P > 0·05)), hence people who tasted the low-alcohol wine consumed approximately 30 % less alcohol. However, participants were willing to pay more for the normal wine compared with the low-alcohol wine, (F2,87 = 3·14, P < 0·05). CONCLUSIONS Participants did not alter their drinking behaviour in response to the reduced alcohol content, and the low-alcohol wine was perceived positively. There might be an emerging market potential for wine of reduced alcohol content, but consumers may not be willing to pay the same price as for the standard wine.
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Assessing the Aflatoxins Mitigation Efficacy of Blueberry Pomace Biosorbent in Buffer, Gastrointestinal Fluids and Model Wine.
Rasheed, U, Ain, QU, Yaseen, M, Santra, S, Yao, X, Liu, B
Toxins. 2020;(7)
Abstract
Blueberry (BB) and cherry pomace were investigated as new biosorbents for aflatoxins (AFs) sequestration from buffered solutions, gastrointestinal fluids and model wine. Among the tested biosorbents, BB exhibited the maximum adsorption performance for AFs and hence was further selected for the optimization of experimental parameters like pH, dosage, time and initial concentration of AFs. Material characterizations via scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, N2 adsorption-desorption isothermal studies, thermogravimetric analysis (TGA) and X-ray photon spectroscopy (XPS) techniques revealed useful information about the texture and chemical composition of the biosorbents. The fitting of isothermal data with different models showed the model suitability trend as: Sips model > Langmuir model > Freundlich model, where the theoretical maximum adsorption capacity calculated from the Sips model was 4.6, 2.9, 2.7 and 2.4 mg/g for AFB1, AFB2, AFG1 and AFG2, respectively. Kinetics study revealed the fast AFs uptake by BB (50-90 min) while thermodynamics studies suggested the exothermic nature of the AFs adsorption from both, single as well as multi-toxin buffer systems, gastrointestinal fluids and model wine. Accrediting to the fast and efficient adsorption performance, green and facile fabrication approach and cost-effectiveness, the newly designed BB pomace can be counted as a promising contender for the sequestration of AFs and other organic pollutants.
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Is it scientifically justifiable to exclude wine and/or unfermented grape derivatives from the diet of consumers with or at risk of developing type-2 diabetes?
Restani, P, Di Lorenzo, C, Fradera, U, Stockley, CS, Teissedre, PL, Ruf, JC, Iasiello, B, Biella, S, Colombo, F, Kosti, RI
Food & function. 2020;(12):10266-10278
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Abstract
The abuse of alcoholic beverages has been associated with an increased risk of chronic-degenerative diseases, including diabetes mellitus, so that there is a general diffidence towards the low/moderate consumption of wine by individuals with type-2 diabetes (T2D) or at risk of developing it. This narrative review investigates by critical revision of the scientific literature whether wine/grape derivatives must be excluded or if their low/moderate consumption could be part of the daily diet of T2D individuals. Although further intervention studies on the consumption of alcoholic beverages and the development or control of T2D are needed, the burden of evidence suggests that low/moderate wine consumption could have beneficial effects.
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5.
Processes and purposes of extraction of grape components during winemaking: current state and perspectives.
Unterkofler, J, Muhlack, RA, Jeffery, DW
Applied microbiology and biotechnology. 2020;(11):4737-4755
Abstract
The quality of red wine is dependent on the presence not only of volatile compounds that influence wine aroma but also on phenolic compounds due to their impact on mouthfeel, colour, flavour and ageing potential. Whereas wine aroma arises from the grapes, action of microorganisms and maturation phenomena, red wine phenolics are predominantly found in the grape berry skins and seeds and are extracted during maceration into the fermenting must (i.e. grape solids and juice). Thus, although every step in winemaking has a significant impact on the outcome of the finished product, it can be considered that fermentation and the ensuing extraction of grape components are the most critical value adding step in the process. This mini-review examines such aspects, and against this backdrop, considers the need for improvements to fermentation control during wine production, to optimise the outcome of extraction from grape solids. Specifically, there is interest in modulating and forecasting wine composition based on grape specifications, and with this, the ability to regulate winery production practices to achieve target quality specifications. Such predictions and measures are proposed to help winemakers adapt to emerging issues associated with climate change. KEY POINTS • Definition and description of important grape metabolites extracted during winemaking. • Description of processes influencing development and extraction of grape components. • Includes key aspects related to vineyard, harvesting, winemaking, and ageing. • Covers future trends regarding extrac Mini-Reviewtion, climate change and production efficiency.
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Single-nucleotide polymorphism (SNP) genotyping assays for the varietal authentication of 'Nebbiolo' musts and wines.
Boccacci, P, Chitarra, W, Schneider, A, Rolle, L, Gambino, G
Food chemistry. 2020;:126100
Abstract
'Nebbiolo' (Vitis vinifera L.) is renowned for its use in producing monovarietal high-quality red wines, such Barolo and Barbaresco. The fight against fraud to safeguard high-quality productions requires an effective varietal identification system applicable in musts and wines. 'Nebbiolo'-specific single-nucleotide polymorphisms (SNPs) were identified starting from available databases and 260 genotypes analysed by Vitis18kSNP array. Two SNPs were sufficient to identify 'Nebbiolo' from 1157 genotypes. The SNP TaqMan® genotyping assays developed in this work successfully identified 'Nebbiolo' in all musts and wines collected at different experimental wine-making steps. The high sensitivity of the assays allowed identification of must mixtures at 1% and wine mixtures at 10-20% with non-'Nebbiolo' genotypes. In commercial wines, the amplification efficiency was limited by the low amount of grapevine DNA and the presence of PCR inhibitors. The TaqMan® genotyping assay is a rapid, highly sensitive and specific methodology with remarkable potential for varietal identification in wines.
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Tasting the terroir of wine yeast innovation.
Pretorius, IS
FEMS yeast research. 2020;(1)
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Abstract
Wine is an archetypal traditional fermented beverage with strong territorial and socio-cultural connotations. Its 7000 year history is patterned by a tradition of innovation. Every value-adding innovation - whether in the vineyard, winery, supply chain or marketplace - that led to the invention of a new tradition spurred progress and created a brighter future from past developments. In a way, wine traditions can be defined as remembered innovations from the distant past - inherited knowledge and wisdom that withstood the test of time. Therefore, it should not be assumed a priori that tradition and innovation are polar opposites. The relations between the forces driven by the anchors of tradition and the wings of innovation do not necessarily involve displacement, conflict or exclusiveness. Innovation can strengthen wine tradition, and the reinvention of a tradition-bound practice, approach or concept can foster innovation. In cases where a paradigm-shifting innovation disrupts a tradition, the process of such an innovation transitioning into a radically new tradition can become protracted while proponents of divergent opinions duke it out. Sometimes these conflicting opinions are based on fact, and sometimes not. The imperfections of such a debate between the 'ancients' and the 'moderns' can, from time to time, obscure the line between myth and reality. Therefore, finding the right balance between traditions worth keeping and innovations worth implementing can be complex. The intent here is to harness the creative tension between science fiction and science fact when innovation's first-principles challenge the status quo by re-examining the foundational principles about a core traditional concept, such as terroir. Poignant questions are raised about the importance of the terroir (biogeography) of yeasts and the value of the microbiome of grapes to wine quality. This article imagines a metaphorical terroir free from cognitive biases where diverse perspectives can converge to uncork the effervescent power of territorial yeast populations as well as 'nomadic' yeast starter cultures. At the same time, this paper also engages in mental time-travel. A future scenario is imagined, explored, tested and debated where terroir-less yeast avatars are equipped with designer genomes to safely and consistently produce, individually or in combination with region-specific wild yeasts and or other starter cultures, high-quality wine according to the preferences of consumers in a range of markets. The purpose of this review is to look beyond the horizon and to synthesize a link between what we know now and what could be. This article informs readers where to look without suggesting what they must see as a way forward. In the context of one of the world's oldest fermentation industries - steeped in a rich history of tradition and innovation - the mantra here is: respect the past, lead the present and secure the future of wine.
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Grapevine as a Rich Source of Polyphenolic Compounds.
Šikuten, I, Štambuk, P, Andabaka, Ž, Tomaz, I, Marković, Z, Stupić, D, Maletić, E, Kontić, JK, Preiner, D
Molecules (Basel, Switzerland). 2020;(23)
Abstract
Grapes are rich in primary and secondary metabolites. Among the secondary metabolites, polyphenolic compounds are the most abundant in grape berries. Besides their important impacts on grape and wine quality, this class of compounds has beneficial effects on human health. Due to their antioxidant activity, polyphenols and phenolic acids can act as anti-inflammatory and anticancerogenic agents, and can modulate the immune system. In grape berries, polyphenols and phenolic acids can be located in the pericarp and seeds, but distribution differs considerably among these tissues. Although some classes of polyphenols and phenolic acids are under strict genetic control, the final content is highly influenced by environmental factors, such as climate, soil, vineyard, and management. This review aims to present the main classes of polyphenolic compounds and phenolic acids in different berry tissues and grape varieties and special emphasis on their beneficial effect on human health.
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A quarter century of wine pigment discovery.
Waterhouse, AL, Zhu, J
Journal of the science of food and agriculture. 2020;(14):5093-5101
Abstract
The red grape berry pigments, anthocyanins, were characterized in the early 20th century, but investigations of wine pigments were stymied during that era. The question of their identity was a major challenge for wine chemists. A number of techniques showed that the pigments were polymeric in nature. Some structures were postulated by mid-century based on reactions between anthocyanins and condensed tannin, and later postulated wine pigments were observed in model reactions. Some related compounds were then observed in wine. By the end of the 20th century, the ionization of non-volatiles for mass spectrometry opened the door to these compounds. In addition, a new class of compounds was observed, the pyranoanthocyanins, a product of fermentation and aging metabolites with anthocyanins. These compounds possess the pigment stability to SO2 and pH change that is characteristic of aged red wine. Aging experiments show a dynamic situation with shifts in the population of pigment classes over time. The very large number of diverse pigments explains why it has been so difficult to answer the century-old question of the structure of wine pigments. Our current understanding is founded on the use of mass spectral analysis using electrospray and related ionization techniques over the last 25 years. Future progress will rely on more sophisticated analysis of this very complex mixture of substances. © 2019 Society of Chemical Industry.
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Increased glycosidase activities improved the production of wine varietal odorants in mixed fermentation of P. fermentans and high antagonistic S. cerevisiae.
Li, N, Wang, QQ, Xu, YH, Li, AH, Tao, YS
Food chemistry. 2020;:127426
Abstract
A selected Pichia fermentans strain was simultaneously and sequentially inoculated in synthetic and real juice with S. cerevisiae strains of different antagonistic activities in a ratio 1:1 to observe the correlation between varietal odorants and glycosidase activities. Fermentations using pure S. cerevisiae strains were used for comparison. Yeast biomass and glycosidase activities were monitored, varietal odorants were detected using HS-SPME-GC/MS during fermentation. The final wine aroma attributes were analyzed by trained panelists. Results showed that co-inoculation with high antagonistic S. cerevisiae resulted in higher glycosidase activities than others. Pearson correlation analysis indicated that yeast biomass was positively related to glycosidase activities during fermentation. The increase in glycosidase activities was the main reason for the higher production of terpenes and C13-norisoprenoids, and for the lower C6 compound content, which lead to superior fruity and floral aromas in the final wine samples of the high antagonistic S. cerevisiae group.