83 research outputs found
Two decades of "Horse sweat" taint and Brettanomyces yeasts in wine: where do we stand now ?
ReviewThe unwanted modification of wine sensory attributes by yeasts of the species
Brettanomyces bruxellensis due to the production of volatile phenols is presently the main
microbiological threat to red wine quality. The effects of ethylphenols and other metabolites on
wine flavor is now recognized worldwide and the object of lively debate. The focus of this review
is to provide an update of the present knowledge and practice on the prevention of this problem
in the wine industry. Brettanomyces bruxellensis, or its teleomorph, Dekkera bruxellensis, are rarely
found in the natural environment and, although frequently isolated from fermenting substrates, their
numbers are relatively low when compared with other fermenting species. Despite this rarity, they
have long been studied for their unusual metabolical features (e.g., the Custers effect). Rising interest
over the last decades is mostly due to volatile phenol production affecting high quality red wines
worldwide. The challenges have been dealt with together by researchers and winemakers in an
effective way and this has enabled a state where, presently, knowledge and prevention of the problem
at the winery level is readily accessible. Today, the main issues have shifted from technological to
sensory science concerning the effects of metabolites other than ethylphenols and the over estimation
of the detrimental impact by ethylphenols on flavor. Hopefully, these questions will continue to be
tackled together by science and industry for the benefit of wine enjoymentinfo:eu-repo/semantics/publishedVersio
Beverage sensory modification
EditorialThe Special Issue on “Beverage Sensory Modification” gathers a series of articles that feature
the broad sense of sensory modification, either by improving flavor, taste, and mouthfeel properties
or by preventing their spoilage. The scope goes further than the usual technological measures that
modulate sensory properties and includes the psychological and cross-modal influences, where the
sensory modification is on the subject’s brain and not on the object’s physical-chemical propertiesinfo:eu-repo/semantics/publishedVersio
The 2016 Wines of Portugal Challenge: general implications of more than 8400 wine-score observations
The Wines of Portugal Challenge is an annual competition among
wines produced by over 1000 vintners in over 30 of the country’s
wine growing regions. In 2016, judges assigned scores to over
1300 wines resulting in over 8400 wine-score observations.
Analysis of that large sample yields implications about wine
judges’ ratings that are difficult to detect with statistical
significance in the small samples that are typical of most wine
tastings. The Challenge’s frequency distribution of scores showed
left skewness and local peaks just below the score thresholds for
bronze, silver and gold awards. Student’s t-tests showed that
there were no significant differences in scores assigned by
gender-of-judge, nationality-of-judge and to wines from different
regions. However, judges did assign higher scores to sweet wines
than to other types of wine. While the dispersion in scores was
material, p-values showed that the aggregate order of rating was
very unlikely to be random and the distributions of mean scores
showed that the strengths of judges’ preferences against the
least-preferred wines were stronger than those in favor of the
most-preferred wines. Ties between wines’ mean scores were
common and could be broken by several methods including the
preference probabilities implied by a Plackett-Luce modelinfo:eu-repo/semantics/publishedVersio
The Rise of Wine among Ancient Civilizations across the Mediterranean Basin
ReviewThe purpose of this work is to present the archaeological and historical background
of viticulture and winemaking from ancient times to the present day in the Mediterranean basin.
According to recent archaeological, archaeochemical and archaeobotanical data, winemaking emerged
during the Neolithic period (c. 7th–6th millennium BC) in the South Caucasus, situated between the
basins of the Black and Caspian Seas, and subsequently reached the Iberian Peninsula andWestern
Europe during the local beginning of Iron Age (c. 8th century BC), following the main maritime
civilizations. This review summarises the most relevant findings evidencing that the expansion
of wine production, besides depending on adequate pedo-climatic conditions and wine-growing
practices, also required the availability of pottery vessels to properly ferment, store and transport
wine without deterioration. The domestication of wild grapevines enabled the selection of more
productive varieties, further sustaining the development of wine trade. Other fermented beverages
such as mead and beer gradually lost their relevance and soon wine became the most valorised.
Together with grapes, it became an object and a system of value for religious rituals and social
celebrations throughout successive ancient Western civilizations. Moreover, wine was used for
medicinal purposes and linked to a wide variety of health benefits. In everyday life, wine was
a pleasant drink consumed by the elite classes and commoner populations during jubilee years,
festivals, and banquets, fulfilling the social function of easy communication. In the present work,
emphasis is put on the technical interpretation of the selected archaeological and historical sources
that may explain present viticultural and oenological practices. Hopefully, this review will contribute
to nurturing mutual understanding between archaeologists and wine professionalsinfo:eu-repo/semantics/publishedVersio
Historical and Heritage Sustainability for the Revival of Ancient Wine-Making Techniques and Wine Styles
ReviewThe purpose of this review is to provide a general description of ancient winemaking
techniques and wine styles that were most lauded in antiquity, in support of their revival and
dissemination today. From the first fully excavated winery, dating from the late fifth to the early
fourth millennium BC, the gentle crushing of grapes by foot and the probable absence of maceration
indicate that most wines were made with the aim of reducing astringency. The oxidative nature of
winemaking would have resulted in rapid browning, so that wines made from red grapes would have
had a similar color to those made from white grapes after being aged in clay vats for several years.
The difficulty in preventing the wine surface contact with the air would have resulted in biological
ageing under the yeast pellicle being a common occurrence. This phenomenon was not considered
a flaw, but a characteristic feature of highly prized wines. Dried grapes were used to make sweet
wines, which were also highly prized, therefore justifying the construction of dedicated facilities.
The addition of boiled juices, salt, resins, mixtures of herbs, spices, fruit juices, flowers, or honey to
the wines would have increased their taste pleasantness while improving their preservability and
medicinal properties. Indeed, today’s preference for flavored wines with a soft mouthfeel seems
to have been representative of the ancient elite consumers. Overall, the technical interpretation of
winemaking described in this review will provide solid historical support for the current rebirth of
ancient production methods, particularly those using pottery vesselsinfo:eu-repo/semantics/publishedVersio
Changes in sour rotten grape berry microbiota during ripening and wine fermentation
Available at ScienceDirectThis study investigated the microbiota of sour rotten wine grapes and its impact on wine fermentations.
Yeasts, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) were enumerated and identified on sound
and sour rot grapes during the ripening stage. The alteration of the ecological balance induced by sour rot
was particularly evidenced by the unequivocal increase of yeast and AAB counts on rotten grapes, since the
beginning of ripening. Yeast and AAB species diversity in rotten grape samples were much higher than
those found in sound grapes. LAB populations were low detected from both healthy and sour rotten grapes.
The yeast species Issatchenkia occidentalis, Zygoascus hellenicus and Zygosaccharomyces bailii and the AAB
species Gluconacetobacter hansenii, Gluconacetobacter intermedius and Acetobacter malorum, were recovered
from damaged grapes and resulting grape juices in the winery. Acetobacter orleaniensis and Acetobacter
syzygii were only recovered from sour rotten grapes.
Dekkera bruxellensis and Oenococcus oeni were only recovered after wine fermentation induced by starter inoculation,
irrespective of grape health, probably originating from cellar environment. After malolactic fermentation,
racking and sulphur dioxide addition the only remaining species were the yeast Trigonopsis
cantarellii and Saccharomyces cerevisiae, independently of the grape health statu
Caracterização das percepções sensoriais em vinhos brancos adicionados de diferentes moléculas com influência no aroma, sabor e sensações de boca
The present work was aimed at understanding the sensory responses induced by dry white wine modified with increasing concentrations of
different sensory active molecules. The tasting panel was composed by 34 trained subjects characterized according to gender, smoking
habits, 6-n-propylthiouracil (PROP) taster status, and sensitivity to tartaric acid, tannic acid and sucrose. Additional taste/mouthfeel
responsiveness was evaluated in a basal white wine added of tartaric acid, tannic acid and sucrose. The addition of a fruity odorant mixture
to the base white wine enabled the assessment of orthonasal aroma and taste intensities (sweetness, sourness, saltiness). The diversity of
taste/mouthfeel responsiveness in water or wine enabled to group individuals as high or low sensitives. Likewise, the tasting panel showed
two groups responding differently to aroma and flavor. Both high and low aroma sensitivity individuals showed equal (p>0.05) and
congruent response to in-mouth sweet flavor perception. Moreover, the high smell sensitive group was less sensitive to sourness and
saltiness than the low smell sensitives for the spiked wines across all flavor concentrations. Differences in PROP taster status and sensitivity
to other tastants in water solutions were not correlated with the taste/mouthfeel perceptions in wine. The individuals most sensitive to
sucrose in wine taste showed higher response to the fruity aroma. In conclusion, taste, mouthfeel and flavor perceptions showed a high
variability among individuals evidencing the advantage of grouping tasters with different chemosensory sensitivities to understand
cross-modal sensory interactionsO presente trabalho teve como objetivo compreender as respostas sensoriais induzidas por vinho branco seco modificado com
concentrações crescentes de diferentes moléculas com efeito no aroma. O painel de prova foi composto por 34 sujeitos treinados
caracterizados por sexo, hábitos de tabagismo, resposta ao 6-n-propiltiouracil (PROP), sensibilidade ao ácido tartárico, ácido tânico e Ă
sacarose. As perceções associadas ao ácido tartárico, ácido tânico e à sacarose foram também avaliadas em vinho branco. A adição de uma
mistura de aromas frutados ao vinho branco base possibilitou a avaliação da intensidade de aroma ortonasal e da intensidade de sabor em
relação à perceção da doçura, acidez e salgado. A diversidade de respostas aos sabores e à sensação de boca, em água e em vinho, permitiu
separar os indivĂduos em dois grupos com sensibilidade alta e baixa. Em conjunto, os provadores responderam de forma diferente ao aroma
e ao sabor do vinho adicionado da mistura de compostos de aroma. Tanto indivĂduos de alta como de baixa sensibilidade ao aroma ortonasal
apresentaram uma resposta igual (p>0.05) e congruente com a percepção de doçura na boca. AlĂ©m disso, o grupo mais sensĂvel ao cheiro era
menos sensĂvel aos sabores ácido e salgado do que os menos sensĂveis ao cheiro, para os vinhos adicionados de todas as concentrações de
aroma. As diferenças na resposta ao PROP e sensibilidades ao ácido tartárico, ácido tânico e à sacarose, em soluções aquosas, não foram
correlacionadas com as perceções respetivas em vinho. No entanto, os indivĂduos mais sensĂveis Ă sacarose no vinho apresentaram maior
resposta ao aroma frutado. Em conclusĂŁo, as perceções de sabor e sensação de boca mostraram elevada variabilidade entre os indivĂduos.
Desta forma, é vantajoso o agrupamento de provadores em função da sua sensibilidade quimo-sensorial para entender as interações
multimodais entre os sentidos do olfato, gosto e tato, durante a prova de vinhosinfo:eu-repo/semantics/publishedVersio
The microbial ecology of wine grapes
Available at ScienceDirectGrapes have a complex microbial ecology including filamentous fungi, yeasts and bacteria with different
physiological characteristics and effects upon wine production. Some species are only found in grapes,
such as parasitic fungi and environmental bacteria, while others have the ability to survive and grow in
wines, constituting the wine microbial consortium. This consortium covers yeast species, lactic acid bacteria
and acetic acid bacteria. The proportion of these microorganisms depends on the grape ripening stage and on
the availability of nutrients. Grape berries are susceptible to fungal parasites until véraison after which the
microbiota of truly intact berries is similar to that of plant leaves, which is dominated by basidiomycetous
yeasts (e.g. Cryptococcus spp., Rhodotorula spp. Sporobolomyces spp.) and the yeast-like fungus Aureobasidium
pullulans. The cuticle of visually intact berries may bear microfissures and softens with ripening, increasing
nutrient availability and explaining the possible dominance by the oxidative or weakly fermentative ascomycetous
populations (e.g. Candida spp., Hanseniaspora spp., Metschnikowia spp., Pichia spp.) approaching harvest
time. When grape skin is clearly damaged, the availability of high sugar concentrations on the berry
surface favours the increase of ascomycetes with higher fermentative activity like Pichia spp. and Zygoascus
hellenicus, including dangerous wine spoilage yeasts (e.g. Zygosaccharomyces spp., Torulaspora spp.), and of
acetic acid bacteria (e.g. Gluconobacter spp., Acetobacter spp.). The sugar fermenting species Saccharomyces
cerevisiae is rarely found on unblemished berries, being favoured by grape damage. Lactic acid bacteria are
minor partners of grape microbiota and while being the typical agent of malolactic fermentation, Oenococcus
oeni has been seldom isolated from grapes in the vineyard. Environmental ubiquitous bacteria of the genus
Enterobacter spp., Enterococcus spp., Bacillus spp., Burkholderia spp., Serratia spp., Staphylococcus spp.,
among others, have been isolated from grapes but do not have the ability to grow in wines. Saprophytic
moulds, like Botrytis cinerea, causing grey rot, or Aspergillus spp., possibly producing ochratoxin, are only active
in the vineyard, although their metabolites may affect wine quality during grape processing.
The impact of damaged grapes in yeast ecology has been underestimated mostly because of inaccurate grape
sampling. Injured berries hidden in apparently sound bunches explain the recovery of a higher number of
species when whole bunches are picked. Grape health status is the main factor affecting the microbial ecology
of grapes, increasing both microbial numbers and species diversity. Therefore, the influence of abiotic
(e.g. climate, rain, hail), biotic (e.g. insects, birds, phytopathogenic and saprophytic moulds) and viticultural
(e.g. fungicides) factors is dependent on their primary damaging effect
Effect of ethanol, sulfur dioxide and glucose on the growth of wine spoilage teasts using response surface methodology
Research ArticleResponse surface methodology (RSM) was used to study the effect of three factors, sulfur
dioxide, ethanol and glucose, on the growth of wine spoilage yeast species, Zygosaccharomyces
bailii, Schizosaccharomyces pombe, Saccharomycodes ludwigii and Saccharomyces
cerevisiae. Seventeen central composite rotatable design (CCRD) trials were designed
for each test yeast using realistic concentrations of the factors (variables) in premium red
wine. Polynomial regression equations were fitted to experimental data points, and the
growth inhibitory conditions of these three variables were determined. The overall results
showed Sa. ludwigii as the most resistant species growing under high ethanol/free sulfur dioxide
concentrations, i.e., 15% (v/v)/20 mg L-1, 14% (v/v)/32 mg L-1 and 12.5% (v/v)/40 mg
L-1, whereas other yeasts did not survive under the same levels of ethanol/free sulfur dioxide
concentrations. The inhibitory effect of ethanol was primarily observed during longer incubation
periods, compared with sulfur dioxide, which showed an immediate effect. In some
CCRD trials, Sa. ludwigii and S. cerevisiae showed growth recovery after a short death period
under the exposure of 20–32 mg L-1 sulfur dioxide in the presence of 11% (v/v) or more
ethanol. However, Sc. pombe and Z. bailii did not show such growth recovery under similar
conditions. Up to 10 g L-1 of glucose did not prevent cell death under the sulfur dioxide or
ethanol stress. This observation demonstrates that the sugar levels commonly used in wine
to sweeten the mouthfeel do not increase wine susceptibility to spoilage yeasts, contrary to
the anecdotal evidenceinfo:eu-repo/semantics/publishedVersio
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