From Sugar of Grape to Alcohol of Wine: Sensorial Impact of Alcohol in Wine

Abstract

The quality of grapes, as well as wine quality, flavor, stability, and sensorial characteristics depends on the content and composition of several different groups of compounds from grapes. One of these groups of compounds are sugars and consequently the alcohol content quantified in wines after alcoholic fermentation. During grape berry ripening, sucrose transported from the leaves is accumulated in the berry vacuoles as glucose and fructose. The wine alcohol content continues to be a challenge in oenology, as it is also the study of the role of chemosensory factors in alcohol intake and consumer preferences. Several technical and scientific advances have occurred in recent years, such as identification of receptors and other important molecules involved in the transduction mechanisms of flavor. In addition, consumers know that wines with high alcohol content can causes a gustatory disequilibrium affecting wine sensory perceptions leading to unbalanced wines. Hence, the object of this review is to enhance the knowledge on wine grape sugar composition, the alcohol perception on a sensorial level, as well as several technological practices that can be applied to reduce the wine alcohol content.

Full text

Beverages 2015, 1, 292-310; doi:10.3390/beverages1040292
beverages
ISSN 2306-5710
www.mdpi.com/journal/beverages
Review
From Sugar of Grape to Alcohol of Wine: Sensorial Impact of
Alcohol in Wine
António M. Jordão 1, Alice Vilela 2 and Fernanda Cosme 2,*
1 Agrarian Higher School, Polytechnic Institute of Viseu (CI & DETS), Estrada de Nelas,
Quinta da Alagoa, Ranhados, Viseu 3500-606, Portugal; E-Mail: antoniojordao@esav.ipv.pt
2 CQ-VR, Chemistry Research Centre, School of Life Sciences and Environment, Department of
Biology and Environment, Universidade de Trás-os-Montes e Alto Douro, Edifício de Enologia,
Apartado 1013, Vila Real 5001-801, Portugal; E-Mail: avimoura@utad.pt
* Author to whom correspondence should be addressed; E-Mail: fcosme@utad.pt;
Tel.: +351-259-350-657; Fax: +351-259-350-480.
Academic Editor: Lorenzo Stafford
Received: 30 August 2015 / Accepted: 23 October 2015 / Published: 2 November 2015
Abstract: The quality of grapes, as well as wine quality, flavor, stability, and sensorial
characteristics depends on the content and composition of several different groups of
compounds from grapes. One of these groups of compounds are sugars and consequently
the alcohol content quantified in wines after alcoholic fermentation. During grape berry
ripening, sucrose transported from the leaves is accumulated in the berry vacuoles as
glucose and fructose. The wine alcohol content continues to be a challenge in oenology, as
it is also the study of the role of chemosensory factors in alcohol intake and consumer
preferences. Several technical and scientific advances have occurred in recent years, such
as identification of receptors and other important molecules involved in the transduction
mechanisms of flavor. In addition, consumers know that wines with high alcohol content
can causes a gustatory disequilibrium affecting wine sensory perceptions leading to
unbalanced wines. Hence, the object of this review is to enhance the knowledge on wine
grape sugar composition, the alcohol perception on a sensorial level, as well as several
technological practices that can be applied to reduce the wine alcohol content.
Keywords: alcohol content; alcohol reduction technologies; grapes; sensory perception;
sugar accumulation; wine
OPEN ACCESS

Beverages 2015, 1 293
1. General Introduction
The sugar composition of berries has a key role in wine quality, since they determine the alcohol
content of the wines. Grape berry sugar composition and concentration change during grape ripening
and can be influenced by many factors, such as environment and viticulture management.
Alcohol is the most abundant volatile compound in wine and it can modify both the sensory
perception of aromatic attributes and the detection of volatile compounds [1]. Therefore, alcohol is
important for wine sensory sensations but also by their interaction with other wine components, such
as aromas [1] and tannins [2,3], also influencing wine viscosity and body [4] and our perceptions of
astringency, sourness, sweetness, aroma, and flavor [5].
In the last years, the alcohol content in wines has tended to increase, due to different factors. One of
them is the potential sugar increase in musts, attributed to the probable climate change [6,7]. However,
at the same time, a great number of consumers from several countries, especially from Europe, demand
more reduced alcohol beverages (9%–13% v/v) as a result of health and social concerns (i.e., traffic
penalties) [8–10]. The increasing alcohol levels in wine could be resolved using techniques to remove
or lower the wine alcohol content. However, it is important to know the limitations of these techniques
on the wine sensorial characteristics, as well as providing information related to wine quality and
consumer acceptance of these wines.
Mouthfeel and texture are the major determinants for consumer’s preference for foods, including
beverages [11–13]. Viscosity, density, and surface tension are the essential rheological properties
which affect the mouthfeel of liquid food products, such as wine. They also modify other sensory
properties like saltiness, sweetness, bitterness, flavor, and astringency [14–16]. It is important to
understand how and where the interactions are generated as they have impacts on the flavor perception
and the key sensory profile of food products. There are physical interactions between the components
in the food or beverage matrix influencing the volatiles release [17] and/or viscosity [18], and
multi-modal interactions resulting from the cognitive or psychological integration of the anatomically-
independent sensory systems [19].
Physical viscosity, density, and yield stress have also been used to give a more comprehensive
profile of the rheological properties of fluids [20]. While white wine alcohol concentration was found
to be highly correlated with the perceived intensity and physical measurements of viscosity and
density, the perceived viscosity and perceived density maxima were best described by quadratic and
cubic models, respectively [4]. Intensity maxima for viscosity and density occurred at 10% (v/v) and
12% (v/v) white wine alcohol concentration, respectively, although white wines of 7% (v/v) to
14% (v/v) alcohol concentration were not statistically differentiated for either attribute (perceived
viscosity and density) [4]. For example, alcohol is commonly utilized in composing various beverages
and flavored vodkas. For instance, in 2008, Finland Vodka Company noted a 30% increase in the sale
of flavored vodkas, which contain herb extracts and essences, plant distillates, fruits and their juices, and
volatile aromas [21]. According to the work of Pankiewicz and Jamroz [21], a link was found between
the concentrations of alcohol in pure vodka and in its blends with pear nectar and the perceived
sensory viscosity and density of the drink.

Beverages 2015, 1 294
Thus, the intention of this review is to contribute to a better knowledge on the grape sugar
composition, including the factors that influenced their accumulation during grape ripening, the alcohol
perception on sensorial level, as well as technological practical to reduce the wine alcohol content.
2. Grape Berry Composition—Sugars
Sugar accumulation in grape berries is an important phenomenon which has a great impact on the
amount of alcohol in wine. In addition, in berries, total sugar is also an important fruit quality factor in
table grapes. The predominant sugars that are present in grapes are glucose and fructose, with only
trace content of sucrose in grape berries of most cultivars. Only a few high-sucrose content cultivars
are detected in Vitis rotundifolia and hybrids between Vitis labrusca and Vitis vinifera [22–24].
Shiraishi et al. [25] identified two types of grapes based on sugar composition: hexose accumulators
for which the glucose/(fructose + sucrose) ratio was >0.8, and sucrose accumulators for which this
ratio was <0.8. According to Dai et al. [24], most Vitis vinifera cultivars have a glucose/fructose ratio
of 1 at maturity, while this ratio varies from 0.47 to 1.12 in wild species. In addition, only few a
species (Vitis champinii and Vitis doaniana) accumulate more glucose than fructose. Liu et al. [26]
analyzed sugar concentration of 98 different grape cultivars and concluded that glucose and fructose
were the predominant sugars in grape berries ranging from 45.86 to 122.89 mg/mL and from 47.64 to
131.04 mg/mL, respectively. Additionally, sucrose was present at trace amounts in most of the
cultivars studied (except for two cultivars of hybrids between Vitis labrusca and Vitis vinifera, which
contained large amounts of sucrose).
The accumulation of sugar in the form of glucose and fructose within the cellular medium,
specifically in the vacuoles, is one of the main features of the ripening process in grape berries and is a
major commercial consideration for the grape grower, winemaker, and dried grape producer. Thus,
sugar content is an indicator often used to assess ripeness and to mark the harvest. Moreover, as most
of the sugar is fermented to alcohol during the winemaking process, the measurement of sugar content,
the so-called “must weight”, allows the control of alcohol content in the wine.
3. Sugar Accumulation during Grape Ripening
A schematic representation of grape berry development, sugar uptake, and metabolism during grape
maturation is shown in Figure 1. Thus, during grape berry sugar accumulation, sucrose is produced
in leaves by photosynthetic carbon assimilation and is transported to the berry in the phloem [27].
Sucrose is loaded into the phloem by either a symplastic or apoplastic mechanism [28]. The presence
of an apoplastic step requires the involvement of membrane-located sugar transporter proteins
(“hexose transporters” in Figure 1) mediating the exit of sucrose from the phloem, and the uptake and
compartmentation of sugars across the plasma membrane and the tonoplast of flesh cells [29].

Beverages 2015, 1 295
Figure 1. Schematic representation of grape berry development, sugar uptake, and
metabolism during grape maturation. The curve indicates changes in berry size and two
possible pathways are indicated for sugar uptake and metabolism. Legend: (-----) berry
changes size. P
1
and V
1
—Hexose transporters; P
2
and V
2
—Sucrose transporters.
In the first phase of berry growth most of the sugar imported into the fruit is metabolized and grapes
contain relatively low levels of sugars. However, at véraison sugar accumulation begins and the
imported sucrose is converted into hexoses, which are stored in the vacuole. The grape berries
accumulate glucose and fructose in equal amounts at a relatively constant rate during ripening [30].
According to several authors [31,32], massive accumulation of glucose and fructose in the vacuoles of
mesocarp cells occurs after véraison and, twenty days after this period, the hexose content of the grape
berry is close to 1 M, with a glucose/fructose ratio of 1. Since sucrose is the major translocated sugar
in grape vine, the rapid accumulation of hexoses characterizing berry ripening must involve the
activity of invertases. Their expression is high at early stages of berry development, but it declines
greatly when hexose accumulation starts [28]. In addition, Hawker [33] found that invertase enzyme
activity in Sultana berries increased immediately after flowering and that the activity peaked 6–7
weeks later, at véraison, when the rapid accumulation of hexoses commenced. According to the same
author, another enzyme that might be involved in the breakdown of sucrose is sucrose synthase, which
also increases during véraison, but their maximal activity is low compared to the level of invertase
activity (200–300 times less). Invertases catalyze hydrolysis of sucrose provided by the phloem
conducting complex into glucose and fructose. Different invertase isoforms are localized in the cell
wall, cytoplasm, and vacuole. Hydrolysis of sucrose by cell wall invertase may promote unloading by
preventing its retrieval by the phloem, and by maintaining the sucrose concentration gradient.
4. Factors that Affect the Sugar Accumulation and Level in Grape Berries
Berry sugar accumulation is regulated by complex mechanisms. For example, the expression of
disaccharide transporter genes (DSTs) and monosaccharide transporter genes (MSTs), sugar
transporter proteins that mediate the exit of sucrose from the phloem and the uptake of sugars across
the plasma membrane and the tonoplast of flesh cells, may be affected by various parameters,

Beverages 2015, 1 296
including light, water, and ion status, wounding, fungal and bacterial attacks, and hormones [34–36].
According to several authors [24,37] sugar composition is mainly determined by genotype, and sugar
concentration is strongly affected by several factors, such as environment and cultural management.
For example, irrigation has a variable effect on sugar accumulation in the grape berries. Thus,
according to several studies [38–42], there is a variation in sugar concentration (increase, decrease or
no changes) as a result of irrigation practice. Esteban et al. [39] analyzed the impact of water
availability on the yield and must composition of Vitis vinifera L. cv. Tempranillo grapes during
three-year period and concluded that total soluble solids, and the concentration of glucose and fructose
were significantly higher in the irrigated vines than in the non-irrigated vines, mainly towards the end
of ripening. On the other hand, Intrigliolo et al. [41] consider that the effects of irrigation on must and
wine composition are largely dependent of climatic characteristics of each year, namely by the
different rainfall amount and crop levels.
For several researchers [43,44] temperature is an important environmental factor that affects the
grape sugar accumulation. For temperatures above 25 °C, net photosynthesis decreases even at
constant sun exposure [45]. In addition, for temperatures above 30 °C, several authors [46,47] have
reported a reduction of berry size and weight, and metabolic processes and sugar accumulation may
completely stop. However, although high temperatures accelerate grape maturation, according to
Coombe [47] temperature effects on final sugar accumulation are reported to be relatively small.
Higher temperatures (30 °C) may lead to higher suspended solid concentrations, but Brix levels higher
than 24–25 Brix (238.2 g/L of sugar to 249.7 g/L of sugar; 14.15% (v/v) estimated alcohol to 14.84%
(v/v) estimated alcohol) are likely not due to photosynthesis and sugar transport from leaves and wood,
but to concentration by evaporation [48,49]. In the last years, the alcohol content of wines tended to
increase, due to different factors. One of them is the sugar increase in grapes and must, attributed to the
climate change [50]. However, according to [44], the extremely high sugar concentrations reached at
harvest today, especially in warm climates, may be rather associated with the desire to optimize
technical or polyphenolic and/or aromatic maturity. Finally, moderate water deficit, UV-B radiation,
and low temperatures (below 30 °C), have a positive effect during grape ripening by the increasing of
sugar content in grape berries [51,52]. Duchêne and Schneider [53] showed that, over the last 30 years,
the estimated alcohol level of Riesling grapes in Alsace, increased 2.5% (v/v) due to warmer ripening
periods and earlier phenology. Additionally, Godden and Gishen [54] observed in Australian wines an
increase in the alcohol content from 12.3% (v/v) to 13.9% (v/v) for red wines and from 12.2% (v/v) to
13.2% (v/v) for white wines, between 1984 and 2004.
5. Psychophysiology of Alcohol Perception
Taste strongly influences food intake [55], including alcohol consumption [56,57]. Alcohol
activates olfactory, taste, and chemesthetic receptors and each modality is carried centrally by different
nerves; these inputs affect the perception evoked by alcohol. Chemesthesis is defined as the chemical
sensibility of the skin and mucous membranes. Chemesthetic sensations arise when chemical
compounds activate receptors associated with other senses that mediate pain, touch, and thermal
perception. Examples of chemesthetic sensations include the burn-like irritation from chili pepper, the
coolness of menthol in mouthwashes and topical analgesic creams, the stinging or tingling of

Beverages 2015, 1 297
carbonation in the nose and mouth, and the tear-induction of onions. The oral consumption of alcohol
by humans is accompanied by chemosensory perception of flavor, which plays an important role in its
acceptance or rejection. Three independent sensory systems, taste, olfaction, and chemosensory
irritation, are involved in the perception of flavor in food and in wine in particular (Figure 2) [58].
Figure 2. Mechanism of flavor perception in food and wine intake. Adapted from
Redondo et al. [59].
As reported by Allen et al. [60], humans perceive alcohol as a combination of sweet and bitter tastes
odors (Figure 3), and oral irritation (burning sensation). However, several researchers like Lanier et al. [58]
found that some people describe experiences of more bitterness and less sweetness when drinking
alcohol, and this directly relates to the genes they have inherited and individual differences in
bitterness and sweetness are predictors of alcohol liking and intake in young adults. In addition, the
perception of bitterness and sweetness also vary as a function of alcohol concentration [61,62].

Figure 3. Diagram showing the signal transduction pathway of bitter taste. A, taste bud;
B, taste cell; and C, neuron attached to B. Adapted from Hldavis4 [63].

Beverages 2015, 1 298
Multiple studies [64,65] have linked variation in TAS2R (taste receptor, type 2) bitter receptor
genes to alcohol intake. An important gene contributing to PTC (the ability to taste the bitterness of
phenylthiocarbamide) perception has been identified [66]. The gene (TAS2R38—taste receptor,
type 2, member 38), located on chromosome 7q36, is a member of the bitter taste receptor family.
There are two common molecular forms (proline-alanine-valine (PAV) and alanine-valine-isoleucine
(AVI)) of this receptor defined by three nucleotide polymorphisms that result in three amino acid
substitutions: Pro49Ala, Ala262Val, and Val296Ile. Duffy et al. [67] reported that TAS2R38
haplotypes are associated with alcoholic intake, with AVI homozygotes, who perceive less bitterness
from the bitter compound propylthiouracil (6-n-propylthiouracil (PROP) is a thiouracil-derived drug
used to treat hyperthyroidism, including Graves’ disease, by decreasing the amount of thyroid hormone
produced by the thyroid gland) consuming, significantly, more alcoholic drinks than heterozygotes or
PAV homozygotes. More recently, Dotson et al. [68] reported associations between TAS2R38 and
TAS2R13 polymorphisms and alcohol intake derived from the Alcohol Use Disorders Identification
Test (AUDIT) in head and neck cancer patients.
In addition, to bitter and sweet sensations, as we mentioned before, alcohol also causes irritation
commonly described as burning or stinging [58]. Burning sensations in the mouth are due, in part,
to activation of the transient receptor potential vanilloid receptor 1 (TRPV1) that is activated by
noxious heat, capsaicin [69,70], and alcohol even at relatively low concentrations (0.1% to 3% v/v) [71].
When the TRPV1 gene is knocked out in mice, knockouts have a higher preference for alcohol and
consume more than wild-type mice [72]. Collectively, these data suggest the TRPV1 receptor likely
plays a role in the perception and acceptability of alcohol.
Many factors underlie the role that alcohol flavor plays in the development of alcohol preference
and consumption patterns. Such factors include the activation of peripheral chemoreceptors by
alcohol [70]; central mechanisms that mediate the hedonic responses to alcohol flavor [73]; learned
associations of alcohol’s sensory attributes and its post digestive effects and early postnatal exposure
to alcohol flavor [74,75]; and genetically determined individual variation in chemosensation [21,61].
The study of the role of chemosensory factors in alcohol intake and preferences is of special interest
because the past decade has witnessed significant technical and scientific advances, which include
identification of receptors and other key molecules involved in the transduction mechanisms of
olfaction [76,77], chemosensory irritation [78], and taste [79–82].
6. The Effects of Ethanol on the Body and Other Sensory Characteristics of Wines
The terms “body” and “fullness” are wine attributes frequently used to describe the in-mouth
impression of both red and white table wines [83]. Wines are regularly classified as being light,
medium, or full bodied. Presumably as wines of different style appeal to different market segments,
and are consumed in different social and culinary contexts. However, despite its widespread use and
application, there appears to be a lack of common understanding within the wine trade as to what
sensory aspects contribute to wine body. Most importantly, there appears to be no agreed position on
the necessary conditions for “fullness” in wine or other alcoholic beverages. Despite the apparent lack
of agreement on what constitutes body in wine, Gawel [84] showed that experienced wine tasters, with
extensive practical training, had an equivalent understanding of “body” in white wines, and considered

Beverages 2015, 1 299
the feature important in distinguishing between the wines. It has long been speculated that alcohol
strongly contributes to palate fullness in white wine [85]. Pickering et al. [4] were the first to formally
test this premise. They found that the perceived density of a de-alcoholized wine generally increased
with increasing alcohol over a 14% (v/v) range, while its perceived viscosity was highest at 10% (v/v)
ethanol. Later work [86] using model wine solutions showed a positive monotonic effect of alcohol
content on both perceived viscosity and density over the same alcohol range, further supporting the
existence of a positive relationship between alcohol content and fullness in white wine.
The contribution of ethanol to wine sensory properties extends beyond that of possibly enhancing
fullness. Ethanol affects the headspace concentrations of many wine volatiles [87], and also contributes
to sweetness [88]. Furthermore, ethanol induced palate warmth and perceived viscosity may indirectly
affect both aroma and flavor perception. Moreover, according to the work of Joshi and Sandhu [89] the
results of sensory evaluation of different vermouths prepared with different ethanol concentrations,
sugar levels and spices extract showed significant differences for various sensory quality parameters.
The data obtained revealed that for color and appearance, 12% (v/v) and 15% (v/v) of alcohol with
2.5% (w/v) spices extract scored better, but for aroma virtually all the treatments were comparable.
However, in total acidity vermouth with 18% (v/v) ethanol scored lower than those with 12% (v/v) and
15% (v/v). In bitterness and astringency, vermouths of all the treatments were comparable. In overall
quality, apple vermouth with 15% (v/v) ethanol, 2.5% (w/v) spices extract, and 4% (v/v) sugar content
scored the highest. So, bitterness, astringency, and total acidity are influenced by the alcohol vermouth
concentration. However, for Noble [90], the higher concentrations of alcohol in wines contribute to
enhance bitterness intensity, but have no effect on perception of astringency.
7. Technological Practical to Reduce the Wine Alcohol Content and Their Sensorial Impact
Alcohol fermentation is done by yeast and some types of bacteria. These microorganisms convert
berry sugars into ethyl alcohol and carbon dioxide. Alcoholic fermentation begins after glucose enters
the yeast cell (Saccharomyces cerevisiae). The glucose is broken down into pyruvic acid, which is then
converted to carbon dioxide, ethanol, and energy for the cell. Humans have taken advantage of this
process in making wine, bread and beer.
Nowadays, the market in general, appreciated full body red wines with intense and complex flavor
profiles produced from grapes with adequate phenolic ripeness, optimal flavor balance and lower
acidity [91–95], but the juice from such grapes also contains high sugar content and consequently leads
to wines with high alcohol contents (14%–16%, v/v) [91,96]. Alcohol taste near or above this
threshold is described as bitter or as sweet and/or sour [88]. Nevertheless, in recent years there is a
consumer demand for wines with lower alcohol content (9%–13%, v/v), that apparently are healthier
since the consumer’s attitudes are changing [8,9,97]. In addition, consumers also perceive that high
alcohol levels affects wine sensory perceptions, leading to unbalanced wines. On the other hand, wines
made from grapes with high sugar levels will probably show low acidity and poor aromatic notes.
These wines can be perceived as more hot on the palate and the volatility and sensory perception of
other volatile compounds affects detection thresholds [5]. Additionally, in some countries, winemakers
have to pay taxes when alcohol content in wine is over 14.5% (v/v), increasing in this way the wine
final price [97].

Beverages 2015, 1 300
Wines with higher alcohol levels changed their wine sensory profile [98], partly by decreasing the
volatility of wine aroma compounds, since up to a certain level of alcohol a decrease in fruity aromas
was observed, being that many of these wines considered out of balance, and dominated by
alcohol-associated attributes [1]. The effect of alcohol on the sensory perception of fruitiness from a
mixture composed by nine fruity compounds at the maximum concentrations found in the wines was
evaluated by Escudero et al. [99]. According to these authors, when there is no alcohol in the mixture,
the smell is strong; however, the intensity of the smell decreases with the content of alcohol in the
mixture being at 14.5% (v/v) no longer perceived. It was also observed by other authors [2,5] that the
bitterness intensity was higher when the alcohol content increased and astringency decreased linearly
when the content of alcohol increased, too. However, Noble [90] showed also that higher
concentrations of alcohol enhance bitterness intensity in wines, but observed no effect on perception of
astringency. According to the author [90], subjects with high salivary flow rates perceived maximum
intensity sooner and reported shorter duration of both bitterness and astringency than low-flow judges.
In spite of the final quality and acceptance of wines, musts with high sugar content usually show
additional oenological problems, as difficulty to carry out alcoholic fermentation, with sluggish
fermentation, and even fermentation stops [100]. This fact gives origin to new problems, due to the
microbiological instability of wines with high levels of residual sugars. In an effort to meet the
demands of consumers for wines with lower alcohol, winemakers are searching for technological
strategies to low the wine alcohol content. There are some technical procedures to reduce the alcohol
content that could be done either by reducing the concentration of sugar present in grapes [50,101], or
by removing alcohol from wine [92].
The grape sugar reduction involves harvesting grapes at an earlier stage of ripening [94]. However,
the wine composition and quality changed due to fewer aromas flavor and color intensity, and
increased acidity.
During alcoholic fermentation, respiration of sugars by non-Saccharomyces yeasts has been
recently proposed for lowering alcohol levels in wine. Development of industrial fermentation
processes based on such an approach requires the identification of yeast strains able to grow and
respire under the relatively severe conditions found in grape must. In a work performed by
Quirós et al. [102], physiological features of some strains of Metschnikowia pulcherrima and
Kluyveromyces yeasts that constitute the main part of the microbiota of sound ripe grapes, and are
known to predominate during the initial stages of wine fermentation [103], suggest that they are
appropriate for lowering alcohol yields by respiration. Although the concentration of molecular oxygen
is particularly low during fermentation, mainly due to carbon dioxide release, several practices
employed during the first stages of winemaking such as pumping over, délestage, or
macrooxigenation, can increase oxygen concentration. These, or ad hoc oxygenation practices, would
allow for the partial respiration of grape sugars by the appropriate yeast strains. However, in a regular
fermentation, S. cerevisiae usually dominates the fermentation, being this practice somewhat difficult
and with poorer results.
For using S. cerevisiae strains in alcohol reduction, different techniques have been applied like
expression of NADH-dependent lactate dehydrogenase or a bacterial NADH oxidase in yeast [104].
Although both techniques reduced alcohol production, the wine quality has been spoiled due to
the detrimental byproducts, like lactic acid, acetaldehyde, and some oxidized compounds [104].

Beverages 2015, 1 301
Non-genetically modified (non-GM) approaches, such as evolutionary engineering, has been practiced
thanks to adaptive evolution [105]. Adaptive evolution can be applied by diversion of carbons towards
the pentose phosphate (PP) pathway leading to lower availability of carbons for ethanol production by
elimination of carbons in the form of carbon dioxide and reduced acetate production and increased
ester formation. Another approach is evolutionary engineered yeasts with sugars diverted towards
glycerol and 2,3-butanediol. According to Tilloy et al. [104] these engineered yeasts have ability to
reduce the alcohol content of wine by 0.5% to 1% (v/v).
It is also possible to reduce the sugar in musts to obtain wines with a slight alcohol reduction by the
use a several technologies, namely nanofiltration. Thus, according to García-Martín et al. [50] the
sugar reduction in must by using the nanofiltration technology resulted in a satisfactory alcohol
reduction in the resulting wine, but with a slight loss in the color and aroma.
Several membrane technologies have also been developed for alcohol removal from wine, in the
winery. They are reported to allow the reduction of the alcohol content under soft conditions in order
to try to preserve the sensory characteristic of the original wine [8,92,106]. Semi-permeable
membranes by which alcohol can be separated from wine have been available since the 1970s [92].
The benefit of membrane technologies (nanofiltration, membrane contactor, reverse osmosis, and other
membrane techniques) is the low operations cost, and the advantage to work at low to moderate
temperatures, being limited by the negative effects on wine aroma chemical reactions or degradation [107].
This procedure will be used to reduce only 1% or 2% (v/v) of the alcohol content in order to obtain
more balanced wines with complete aromatic potential and phenolic ripeness [93,108], as established
by the European regulation (EC Reg. 606/2009) [109] reduction of the actual alcoholic strength by
volume may not be more than 2% (v/v), but more recently this limit has been changed. Thus,
according to the Commission Regulation (UE) N 144/2013 [110] the alcohol content may be reduced
by a maximum of 20% (v/v), OIV-ECO 433-2012 [111]. The separating techniques that can be used to
reduce the alcohol content according to OIV (Resolution OIV-Oeno 394A-2012) [112] are: partial
vacuum evaporation, membrane techniques, and distillation. Of these, the most used in the wineries are
the spinning cone column and reverse osmosis system to produce lower alcohol wines or to adjust the
ethanol content [3,92]. Reverse osmosis, is a membrane separation process that is probably the most
successfully-employed procedure for partial dealcoholization [113]. The results showed that this
technique has the advantage of having a minimal negative influence on wine taste, by modifying only
the wine alcohol content while the other parameters remained unaffected, since it is performed at low
temperature [92]. Reverse osmosis could be a technique for improving a wine’s balance in regions
where wines can reach high alcohol content. However, this wine alcohol reduction process could also
negatively affect the wine sensorial quality, leading in the worst cases to an unacceptability of the
wine, by changing the complex equilibrium among organic compounds responsible for wine taste,
flavor and mouth feel. The observed modifications in reduced alcohol wine sensorial characteristics
could be due to the reduction in alcohol content, which plays an important role in wine taste [5], mouth
feel [2,4], and olfactory wine properties [1,99]; and in the losses of volatile and polyphenolic
compounds, during the alcohol reduction process [106,114]. Removal of alcohol from wine reduced
fruity aromas, and enhanced vegetative and sweaty aromas in white wines [93]. According to King and
Heymann [115] reducing the alcohol content of oaked white wine using spinning cone technology
results in a minimal impact on sensory composition and consumer preferences since no perceptible

Beverages 2015, 1 302
changes to the sensory profile were observed. These authors showed that panelists and consumers were
unable to detect changes among wines with a 1% (v/v) difference. This work suggests that the use of
technology to partially reduce the white wine alcohol content without reducing the wine quality is of
beneficial use to the wine industry. However, Meillon et al. [3], using the reverse osmosis treatment to
reduce the wine alcoholic degree of Merlot and Syrah wines, showed that the wine sensory perception
and their appreciation/acceptability by consumers was modified, particularly a decrease in the
perception of the wine balance was observed. According to the same authors, a significant impact on
the sensory properties of red wines with a decrease in the perception of hotness, bitterness, aromas, and
persistency in the mouth was observed, and also an increase in the perception of astringency and a
decrease in the perception of wine complexity. Generally, alcohol reduction was less well accepted for
red than for white wines, and it was also variable from one grape variety to another one. In this way,
there are several kinds of interactions between alcohol and wine components that make difficult the
generalization of alcohol reduction effect on the sensory perception of wines [3]. Lisanti et al. [116]
concluded that wine alcohol reduction using the membrane contactor technique affected the red wine
sensorial properties. The most reduced olfactory notes were those of cherry and red fruits, particularly
in wine with 5% (v/v) alcohol reduction. The alcohol reduction process also increased the intensity of
astringency, bitterness, and acidity. However, according to the same authors an alcohol reduction of
2% (v/v), has slightly affected the wine sensory profile.
8. Final Remarks
Grape sugar concentration is a parameter to predict grape and wine quality. However, in recent
years, the sugar concentration has increased in grapes, attributed to climate change; therefore, the
alcohol content of wines tended to increase. The high sugar concentrations reached at harvest today
may, rather, be associated with the desire to optimize technical or polyphenolic and/or aromatic
maturity.
Though, consumption of alcohol beverages is accompanied by chemosensory perception of flavor,
which is an important factor for acceptance or rejection. Thus, the main factors for selection of the wine
alcohol-reducing technique are maintaining quality, in terms of flavor, in the final wine, and lowest cost.
The request for less alcoholic wines has led to technological innovations to low alcohol content
without changing the wine sensorial profile.
Author Contributions
António M. Jordão, Alice Vilela and Fernanda Cosme equally contributed to the paper.
Conflicts of Interest
The authors declare no conflict of interest.

Beverages 2015, 1 303
References
1. Goldner, M.C.; Zamora, M.C.; di Leo Lira, P.; Gianninoto, H.; Bandoni, A. Effect of ethanol
level in the perception of aroma attributes and the detection of volatile compounds in red wine.
J. Sens. Stud. 2009, 24, 243–257.
2. Fontoin, H.; Saucier, C.; Teissedre, P.L.; Glories, Y. Effect of pH, ethanol and acidity on
astringency and bitterness of grape seed tannin oligomers in model wine solution. Food Qual.
Preference 2008, 19, 286–291.
3. Meillon, S.; Urbano, C.; Schlich, P. Contribution of the temporal dominance of sensations
(TDS) method to the sensory description of subtle differences in partially dealcoholized red
wines. Food Qual. Preference 2009, 20, 490–499.
4. Pickering, G.J.; Heatherbell, D.A.; Vanhanen, L.P.; Barnes, M.F. The effect of ethanol
concentration on the temporal perception of viscosity and density in white wine. Am. J. Enol.
Vitic. 1998, 49, 306–318.
5. Fischer, U.; Noble, A.C. The effect of ethanol, catechin concentration, and pH on sourness and
bitterness of wine. Am. J. Enol. Vitic. 1994, 45, 6–10.
6. Jones, G.V.; White, M.A.; Cooper, O.R; Storchmann, K. Climate change and global wine quality.
Clim. Chang. 2005, 73, 319–343.
7. Koufos, G.; Mavromatis, T.; Koundouras, S.; Fyllasd, N.M.; Jones, G.V. Viticulture-climate
relationships in Greece: The impacts of recent climate trends on harvest date variation. Int. J.
Climatol. 2013, 34, 1445–1459.
8. Labanda, J.; Vichi, S.; Llorens, J.; López-Tamames, E. Membrane separation technology for the
reduction of alcoholic degree of a white model wine. LWT Food Sci. Technol. 2009, 42, 1390–1395.
9. Masson, J.; Aurier, P.; D’hauteville, F. Effects of non-sensory cues on perceived quality: The
case of low-alcohol wine. Int. J. Wine Bus. Res. 2008, 20, 215–229.
10. Saliba, A.J.; Ovington, L.A.; Moran, C.C. Consumer demand for low-alcohol wine in an
Australian sample. Int. J. Wine Res. 2013, 5, 1–8.
11. Szczesniak, A.S. Classification of mouthfeel characteristics of beverages. In Food Rheology and
Texture; Sherman, P., Ed.; Academic Press: London, UK, 1979; pp. 1–20.
12. Szczesniak, A.S. Psychorheology and texture as factors controlling the consumer acceptance of
food. Cereal Foods World 1990, 35, 1201–1205.
13. Noble, A.C.; Arnold, R.A.; Buechsenstein, J.; Leach, E.J.; Schmidt, J.O.; Stern, P.M.
Modification of a standardized system of wine aroma terminology. Am. J. Enol. Vitic. 1987, 38,
143–146.
14. Smith, A.K.; June, H.; Noble, A.C. Effects of viscosity on the bitterness and astringency of grape
seed tannin. Food Qual. Preference 1996, 7, 161–166.
15. Hollowood, T.A.; Linforth, R.S.T.; Taylor, A.J. The effect of viscosity on the perception of
flavour. Chem. Senses 2002, 27, 583–589.
16. Yanniotis, S.; Kotseridis, G.; Orfanidou, A.; Petraki, A. Effect of ethanol, dry extract and
glycerol on the viscosity of wine. J. Food Eng. 2007, 81, 399–403.
17. Da Porto, C.; Cordaro, F.; Marcassa, N. Effects of carbohydrate and noncarbohydrate sweeteners
on the orange spirit volatile compounds. Food Sci. Technol. 2006, 39, 159–165.

Beverages 2015, 1 304
18. Walker, S.; Prescott, J. The influence of solution viscosity and different viscosifying agents of
apple juice flavour. J. Sens. Stud. 2000, 15, 285–307.
19. Dalton, P.; Doolittle, N.; Nagata, H.; Breslin, P.A.S. The merging of the senses: Integration of
subthreshold taste and smell. Nat. Neurosci. 2000, 3, 431–432
20. Cichero, J.A.Y.; Jackson, O.J.; Halley, P.J.; Murdoch, B.E. How thick is thick? Multicenter study
of the rheological and material property characteristics of meal time fluids and videofluoroscopy
fluids. Dysphagia 2000, 15, 188–200.
21. Pankiewicz, U.; Jamroz, J. Evaluation of Physicochemical and Sensory Properties of Ethanol
Blended with Pear Nectar. Czech J. Food Sci. 2013, 31, 66–71.
22. Carroll, D.E.; Hoover, M.W.; Nesbitt, W.B. Sugar and organic acid concentrations in cultivars of
muscadine grapes. J. Am. Soc. Hortic. Sci. 1971, 96, 737–740.
23. Shiraishi, M. Three descriptors for sugars to evaluate grape germplasm. Euphytica 1993, 71,
99–106.
24. Dai, Z.W.; Ollat, N.; Gomès, E.; Decroocq, S.; Tandonnet, J.-P.; Bordenave, L.; Pieri, P.; Hilbert, G.;
Kappel, C.; van Leeuwen, C.; et al. Ecophysiological, genetic, and molecular causes of variation
in grape berry weight and composition: A review. Am. J. Enol. Vitic. 2011, 62, 413–425.
25. Shiraishi, M.; Fujishima, H.; Chijiwa, H. Evaluation of table grape genetic resources for sugar,
organic acid, and amino acid composition of berries. Euphytica 2010, 174, 1–13.
26. Liu, H.F.; Wu, B.H.; Fan, P.G.; Li, S.H.; Li, L.S. Sugar and acid concentrations in 98 grape
cultivars analyzed by principal component analysis. J. Sci. Food Agric. 2006, 86, 1526–1536.
27. Conde, B.C.; Silva, P.; Fontes, N.; Dias, A.C.P.; Tavares, R.M.; Sousa, M.J.; Agasse, A.; Delrot, S.;
Geros, H. Biochemical changes throughout grape berry development and fruit and wine quality.
Food 2007, 1, 1–22.
28. Boss, P.K.; Davies, C. Molecular biology of sugar and anthocyanin accumulation in grape berries.
In Molecular Biology and Biotechnology of the Grapevine; Roubelakis-Angelakis, K.A, Ed.;
Kluwer Academic Publishers: Dordrecht, The Netherlands, 2001; pp. 1–33.
29. Williams, L.E.; Lemoine, R.; Sauer, N. Sugar transporters in higher plants—A diversity of roles
and complex regulation. Trends Plant Sci. 2000, 5, 283–290.
30. Robinson, S.P.; Davies, C. Molecular biology of grape berry ripening. Aust. J. Grape Wine Res.
2000, 6, 175–188.
31. Coombe, B.G. Research on Development and Ripening of the Grape Berry. Am. J. Enol. Vitic.
1992, 43, 101–110.
32. Fillion, L.; Ageorges, A.; Picaud, S.; Coutos-Thevenot, P.; Lemoine, R.; Romieu, C.; Delrot, S.
Cloning and expression of a hexose transporter gene expressed during the ripening of grape berry.
Plant Physiol. 1999, 120, 1083–1093.
33. Hawker, J.S. Changes in the activities of enzymes concerned with sugar metabolism during the
development of grape berries. Phytochemistry 1969, 8, 9–17.
34. Kühn, C.; Franceschi, V.R.; Schulz, A.; Lemoine, R.; Frommer, W.B. Macromolecular
trafficking indicated by localization and turnover of sucrose transporters in enucleate sieve
elements. Science 1997, 275, 1298–1300.
35. Delrot, S.; Atanassova, R.; Maurousset, L. Regulation of sugar, amino acid and peptide plant
membrane transporters. Biochim. Biophys. Acta 2000, 1465, 281–306.

Beverages 2015, 1 305
36. Octave, S.; Emborabé, B.E.; Fleurat-Lessard, P.; Bergès, T.; Roblin, G. Modifications of plant
cell activities by polypeptides secreted by Eutypa lata, a vineyard fungal pathogen. Physiol. Plant.
2006, 128, 103–115.
37. Esteban, M.A.; Villanueva, M.J.; Lissarrague, J.R. Relalationships between different berry
components in Tempranillo (Vitis vinifera L.) grapes from irrigated and non-irrigated vines
during ripening. J. Sci. Food Agric. 2002, 82, 1136–1146.
38. Jordão, A.M.; Ricardo-da-Silva, J.M.; Laureano, O. Influência da rega na composição fenólica
das uvas tintas da casta Touriga Francesa (Vitis vinifera L.). Cienc. Tecnol. Aliment. 1998, 2,
60–73.
39. Esteban, M.A.; Villanueva, M.J.; Lissarrague, J.R. Effect of Irrigation on Changes in Berry
Composition of Tempranillo during Maturation. Sugars, Organic Acids, and Mineral Elements.
Am. J. Enol. Vitic. 1999, 50, 418–434.
40. Orts, M.L.; Martínez-Cutillas, A.; López-Roca, J.M.; Gómez-Plaza, E. Effect of moderate
irrigation on grape composition during ripening. J. Agric. Res. 2005, 3, 352–361.
41. Intrigliolo, D.S.; Castel, J.R. Effects of Irrigation on the Performance of Grapevine cv.
Tempranillo in Requena. Am. J. Enol. Vitic. 2008, 59, 30–38.
42. Van Leeuwen, C.; Tregoat, O.; Choné, X.; Bois, B.; Pernet, D.; Gaudillère, J.-P. Vine water
status is a key factor in grape ripening and vintage quality for red bordeaux wine. How can it be
assessed for vineyard management purposes? J. Int. Sci. Vigne Vin. 2009, 43, 121–134.
43. Hawker, J.S. Effect of temperature on lipid, starch and enzymes of starch metabolism in grape,
tomato and broad bean-leaves. Phytochemistry 1982, 21, 33–36.
44. De Orduña, R. Climate change associated effects on grape and wine quality and production.
Food Res. Int. 2010, 43, 1844–1855.
45. Huglin, P.; Schneider, C. Biologie et Ecologie de la Vigne; Tec & Doc Lavoisier: Commune,
France, 1998.
46. Kriedemann, P.; Smart, R. Effect of irradiance, temperature and leaf water potential on
photosynthesis of vine leaves. Photosynthetica 1971, 5, 6–15.
47. Coombe, B. Influence of temperature on composition and quality of grapes. In ISHS Acta
Horticulturae, Proceedings of the International Symposium on Grapevine Canopy and Vigor
Management, Davis, CA, USA, 14 August 1986; Volume XXII IHC, pp. 23–35.
48. Keller, M. Managing grapevines to optimise fruit development in a challenging environment: A
climate change primer for viticulturists. Aust. J. Grape Wine Res. 2009, 16, 56–69.
49. Keller, M. The Science of Grapevines: Anatomy and Physiology; Academic Press: New York,
NY, USA, 2010.
50. García-Martín, N.; Perez-Magariño, S.; Ortega-Heras, M.; González-Huerta, C.; Mihnea, M.;
González-Sanjosé, M.L.; Palacio, L.; Prádanos, P.; Hernández, A. Sugar reduction in musts
with nanofiltration membranes to obtain low alcohol-content wines. Sep. Purif. Technol. 2010,
76, 158–170.
51. Castellarin, S.; Matthews, M.; Gaspero, G.; Gambetta, G. Water deficits accelerate ripening and
induce changes in gene expression regulating flavonoid biosynthesis in grape berries. Planta
2007, 227, 101–112.

Beverages 2015, 1 306
52. Berli, F.J.; Moreno, D.; Piccoli, P.; Hespanhol-Viana, L.; Silva, M.F.; Bressan-Smith, R.;
Cavagnaro, J.B.; Bottini, R. Abscisic acid is involved in the response of grape (Vitis vinifera L.)
cv. Malbec leaf tissues to ultraviolet-B radiation by enhancing ultraviolet-absorbing compounds,
antioxidant enzymes and membrane sterols. Plant Cell Environ. 2010, 33, 1–10.
53. Duchêne, E.; Schneider, C. Grapevine and climatic changes: A glance at the situation in Alsace.
Agron. Sustain. Dev. 2005, 24, 93–99.
54. Godden, P.; Gishen M. Trends in the composition of Australian wine. Aust. N. Z. Wine Ind. J.
2005, 20, 21–46.
55. Glanz, K.; Basil, M.; Maibach, E.; Goldberg, J.; Snyder, D. Why Americans eat what they do:
Taste, nutrition, cost, convenience, and weight control concerns as influences on food
consumption. J. Am. Diet. Assoc. 1998, 98, 1118–1126.
56. Moore, M.; Weiss, S. Reasons for non-drinking among Israeli adolescents of four religions.
Drug Alcohol Depend. 1995, 38, 45–50.
57. Higgs, S.; Stafford, L.D.; Attwood, A.S.; Walker, S.C.; Terry, P. Cues that signal the alcohol
content of a beverage and their effectiveness at altering drinking rates in young social drinkers.
Alcohol Alcohol. 2008, 43, 630–635.
58. Lanier, S.A.; Hayes, J.E.; Duffy, V.B. Sweet and bitter tastes of alcoholic beverages mediate
alcohol intake in of-age undergraduates. Physiol. Behav. 2005, 83, 821–831.
59. Redondo, N.; Gómez-Martíneza, S.; Marcos, A. Review Article—Sensory attributes of soft
drinks and their influence on consumers’ preferences. Food Funct. 2014, 5, 1686–1694.
60. Allen, A.L.; Hayes, J.E.; McGeary, J.E. Polymorphisms in TRPV1 and TAS2Rs associate with
sensations from sampled ethanol. Alcohol. Clin. Exp. Res. 2014, 38, 2550–2560.
61. Bartoshuk, L.M.; Conner, E.; Grubin, D.; Karrer, T.; Kochenbach, K.; Palsco, M.; Snow, D.;
Pelchat, M.; Danovski, S. PROP supertasters and the perception of ethyl alcohol. Chem. Senses
1993, 18, 526–527.
62. Mattes, R.D.; DiMeglio, D. Ethanol perception and ingestion. Physiol. Behav. 2001, 72, 217–229.
63. Hldavis4. Own Work & Template: Purves, Dale. Taste Receptors and the Transduction of Taste
Signals. U.S. National Library of Medicine, n.d. Web. May–June 2015. Licensed under CC
BY-SA 4.0 via Wikimedia Commons. Available online: https://commons.wikimedia.org/wiki/
File:Signal_Transaction_of_Taste;_Bitter.svg#/media/File:Signal_Transaction_of_Taste;_Bitter.sv
g (accessed on 20 June 2015).
64. Wooding, S.; Kim, U.K.; Bamshad, M.J.; Larsen, J.; Jorde, L.B.; Drayna, D. Natural Selection
and Molecular Evolution in PTC, a Bitter-Taste Receptor Gene. Am. J. Hum. Genet. 2004, 74,
637–646.
65. Drayna, D.; Coon, H.; Kim, U.K.; Elsner, T.; Cromer, K.; Otterud, B.; Baird, L.; Peiffer, A.P.;
Leppert, M. Genetic analysis of a complex trait in the Utah Genetic Reference Project: A major
locus for PTC taste ability on chromosome 7q and a secondary locus on chromosome 16p.
Hum. Genet. 2003, 112, 567–572.
66. Kim, U.K.; Jorgenson, E.; Coon, H.; Leppert, M.; Risch, N.; Drayna, D. Positional cloning of the
human quantitative trait locus underlying taste sensitivity to phenylthiocarbamide. Science 2003,
299, 1221–1225.

Beverages 2015, 1 307
67. Duffy, V.B.; Davidson, A.C.; Kidd, J.R.; Kidd, K.K.; Speed, W.C.; Pakstis, A.J.; Reed, D.R.;
Snyder, D.J.; Bartoshuk, L.M. Bitter receptor gene (TAS2R38), 6-n-propylthiouracil (PROP)
bitterness and alcohol intake. Alcohol. Clin. Exp. Res. 2004, 28, 1629–1637.
68. Dotson, C.D.; Wallace, M.R.; Bartoshuk, L.M.; Logan, H.L. Variation in the gene TAS2R13
is associated with differences in alcohol consumption in patients with head and neck cancer.
Chem. Senses 2012, 37, 737–744.
69. Tominaga, M.; Caterina, M.J.; Malmberg, A.B.; Rosen, T.A.; Gilbert, H.; Skinner, K.;
Raumann, B.E.; Basbaum, A.I.; Julius, D. The cloned capsaicin receptor integrates multiple
pain-producing stimuli. Neuron 1998, 21, 531–543.
70. Caterina, M.J.; Rosen, T.A.; Tominaga, M.; Brake, A.J.; Julius, D. A capsaicin-receptor
homologue with a high threshold for noxious heat. Nature 1999, 398, 436–441.
71. Trevisani, M.; Smart, D.; Gunthorpe, M.J.; Tognetto, M.; Barbieri, M.; Campi, B.; Amadesi, S.;
Gray, J.; Jerman, J.C.; Brough, S.J.; et al. Ethanol elicits and potentiates nociceptor responses via
the vanilloid receptor-1. Nat. Neurosci. 2002, 5, 546–551.
72. Blednov, Y.; Harris, R. Deletion of vanilloid receptor (TRPV1) in mice alters behavioral effects
of ethanol. Neuropharmacology 2009, 56, 814–820.
73. Ferraro, F.M.; Hill, K.G.; Kaczmarek, H.J.; Coonfield, D.L.; Kiefer, S.W. Naltrexone modifies
the palatability of basic tastes and alcohol in outbred male rats. Alcohol 2002, 27, 107–114.
74. Mennella, J.A. The transfer of alcohol to human milk: Sensory implications and effects on
mother-infant interaction. In Alcohol and Alcoholism: Brain and Development; Spear, N.E.,
Spear, L.P., Hanningan, J.H., Goodlett, C.R., Eds.; Erlbaum: Hillsdale, NJ, USA, 1999; pp. 177–198.
75. Molina, J.C.; Domínguez, H.D.; López, M.F.; Pepino, M.Y.; Faas, A.E. The role of fetal and
infantile experience with alcohol in later recognition and acceptance patterns of the drug.
In Alcohol and Alcoholism: Brain and Development; Spear, N.E., Spear, L.P., Hanningan, J.H.,
Goodlett, C.R., Eds.; Erlbaum: Hillsdale, NJ, USA, 1999; pp. 199–228.
76. Buck, L.; Axel, R. A novel multigene family may encode odourant receptors: A molecular basis
for odour recognition. Cell 1991, 65, 175–187.
77. Menco, B.P.; Morrison, E.E. Morphology of the mammalian olfactory epithelium: Form, fine
structure, function, and pathology. In Handbook of Olfaction and Gustation; Doty, R., Ed.;
Marcel Dekker: New York, NY, USA, 2003; pp. 17–49.
78. Caterina, M.J.; Schumacher, M.A.; Tominaga, M.; Rosen, T.A.; Levine, J.D.; Julius, D. The
capsaicin receptor: A heat-activated ion channel in the pain pathway. Nature 1997, 389, 816–824.
79. Li, X.; Staszewski, L.; Xu, H.; Durick, K.; Zoller, M.; Adler, E. Human receptors for sweet and
umami taste. Proc. Natl. Acad. Sci. USA 2002, 99, 4692–4696.
80. Nelson, G.; Hoon, M.A.; Chandrashekar, J.; Zhang, Y.; Ryba, N.J.; Zuker, C.S. Mammalian
sweet taste receptors. Cell 2001, 106, 381–390.
81. Nelson, G.; Chandrashekar, J.; Hoon, M.A.; Feng, L.; Zhao, G.; Ryba, N.J.; Zuker, C.S.
An amino-acid taste receptor. Nature 2002, 416, 199–202.
82. Margolskee, R.F. Molecular mechanisms of taste transduction. Pure Appl. Chem. 2002, 74,
1125–1133.
83. Gawel, R.; van sluyter, S.; Waters, E.J. The effects of ethanol and glycerol on the body and other
sensory characteristics of Riesling wines. Aust. J. Grape Wine Res. 2007, 13, 38–45.

Beverages 2015, 1 308
84. Gawel, R. The use of language by trained and untrained experienced wine tasters. J. Sens. Stud.
1997, 12, 267–284.
85. Amerine, M.A.; Roessler, E.B. Wines: Their Sensory Evaluation; Freeman, W.H., Ed.; W. H.
Freeman & Co.: San Francisco, CA, USA, 1983.
86. Nurgel, C.; Pickering, G. Contribution of glycerol, ethanol and sugar to the perception of
viscosity and density elicited by model white wines. J. Texture Stud. 2005, 36, 303–325.
87. Guth, H.; Sies, A. Flavour of wines: Towards an understanding by reconstitution experiments
and an analysis of ethanol’s effect on odour activity of key components. In Proceedings of the
Eleventh Australian Wine Industry Technical Conference, Adelaide, Australia, 7–11 October
2001; Australian Wine Industry Technical Conference Inc.: Adelaide, Australia, 2002;
pp. 128–139.
88. Scinska, A.; Koros, E.; Habrat, B.; Kukwa, A.; Kostowski, W.; Bienkowski, P. Bitter and sweet
components of ethanol taste in humans. Drug Alcohol Depend. 2000, 60, 199–206.
89. Joshi, V.K.; Sandhu, D.K. Influence of Ethanol Concentration, Addition of Spices Extract, and
Level of Sweetness on Physico-chemical Characteristics and Sensory Quality of Apple Vermouth.
Braz. Arch. Biol. Technol. 2000, 43, 537–545.
90. Noble, A.C. Why Do Wines Taste Bitter and Feel Astringent? In Chemistry of Wine Flavour;
Waterhouse, A.L., Ebeler, S.E., Eds.; American Chemical Society: Washington, DC, USA, 1998;
pp. 156–165.
91. Conibear, H. Rising alcohol levels in wine—Is this a cause for concern? AIM Dig. 2006, 18,
1–17.
92. Pickering, G.J. Low- and Reduced-alcohol Wine: A Review. J. Wine Res. 2000, 11, 129–144.
93. Meillon, S.; Viala, D.; Medel, M.; Urbano, C.; Guillot, G.; Schlich, P. Impact of partial alcohol
reduction in Syrah wine on perceived complexity and temporality of sensations and link with
preference. Food Qual. Preference 2010, 21, 732–740.
94. Kontoudakis, N.; Esteruelas, M.; Fort, F.; Canals, J.M.; Zamora, F. Use of unripe grapes
harvested during cluster thinning as a method for reducing alcohol content and pH of wine. Aust.
J. Grape Wine Res. 2011, 17, 230–238.
95. Casassa, L.F.; Beaver, C.W.; Mireles, M.; Larsen, R.C.; Hopfer, H.; Heymann, H.; Harbertson, J.F.
Influence of Fruit Maturity, Maceration Length, and Ethanol Amount on Chemical and Sensory
Properties of Merlot Wines. Am. J. Enol. Vitic. 2013, 64, 437–449
96. Moutounet, M.; Bes, M.; Escudier, J. Las tecnologías de elaboración de vinos con bajo nivel de
etanol. Available online: http://www.acenologia.com/ciencia84.htm (accessed on 30 October 2015)
97. Massot, A.; Mietton-Peuchot, M.; Peuchot, C.; Milisic, V. Nanofiltration and reverse osmosis in
winemaking. Desalination 2008, 231, 283–289.
98. King, E.S.; Dunn, R.L.; Heymann, H. The influence of alcohol on the sensory perception of red
wines. Food Qual. Preference 2013, 28, 235–243.
99. Escudero, A.; Campo, E.; Fariña, L.; Cacho, J.; Ferreira, V. Analytical Characterization of the
Aroma of Five Premium Red Wines. Insights into the Role of Odour Families and the Concept of
Fruitiness of Wines. J. Agric. Food Chem. 2007, 55, 4501–4510.
100. Bisson, L.F. Stuck and sluggish fermentations. Am. J. Enol. Vitic. 1999, 50, 107–119.

Beverages 2015, 1 309
101. Harbertson, J.F.; Mireles, M.S.; Harwood, E.D.; Weller, K.M.; Ross, C.F. Chemical and Sensory
Effects of Saignée, Water Addition, and Extended Maceration on High Brix Must. Am. J. Enol.
Vitic. 2009, 60, 450–460.
102. Quirós, M.; Rojas, V.; Gonzalez, R.; Morales, P. Selection of non-Saccharomyces yeast strains
for reducing alcohol levels in wine by sugar respiration. Int. J. Food Microbiol. 2014, 181, 85–91.
103. Tamang, J.P.; Fleet, G.H. Yeasts diversity in fermented foods and beverages. In Yeast
Biotechnology: Diversity and Applications; Satyanarayana, T., Kunze, G., Eds.; Springer:
Dordrecht, The Netherlands, 2009; pp. 169–198.
104. Tilloy, V.; Cadiére, A.; Ehsani, M.; Dequin, S. Microbiological strategies to reduce alcohol
levels in wines. In Wine; Alcohol Level Reduction in Wine; Oenoviti International: Bordeaux,
France, 2013; pp. 29–32.
105. Kutyna, D.R.; Varela, C.; Henschke, P.A.; Chambers, P.J.; Stanley, G.A. Microbiological
approaches to lowering ethanol concentration in wine. Trends Food Sci. Technol. 2010, 21,
293–302.
106. Diban, N.; Athes, V.; Bes, M.; Souchon, I. Ethanol and aroma compounds transfer study for
partial dealcoholisation of wine using membrane contactor. J. Membrane Sci. 2008, 311,
136–146.
107. Catarino, M.; Mendes, A.; Madeira, L.M.; Ferreira, A. Alcohol removal from beer by reverse
osmosis. Sep. Sci. Technol. 2007, 42, 3011–3027.
108. Meillon, S.; Urbano, C.; Guillot, G.; Schlich, P. Acceptability of partially dealcoholized
wines—Measuring the impact of sensory and information cues on overall liking in real-life
settings. Food Qual. Preference 2010, 21, 763–773.
109. Commission Regulation (EC) No. 606/2009 of 10 July 2009. Laying Down Certain Detailed
Rules for Implementing Council Regulation (EC) No 479/2008 as Regards the Categories of
Grapevine Products, Oenological Practices and the Applicable Restrictions. Available online:
http://faolex.fao.org/docs/pdf/eur88930.pdf (accessed on 28 October 2015).
110. Commission Regulation (EU) No. 144/2013 of February 19. Amending Regulation (EC) No
606/2009 as Regards Certain Oenological Practices and the Applicable Restrictions and
Regulation (EC) No 436/2009 as Regards the Registering of These Practices in the Documents
Accompanying Consignments of Wine Products and the Wine Sector Registers to be Kept.
Available online: http://faolex.fao.org/docs/pdf/eur120800.pdf (accessed on 28 October 2015).
111. Organisation Internationale de la Vigne et du Vin (OIV). Codex Oenologique International;
Resolution OIV-ECO 433-2012; Organisation International de la Vigne et du Vin: Paris, France,
2012.
112. Organisation Internationale de la Vigne et du Vin (OIV). Codex Oenologique International;
Resolution OIV-OENO 394A-2012; Organisation International de la Vigne et du Vin: Paris,
France, 2012.
113. Gil, M.; Estévez, S.; Kontoudakis, N.; Fort, F.; Canals, J.M.; Zamora, F. Influence of partial
dealcoholization by reverse osmosis on red wine composition and sensory characteristics.
Eur. Food Res. Technol. 2013, 237, 481–488.
114. Liguori, L.; Russo, P.; Albanese, D.; di Matteo, M. Evolution of quality parameters during red
wine dealcoholization by osmotic distillation. Food Chem. 2013, 140, 68–75.

Beverages 2015, 1 310
115. King, E.S.; Heymann, H. The effect of reduced alcohol on the sensory profiles and consumer
preferences of white wine. J. Sens. Stud. 2014, 29, 33–42.
116. Lisanti, M.T.; Gambuti, A.; Piombino, P.; Pessina, R.; Moio, L. Sensory study on partial
dealcoholization of wine by osmotic distillation process. Bull. OIV 2011, 84, 95–105.
© 2015 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article
distributed under the terms and conditions of the Creative Commons Attribution license
(http://creativecommons.org/licenses/by/4.0/).