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Sensory assessment of grape polyphenolic fractions: an insight on anthocyanins effect on in-mouth perceptions.

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Sensory assessment of grape polyphenolic fractions: an insight on anthocyanins effect on in-mouth perceptions.

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Grape anthocyanins are extracted from skins during maceration and are responsible for red wine color. Their contribution to in-mouth sensations is mainly related to their interactions with condensed tannins, the latter being the major responsible for wine astringency and mouthfeel related features. Recently, the influence of several classes of polyphenols, together with other relevant non-phenolic wine constituents, has been investigated in relation to their ability to modify the condensed tannins sensory perception. The aim of this study was to investigate the influence of anthocyanins extracted from grape skins, and divided into the three acylation classes, i.e. glucoside, acetylglucoside, and p-coumaroylglucoside, on in-mouth related features. A total anthocyanins extract and these fractions individually were tasted using different sensory approaches (triangle test, check-all-that apply, and descriptive analysis) and compared to polyphenols extracted from grape skins and seeds. Investigated sensations were the overall astringency and astringency sub-qualities, divided as sensation during tasting (in-mouth, particulates) and after expectoration (surface smoothness), as well as bitterness. Anthocyanin fractions were also added to skin and seed extracts and tasted as mixtures to understand if modifications of the in-mouth perception due to anthocyanins occurred. Although anthocyanin fractions showed a low sensory impact, total anthocyanins and glucoside fraction can be perceived at the concentration ranges found in of wines (400 mg/L), and they are involved in astringency intensity and in soft astringency sub-qualities, such as “velvety” and “chalky” attributes. Glucoside anthocyanin addition (400 mg/L) to skin and seed extract (1000 mg/L) modified the in-mouth perception, in particular seed extract was perceived as more astringent and characterized by harsher astringency sub-qualities, i.e. surface smoothness and particulates. In contrast, glucoside anthocyanin added to the skin extract led to lower surface smoothness, although overall astringency intensity was unchanged. These results confirm that the presence of anthocyanins can modify the perception of in-mouth sensations and interact in different extent with other polyphenols leading to the modification of astringency intensity and its sub-qualities.
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Sensory assessment of grape polyphenolic fractions:
an insight into the effects of anthocyanins on in-mouth perceptions
Maria Alessandra Paissoni1,2,3,*, Pierre Waffo-Teguo2,3, Wen Ma2,3,4, Michael Jourdes2,3, Simone Giacosa1,
Susana Río Segade1, Luca Rolle1and Pierre-Louis Teissedre2,3
1 Dipartimento di Scienze Agrarie, Forestali e Alimentari. Università degli Studi di Torino, Grugliasco, Italy
2 ISVV, EA 4577 Œnologie, 33140, Université de Bordeaux, Villenave d’Ornon, France
3 Inrae, ISVV, USC 1366 Œnologie, 33140, Villenave d’Ornon, France
4Wine School, Ningxia University, Yinchuan, Ningxia, 750021, P.R. China
*corresponding author: mariaalessandra.paissoni@unito.it
Anthocyanins are extracted from grape skins during maceration and are responsible for the red colour of wine. Their
contribution to in-mouth sensations is mainly related to their interactions with condensed tannins, which are largely
responsible for wine astringency and mouthfeel-related features. Recently, the influence of several groups of
polyphenols, together with other relevant non-phenolic wine constituents, was investigated in terms of their ability
to modify the sensory perception of condensed tannins. The aim of this study was to investigate the influence of
three acylation groups of anthocyanins (glucoside, acetylglucoside, and p-coumaroylglucoside) extracted from grape
skins on in-mouth related features. An extract of total anthocyanins and their individual fractions were tasted using
different sensory approaches (triangle test, check-all-that apply and descriptive analysis) and compared to
polyphenols extracted from grape skins and seeds. The investigated sensations were overall astringency and
astringency sub-qualities, which were divided into two groups: sensation during tasting (in-mouth, particulates) and
sensation after expectoration (surface smoothness). Bitterness was also studied. Anthocyanin fractions were added
to skin and seed extracts and tasted as mixtures to find out if anthocyanins modify in-mouth perception. Although
the anthocyanin fractions showed a low sensory impact, total anthocyanins and the glucoside fraction were
perceived at the concentration ranges found in wines (400 mg/L), and they were found to influence astringency
intensity and soft astringency sub-qualities, such as “velvety” and “chalky”. The addition of glucoside anthocyanin
(400 mg/L) to skin and seed extract (1000 mg/L) modified in-mouth perception; in particular, seed extract was
perceived as being more astringent and was characterised by harsher astringency sub-qualities (surface smoothness
and particulates). In contrast, the addition of glucoside anthocyanin to the skin extract led to lower surface
smoothness, although the intensity of overall astringency was unchanged. These results confirm that the presence of
anthocyanins can modify the perception of in-mouth sensations and interact to different extents with other
polyphenols, thus leading to the modification of the intensity of astringency and its sub-qualities.
anthocyanins, winegrapes, check-all-that-apply (CATA), descriptive analysis (DA), sensory analysis, polyphenols
A B S T R A C T
K E Y W O R D S
Received: 23 Juillet 2020
y
Accepted: 28 September 2020
y
Published: 19 November 2020
DOI:10.20870/oeno-one.2020.54.4.4142
VINE AND WINE
OPEN ACCESS JOURNAL
1059
OENO One 2020, 54, 4, 1059-1075 © 2020 International Viticulture and Enology Society - IVES
INTRODUCTION
In red wines, colour and “in-mouth” features
strongly influence the sensory perception of
quality (Peynaud, 1987; Parpinello et al., 2009,
Piombino et al., 2020). These characteristics are
mainly connected to the polyphenols extracted
from black grapes. Among them, two groups are
particularly relevant in terms of content:
antho cyanins and condensed tannins (also
generally referred to as proanthocyanidins), and
their constituting monomers, the flavan-3-ols.
Anthocyanins are responsible for the red wine
colour, whereas condensed tannins are involved
in both colour stabilisation and the “in-mouth”
characteristics of wine, such as astringency and
bitterness (Ma et al., 2014). Recently, wine
research has focused on the improvement of
colour parameters and the modification of “in
mouth features with the development of
technologies and practices aiming to improve the
initial grape phenolic content and composition,
their extraction into grape juice during
maceration, and wine ageing management
(Harrison, 2018). Nevertheless, wine tannin
concentration and properties a l o n e do n ot
represent the full “in-mouth” complexity of
wine. Wine technological parameters, such as
ethanol content, total acidity and pH influence
perception of astringency (Pickering and
Demiglio, 2008; Fontoin et al., 2008, Laguna et
al., 2017). Furthermore, in wine, other
macromolecules (e.g., polysaccharides, proteins,
and ellagitannins) derived from grape, yeasts, or
external sources (e.g., wood used in ageing) can
modulate the tannin effect or directly elicit
astringency sensations (Glabasnia and Hofmann,
2006; Fukui et al., 2002; Laguna et al., 2017).
The role of anthocyanins in particular has been
investigated to better understand how and to
what extent they can modulate in-mouth
properties (Table 1). Although they are known to
contribute to depleting the astringency of tannins
with the formation of complexes (Vidal et al.,
2004a) by the reduction of the available -OH
group interacting with salivary proteins, the
direct eliciting capacity of anthocyanins is far
from clear. Pure anthocyanins have bee n
reported to have a very “mild indistinctive taste”
(Singleton and Noble, 1976), supporting the
hypothesis that their role may only be relevant to
the pigments formed with flavan-3-ols. In
contrast, the addition of a mixture of isolated
grape anthocyanins to seed and skin extracts has
been found to increase astringency compared to
the unspiked fractions (Broussard et al., 2001).
These results have been supported by
winemaking experiments in which anthocyanins
or grape pomace were added to white grape
juices before fermentation, sh o w ing that
anthocyanins increase astringency sub-qualities
related to surface smoothness (fine grain), as
well as other “in-mouth attributes, such as
“dry”, “grippy” and perceived viscosity in final
wines (Oberholst e r et al . , 2009). These
descriptors agreed in part with the results of
previous studies, in which anthocyanins were
tasted in model wine solutions: they were found
to contribute to “fullness, as well as to
“chalkiness” and “coarseness” sensations (Vidal
et al., 2004b), and to increase dryness” and
“roughness(Vidal et al., 2004c). Anthocyanin
purification of grape skins and wines in high
quantities is still a challenge, since there are
several compounds which interfer with sensory
properties (mainly flavonol-belonging
molecules) and which are difficult to avoid in
extraction steps. In an imp r o vement in
purification, fractions of free glucoside and
p-coumaroylated anthocyanins were shown not
to differ from the unspiked model wine solution
in both the wine range (13 % v/v) and at a
reduced ethanol level (5 % v/v) (Vidal et al.,
2004a). Besides fraction composition and purity,
such different results from sensory analyses may
be due to the variability of the sensory technique
used (e.g., different descriptors, reference
standards and matrix solutions), as well as to
differences in assessor training (Gawel, 1997;
Gibbins and Carpenter, 2013; Sáenz-Navajas et al.,
2016)
Another possible option for evaluating the
sensorial impact of polyphenols is the
instrumental analysis of astringency and
bitterness (Table 1). Astringency is a complex
sensation involving several mechanisms, from
sensory active molecules interacting with
differe n t sal i v ary pr otein families to the
formation of soluble and precipitable complexes.
The onset of astringency involves hydrogen
bonds, as well as hydrophobic and electrostatic
interactions between sensory active molecules
and proteins, and their complexity increases in
mixed polyphenol solutions (Soares et al., 2019).
Moreover, additional phenomena can occur, such
as the direct activation of mechanoreceptors, or
direct interaction with the mouth epithelium
(Gibbins and Carpenter, 2013; Soares et al.,
2016). R ecently, the inv o l vement o f
anthocyanins in the onset and formation of
Maria Alessandra Paissoni et al.
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© 2020 International Viticulture and Enology Society - IVESOENO One 2020, 54, 4, 1059-1075 1061
TABLE 1. Studies which have carried out sensory and instrumental analyses on anthocyanin sensory properties.
Year Astringency Bitterness Mouthfeel
Notes References
1976
"indistinct mild taste" Singleton and Noble (1976)
2001 + = -
Anthocyanin extract added to seed and skin tannins in white wine Brossaud et al. (2001)
2004 + dryness, roughness, chalkiness
Anthocyanin extract (0.5 g/L, purity 78 %) added to model wine at 13 % ethanol Vidal et al. (2004c)
2004 + = fullness, chalkiness, coarseness
Anthocyanin extract (0.5 g/L, purity 70 %) added to model wine at 11, 13, and 15 % ethanol Vidal et al. (2004b)
in-mouth dryness
Anthocyanin glucosides (0.5 g/L, purity 98 %) and coumaroylated (0.5 g/L, purity 87 %) in model
wine at 13 % ethanol
= -
Anthocyanin glucosides and coumaroylated (0.5 g/L) in un-buffered, 5 % ethanol solution
2009 + = fine grain, dryness, grippiness, viscosity
Anthocyanin extracts (purity 95 %) added at 1.44 g/L in white juice during winemaking Oberholster et al. (2009)
2014 + +
Two p-coumaroylated anthocyanin contributors of bitterness, p-coumaroylated petunidin and
malvidin-3-O-gucoside contributors to astringency
Gonzalo-Diago et al. (2014)
2015 +
Glucoside anthocyanin extract (purity 95 %), moderate velvety and astringency intensity Ferrer-Gallego et al. (2015)
2017 + + dryness, bitterness, persistency
Oligomeric anthocyanins from wine fractions redissolved in 7 % ethanol buffer Sáenz-Navajas et al. (2017)
2018 + +
Year Astringency Bitterness Interaction
Notes
2013 +
TAS2Rsb activation
Malvidin-3-O-glucoside activates TAS2R7 bitterness receptors (threshold of activation 6.0 µM),
whereas cyanidin-3-O-glucoside did not activate TAS2Rs studied
Soares et al. (2013)
2015 +
Precipitable/soluble complexes
with saliva PRPsc
Individual glucoside formed complexes with acidic PRPs. Evidence of soluble complexes between
malvidin-3-O-glucoside with Histatin and PRPs.
Ferrer-Gallego et al. (2015)
2018 + Precipitable complexes with saliva
Decrease in acetylated and coumaroylated fractions when saliva was added. Precipitation occurs
depending on the anthocyanin acylation.
Paissoni et al. (2018)
2019 + Electrostatic interactions
Malvidin-3-O-glucoside and (-) epicatechin synergic interaction with PRPs. The first driven by
electrostatic interactions, the latter by hydrophobic and hydrophilic interactions. Interactions are
increased in the presence of mixture. At high concentration non-specific reactions
Soares et al. (2019)
2020 + Oral cell interactions
Anthocyanins (glucosides extract) are retained by different oral cells (HSC-3 from tongue and
TR146 from buccal mucosa). Saliva and mucosal pellicle on the cell line decreased the
anthocyanins retained.
Soares et al. (2020)
2004
Vidal et al. (2004a)
Chemical analysis
Sensory analysis
Symbols “+” and “=” indicate increased or unchanged perception respectively. a BET=Best estimated threshold, bTAS2Rs = human bitter taste receptors encoded by the TASTE 2 Receptor
(TAS2R) gene family, cPRPs = Proline-rich proteins.
complexes has been demonstrated (Ferrer-
Gallego et al., 2015; Paissoni et al. , 2018;
Soares et al., 2019). Considering bitterness,
anthocyanins have been found to activate the
corresponding taste receptors (Soares et al.,
2013). Nevertheless, testing this stimulus in an
alcoholic media is still impossible and it is
difficult to study complex polyphenol matrices,
as is the case for wine. Therefore, despite the
possibility to instrumentally study the different
mechanisms driving astringency sensations, the
final perception is influenced by the complexity
of wine polyphenols and other sensory active
molecules mixture. Therefore, together with the
instrumental evidence of anthocy a n in
involvement in astringency-driver mechanisms
and bitterness stimuli, sensory analysis is still
necessary for understanding the final in-mouth
features of solutions.
The aim of this study was to investigate the
sensory properties of grape extracts, with a
particular focus on grape anthocyanins. First,
grape extracts were tasted to establish their
sensory active thresholds, and the appropriate
terminology was selected in order to evaluate
their contribution to in-mouth sensory properties
by using a check-all-that-apply (CATA)
methodology. After that, the assessors received
training in the selected categories and
descriptors, and then carried out a descriptive
analysis (DA) of different individual grape
extracts: polyphenol extracts from skins and
seeds and anthocyanin extra c t s divided
according to acylation group. Moreover, to find
out if anthocyanins can influence the in-mouth
perception of wine, the anthocyanin extract and
its derived fractions were added to the
polyphenol-based extr a c ts and evaluated
following the same descript i v e sensory
procedure.
MATERIALS AND METHODS
1. Extraction and purification
of grape polyphenols
Grape samples from Vitis vinifera L. c v
Nebbiolo and Barbera were collected at maturity
in the Piedmont region (Northwestern Italy)
during the 2015 vintage. Grape skins were
peeled using a laboratory spatula and grape
seeds were manually removed. The obtained
grape material was lyophilised and then ground
in a ball grinder; the resulting powder was used
to carry out the extraction of grape polyphenol
fractions.
1.1. Anthocyanin extracts
Total anthocyanin (TA) and its derived glucoside
(GF), acetylglucoside (AF), and coumaroyl-
glucoside (CF) fractions were extracted and
purified by means of Centrifugal Partition
Chromatography (CPC) and preparative HPLC
as described in detail by Paissoni et al. (2018.
The final extract purity was 95 %, 98 %, 87 %,
and 91 % for TA, GF, AF, and CF respectively,
calculated using the area ratios of 520 nm and
280 nm by HPLC-DAD. Total anthocyanin
extracts (TA) from Barbera and Nebbiolo were
individually tasted in a preliminary evaluation
(triangle test; ISO 4120 : 1 983), wh e reas
subsequent evaluations were performed on
Barbera TA only. The fractions differentiated by
acylation were obtained from a mixture of the
two different varieties.
1.2. Total polyphenol extract
Skin and seed po l y phenol extraction was
performed as described by González-Centeno et
al. (2012) with an ASE 350 Accelerated Solvent
Extraction System (Dionex Corporation.
Sunnyvale, CA, USA). A mixture of Barbera and
Nebbiolo ground grape seeds and skins was used
to produce the polyphenol extracts. Grape skins
and seeds were separately subjected to eight
solid/liquid consecutive extractions with
acetone/water (80:20, v/v) for the solvent system
(40 mL of the corresponding solvent system).
The ASE experimental settings were reported in
Ma et al . (2016). Th e e xtract was then
evaporated under reduced pressure and
lyophilised to create crude skin and seed
extracts. The crude polyphenol extract (equal to
5 g of dried powder of skins or seeds) was
solubilised in 250 mL of water/ethanol
(95:5 , v/v) and extracted three times with
chloroform to remove the lipophilic material
(Lorrain et al., 2011). This aqueous extract was
concentrated and lyophilised to obtain a dry
powder, indicated as SkTOT and SdTOT for skin
and seed extracts respectively. The obtained
extracts were analysed via phloroglucinolysis
(Lorrain et al ., 2011). Me a n degree of
polymerisation (mDP) was 15.5 ± 0.45 and
3.7 0± 0.10 for SkTOT and SdTOT respectively.
The percentage of galloylation (G %) was
15.20 ± 0.27 for SdTOT and 2.20 ± 0.10 for
SkTOT. The percentage of prodelphinidins
(Pd %) was 34.00 ± 0.23 for SkTOT, whereas no
Maria Alessandra Paissoni et al.
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prodelphinidins were detected in SdTOT. For the
skin extract, anthocyanin content was determined
by HPLC-DAD ( P a issoni et a l ., 2018),
accounting for 130.2 ± 2.8 mg malvidin-3-O-
glucoside /g of extract, (Sigma–Aldrich, Saint
Quentin Fallavier, France). All the extracts were
lyophilised twice before sensory analysis to
ensure the absence of solvents.
2. Sensory analysis of grape extracts
2.1. General procedure
The sensory analyses were conducted in a tasting
room at the University of Bordeaux, Oenology
research unit (ISVV, France). The room fulfilled
the ISO 8589:2007 standard (sound insulation,
constantly regulated temperature).
A panel of 18 volunteer assessors from the
Oenology department at the University of
Bordeaux ( I SVV, France) t o ok part in t h e
experiment. All assessors are considered wine
experts according to the definition of Parr et al.
(2002). Never t h eless, a preliminary panel
selection process was carried out, in which the
assessors tasted standard solutions: aluminium
sulphate (AlSu; 2000 mg/L) for astringency,
quinine sulphate (Qsu; 15 mg/L) for bitterness,
tartaric acid (5 g/L) for acidity, and catechin
(1 g/L) for both astringency and bitterness (Chira
et al., 2012). In order to do this, two tests were
performed: a discrimination test (triangle test;
ISO 4120:1983) and an identification test. In the
triangle test, the assessors were asked to
recognise different samples in the series
composed of spiked water solution and water
without the stan d a rd molecules. For th e
identification test, the assessors were asked to
taste four spiked water solutions, and to identify
and describe the in-mouth sensations perceived.
Only those who recognised the sensations
elicited by the reference standards were accepted
as assessors for the experiment (16 assessors
remained in the experiment).
The assessors were informed of the purification
methodology for obtaining the fractions
conducted in the laboratory. If they chose to
continue in the experiment, they signed a consent
form. A total of nine sessions were conducted
prior to the formal evaluation, comprising three
preliminary assessments of the extracts and six
training sessions on the attribute scales of the
descriptive analysis (DA). Finally, the formal
descriptive analysis (DA) of the investigated
extracts was conducted in five sessions.
2.2. Preliminary extracts’ evaluation
2.2.1. Triangle test
Two sessions were dedicated to determining a
suitable extract concentration for the experiment.
Triangle tests (ISO 4120:1983) were conducted
taking into account the usual wine concentration
ranges and detection thresholds. Two total
anthocyanin extracts (from different grape
cultivars, Nebbiolo and Barbera TA; 250 mg/L),
glucoside fractions (GF; 300 and 400 mg/L),
acetylglucosides and coumaroylglucosides
fractions (AF and CF; 100 mg/L each), skin
polyphenol extract (SkTOT; 500 mg/L), and seed
polyphenol extracts (SdTOT; 500 and 750 mg/L)
were tasted. The selected extracts were dissolved
in model wine solutions (12.5 % v/v ethanol,
4 g/L of tartaric acid, pH 3.5), and were
randomly tasted along with the unspiked model
wine solutions. Nebbiolo vs Barbera TA extracts
were also tested to find any differences between
the two. Barbera TA vs un-spiked model wine
and Barbera TA vs Nebbiolo TA were evaluated
in duplicate (once per session) to confirm the
obtained results. Seed extract and skin extract at
500 mg/L, GF at 300 mg/L, CF and AF at
100 mg/L were evaluated in the first session;
whereas seeds extract at 750 mg/L and GF at
400 mg/L were evaluated in the second session,
with the aim of achieving higher discrimination
from the unspiked model wine. In addition to the
triangle tests, the assessors were asked to report
the descriptors that helped them identify the
correct sample.
2.2.2. Check-All-That-apply (CATA)
for the selection of descriptors
Four extracts representative of the groups under
evaluation were selected for a Check-All-That-
Apply (CATA) analysis, in order to identify the
most frequently reported attributes and the terms
which were able to best discriminate the extracts
(Varela and Ares, 2012). The selected grape
extracts were skin extract (SkTOT; 1000 mg/L),
seed extract (SdTOT; 100 0 mg / L ), total
anthocyanin ex t r act from Barbera (TA;
400 mg/L), and glucoside fraction of
anthocyanins (GF; 400 mg/L) in model wine
solution (12.5 % v/v ethanol, pH 3.5, 4 g/L of
tartaric acid). The selection of attributes was
based on the following: results previously
obtained by Paissoni e t al. (2018), the
descriptors reported in the triangle tests (only the
ones by assessors who correctly discriminated
© 2020 International Viticulture and Enology Society - IVESOENO One 2020, 54, 4, 1059-1075 1063
among samples), and bibliographic research on
the tasting of grape/wine extracts and fractions,
in particular anthocyanins (Oberholster et. al.,
2009; Gawel et al., 2000; Vidal et al., 2004a;
Vidal et al., 2004b; Vidal et al., 2004c; Sáenz-
Navajas et al., 2017). The selected attributes (23
in total) belonged to taste (sweet, bitter, salty,
acid), and the selection of astringent sub-
qualities was based on the mouth-feel wheel
terminology proposed by Gawel et al. (2000).
The introduced sub-qualities were: w e i ght
(watery, viscous, dense), texture (oily), heat
(hot), irritation (prickle, tingle), drying (dry),
and those related to astringency including
surface s m o othness (emery, silky) and
particulates (dusty, grainy, chalky), complex
terms (soft, round, mouthcoating, aggressive), a
dy namic a ttribute (adhesive), and the term
“rich”.
2.3. Descriptive analysis (DA)
2.3.1 Sensory training for descriptive analysis
(DA)
The assessor training on astringency and
bitterness scales was a slightly modified version
of that proposed by Chira et al. (2012). During
the first part (two sessions), the assessors were
familiarised with the different sensations, using a
stimuli concentration range. In the first session,
low (500 mg/L AlSu and 2.5 mg/L QSu) and
high (4000 mg/L AlSu and 30 mg/L QSu)
reference standards of astringency and bitterness
dissolved in water were evaluated. To improve
the assessorsability to distinguish bitterness
from astringency, they were provided with
solutions of the mixed stimuli and asked to score
low/high astringency or bitterness; one solution
was representative of low bitterness and high
astringency (2.5 mg/L Qs and 4000 mg/L AlSu),
and the other of high bitterness and low
astringency (30 mg/L QSu and 500 mg/L AlSu).
The assessorsscores allowed us to slightly
modify the scale used for training based on the
tasted fractions (section 2.2.2). Part of the second
session focused on the reference s t andard
solutions for astringency and bitterness in model
wine solutions (12.5 % (v/v) ethanol, pH 3.5,
4 g/L of tartaric acid), by carrying out an
ord ination test of selected scales ; i.e., for
astringency (model wine, and model wine plus
1000, 2000, 4000, and 6000 mg/L AlSu) and for
bitterness (model wine, and model wine plus 2.5,
5, 10, and 20 mg/L QSu). The assessors were
also asked to distinguish in low, moderate, and
high astringency and bittern e s s in mixed
solutions (2.5, 10, 20 mg/L of QSu for bitterness;
1000, 4000, and 6000 mg/L of AlSu for
astringency).
In the second part of the training (three sessions),
the assessors were familiarised with the scales to
be used for overall astringency and bitterness,
and with the definitions of astringency sub-
qualities. The assessors discussed the definitions
of particulate (in-mouth sensation), surface
smoothness (after expectoration) and irritation.
Tactile standards were used when possible,
whereas terms that did not have standards were
agreed upon by written definition. Attribute
rating was done on an 8-poi n t scale: 0 =
Maria Alessandra Paissoni et al.
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FIGURE 1. Tasting scorecard with anchored standard references.
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TABLE 2. Descriptors, definitions, and reference standards used in descriptive analysis.
Descriptor Standard or definition Reference
Bitterness (oral) Quinine sulphate (max 20 mg/L, average 10 mg/L)
Overall astringency (oral) Aluminium sulphate (max 6 g/L, average 4 g/L)
Feeling of particulate matter brushing against the surface of the mouth through the movement of the solution
Talc: talc powder
Dusty: white flour
Sandy: grounded pepper
Grainy: white sugar
Texture felt on mouth surfaces when the different surfaces came in contact with each other (after expectoration)
Silky: silk
Velvety: velvet
Fine grain: fine cotton
Hard grain: corduroy
Sense of irritation usually associated with carbonation
Tingly (low)
Prickly (moderate)
Hot (high)
Gawel et al. (2001)
Gawel et al. (2001)
Pickering
and Demiglio (2008)
Particulate
powder (manual)
Surface smoothness
fabric (manual)
Irritation
definition
“absence”, 1 = low” and 7 = high”). “Low”
and “high” levels were anchored with the use of
reference standards for each attribute (Figure 1).
For example, for overall astringency, scores of
1,4 (corresponding to the average value) and 7
corresponded to 1000, 4000, and 6000 mg/L
AlSu respectively, whereas for bitterness, these
scores corresponded to 2.5, 10 and 20 mg/L QSu.
Fabric samples were selected to anchor the
surface smoothn ess line scale: silky (silk
fabr ic) and hard emery (corduroy) were
located along the scale at 1 an d 7 points
respectively. For the p a rticulate attribute,
“chalky” (talc powder) and grainy (white
sugar) corresponded to 1 and 7 points. For
irritation, definitions were given and placed on a
low, moderate, and high scale (defined as
“tingle, prickle, and hot” at 3, 5 and 7
respectively). The 0 score represented the model
wine solution.
A summary of definitions, standard scales and
references is provided in Table 2. During the last
training session (the sixth), the assessors took
part in a simulation of a descriptive analysis to
become familiar with the tasting procedure and
scorecard. They tasted solutions for stimuli
enhanced by the samples under evaluation; in
particular, a seed tannin extract from cv Nebbiolo
(1250 mg/L), skin tannins (1000 mg/L skin
commercial oenological tannin) and catechin and
gallic acid solutions (both 1000 mg/L). At the
end of each training session, the selected
descriptors or intensity scores for each solution
were compared in a discussion led by the panel
leader.
2.3.2. Formal DA of grape extracts
The assessors evaluated a maximum of four
extract solutions per session for a total of five
sessions, in each session one sample was
repeated to evaluate the assessor’s performance
(a maximum total of five samples per session).
Each extract solution was coded with a three-
digit r andom c o de, and black ISO
3591:1977 wine glasses were used and randomly
placed in order not to bias perception.
In each evaluation session, the assessors were
asked to assess the reference model wine
solution (0 on the scale) and the medium point of
the scale on which they were trained for overall
astri ngency and bitte rness (i.e., 4000 mg/L
aluminium sulphate and 10 mg/L quinine
sulphate for astringency a n d bitterness
respectively) to help standardise the use of the
scale before sample evaluation. Fabric samples
for surface smoothness and powdery standards
for pa rtic ulates were provided during each
session in each individual booth. The complete
scales for bitterness and overall astringency
were available in case assessors wanted to try
them again before tasting. All fractions were
served at room temperature and evaluated in
individual booths. All extracts were evaluated in
model wine (12.5 % v/v ethanol, 4 g/L tartaric
acid, pH 3.5). The final concentrations were
chosen according to the wine concentration
range and triangular tests as explained above,
which were 1000 mg/L for both SdTOT and
SkTOT, 400 mg/L for TA and GF, and 100 mg/L
for CF and AF.
The individual fractions of anthocyanins, TA,
GF, and CF, were also added to the SkTOT and
SdTOT solutions (1000 mg/L each) in the same
concentration at which they were tasted
individually (400 mg/L for TA and GF, and
100 mg/L for CF) to investigate if they could
modify the sensory properties of other
polyphenols in the wine concentration range.
To minimise f a t i gue and standard i s e the
assessment process, a tasting and rinsing
procedure was established: the assessors were
asked to (1) sip and swirl the solution in their
mouth for 5-10 s, (2) expectorate, and (3) fill out
the scorecard. After each sample, the assessors
were asked to rinse their mouth out with water,
eat a piece of unsalted cracker and rinse again
with water.
3. Data analysis
Data were analysed using R software (R Core
team, Version 3.5.0; R Studio, Version 1.1.453).
The panel performance for CATA questions was
checked using the reproducibility index (Ri), as
described by Campo et al. (2008), and calculated
on the replicate sample to check assessor
repeatability. For the CATA descriptors of
selected data, the attributes on the list were
ranked according to their citation frequency to
identify the most relevant descriptors for tasting
and to better distinguish each extract. A
Correspondence Analysis (CA) was performed
on the CATA frequencies table (descriptors in
rows and evaluated extract in columns) using
Factominer R package (Lê et al., 2008). CATA
significant attributes were assessed wit h
Cochran’s Q test (Varela and Ares, 2012). Since
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CATA was performed as a preliminary approach
to underlining attributes potentially relevant for
further investigation, the criteria for significance
was increased to p < 0.1 to avoid missing
relevant terms.
The panel performance for descriptive analysis
(DA) was evaluated using PanelCheck software
(version 1.4.2). The panel performance was
tested on the subset of replicate samples by
three-way ANOVA with replicate”, “sample
(extract), and “assessors” as factors and their
interaction. The evaluation was considered
adequate when th ere we r e no significant
differences (p> 0.05) in “assessors”*“replicates”
and “assessors”*“sample” interactions. Principal
component analysis (PCA) as Tucker-1 plots
were performed for both attributes and assessors
as described by Tomic et al., 2010. The
assessorsprojections were checked in the
loading plot for bitterness, overall astringency,
particulate, irritation and surface smoothness in
order to assess their agreement on each attribute.
Two-way ANOVA (assessors as random and
extracts as fixed factors; R package nlme,
Pinheiro et al., 2020) was used to compare DA
data from the formal sessions, and in case of
significant differences, the Tukey HSD post-hoc
test (R package multcomp, Hothorn et al., 2008)
was performed to establish differences among
extracts.
RESULTS AND DISCUSSION
1. Triangle test results
The first experiment aimed to as s e ss the
concentrations at which the fractions could be
perceived by the panel in a triangle test: the
tested concentrations and results are reported in
Table 3. The initial concentration to be tested
was 500 mg/L total polyphenols from the skin
(SkTOT) and seed (SdTOT) extracts. Although
SdTOT had already been perceived as different
by most of the panel (p < 0.05), SkTOT was not
easily recognised as being different (p > 0.05).
When the concentration of SdTOT increased to
750 mg/L, more differences were perceived
(p < 0.001). Because the polyphenol range of a
red wine can vary by up to several grams per
liter, the concentration chosen for the tasting of
these two fractions was 1000 mg/L, which
fulfilled the red wine range and allowed the
fraction to be clearly perceived by the assessors.
Concerning total anthocyanin extract (TA), two
different extracts from Viti s vin i fera L. cv
Nebbiolo and Barbera (with a different ratio of
individual anthocyanins and acylation; Paissoni
et al., 2018) were tasted at a concentration of
250 mg/L. Both the extracts were perceived as
being different to the unspiked model wine
solution (p < 0.01). Interestingly, when these two
fractions were compared (400 mg/L), they were
not perceived as being different. Therefore, just
one (TA from cv Barbera) was used for the
following experiments. To improve sensitivity, a
concentration of 400 mg/L was chosen, which is
in accordance with young red wine
concentrations and is similar to other sensory
assessments (Vidal et al., 2004a; 2004b; Ferrer-
Gallego et al., 2015).
Regarding the individual fractions, glucoside
anthocyanins (GF) were perceived as different at
300 mg/L (p < 0.05), but more so at 400 mg/L
(p < 0.01); thus the latter concentration was
chosen for further analysis. Acetylated (AF) and
p-coumaroylated (CF) anthocyanins were found
to differ at 100 mg/L (p < 0.01 and p < 0.05 for
AF and CF respectively). Therefore, these
concentrations were chosen after the triangle
tests, as they could be easily perceived by the
assessors, although they are very high compared
to the concentrations found in commercial
wines.
2. CATA results
Assessor performance in a wine CATA analysis
is considered to be adequate if Ri > 0.20 (Campo
et al., 2008). In our case, assessors who failed
this repeatability test were excluded from further
analysis (n = 2). The overall panel performance
(n = 10) was Ri = 0.43, which fulfilled the
repeatability requirement. Only descriptors cited
by at least 20 % of the panel were considered for
further analysis. A frequency table summarises
each descriptor individually, wh ich were
grouped into arbitrarily chosen categories based
on bibliography (Gawel et al., 2000), namely
taste, mouthfeel, astringency sub-qualities and
complexive astringency (Table 4).
The frequency table shows the most cited terms
and the most frequently used “group” to describe
the selected grape extracts. The frequencies were
also analysed in a Correspondence Analysis
(CA, Figure 2) to find out if these terms
differe n t iated the se lected fractions. A
combination of the most cited attributes and
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TABLE 3. Triangle test results for the perception of phenolic fraction additions
to the model wine solution.
Sample
Concentration
(mg/L)
Reference solution
! value (correct answer)
n = 16
Total anthocyanin extract (Nebbiolo, TA) 250 model wine
0.01 (11)a
Total anthocyanin extract (Barbera, TA) 250 model wine
0.01 (11)a
0.01 (11)b
Glucoside fraction (GF) 300 model wine
0.05 (9)a
Glucoside fraction (GF) 400 model wine
0.01 (11)b
Acetylated fraction (AF) 100 model wine
0.01 (11)a
Coumaroylated fraction (CF) 100 model wine
0.05 (10)a
Skin polyphenols (SkTOT) 500 model wine
ns (7)a
Seed polyphenols (SdTOT) 500 model wine
0.05 (10)a
Seed polyphenols (SdTOT) 750 model wine
0.001 (12)b
Total anthocyanin extract (Nebbiolo, TA) 400
total anthocyanin extract
(Barbera, TA)
ns (8)a
ns (4)b
a First session results and band second session results.
TABLE 4. Frequencies of CATA analysis.
Group
Sub-qualitiesaRank % in the group % in total p-valueb
Bitter (amer) Taste 1 46.9 13.3 0.464
Acid (acide) Taste 4 21.9 6.2 0.476
Sweet (sucré) Taste 13 7.8 2.2 0.738
Salty (salé) Taste 3 23.4 6.6 0.045
Hot (brûlant) Mouthfeel heat 4 22.2 6.2 0.651
Dry (asséchant) Mouthfeel drying 12 9.5 2.7 0.037
Tingly (piquant) Mouthfeel irritation 8 15.9 4.4 0.641
Prickly (pointu) Mouthfeel irritation 11 11.1 3.1 0.478
Oily (onctueux) Mouthfeel texture 7 17.5 4.9 0.069
Watery (acqueux) Mouthfeel weight 9 14.3 4.0 0.762
Dense (dense) Mouthfeel weight 12 9.5 2.7 1.000
Emery (rugueux) Astringency sub-qualities surface smoothness 6 24.0 5.3 0.383
Dusty (poussiéreux) Astringency sub-qualities particulate 5 26.0 5.8 0.697
Grainy (granuleux) Astringency sub-qualities particulate 12 12.0 2.7 0.242
Chalky (talc) Astringency sub-qualities particulate 8 20.0 4.4 0.742
Silky (soyeux) Astringency sub-qualities surface smoothness 918.0 4.00.040
Rich (gras) Complexive astringency 12 12.2 2.7 0.336
Adhesive (adhérant) Complexive astringency dynamic 9 18.4 4.0 0.801
Soft (doux) Complexive astringency complex 8 20.4 4.4 0.475
Mouthcoating (enrobant) Complexive astringency complex 10 16.3 3.5 0.928
Aggressive (agressif) Complexive astringency complex 2 32.7 7.1 0.071
Grouping
Frequencies of citation
Descriptor
a Sub-qualities grouping taken from Gawel et al. (2000). b p-value according to the Cochran’s Q test for descriptors in
discrimination of samples. Values in bold indicate relevant terms based on Cochran’s Q test (p < 0.1) or rank of citation (1st to 8th
most cited terms).
their ability to discriminate samples was taken
into consideration for further sensory assessment
of grape extracted fractions.
The three most frequently cited descriptors were
“bitter” (13.3 %, 1st), “aggressive” (7.1 %, 2nd),
and “salty(6.6 %, 3rd) (Table 4). Interestingly,
“bitter” was often reported, but did not allow the
samples to be differentiated (p = 0.464). In
contrast, salty and aggressive were
relevantly used for the GF and SdTOT sample
characterisation respectively, and showed better
sample differentiation (p = 0.045 and p = 0.071,
for “salty” and “aggressive” respectively). These
descriptors, together with acid” and hot
(6.2 %, 4th) can be explained in part by the model
wine solution, since tartaric acid and low pH are
in accordance with acidic traits. Additionally,
ethanol has been reported to be perceived as
bitter and to induce a hot sensation (Vidal et al.,
2004b). Likewise, phenolic compounds have
been reported as bitter markers (Gonzalo-Diago
et al., 2014; Hufnagel and Hofmann, 2008), and
they therefore are common descriptors for grape
extracts.
Terms for astringent sub-qualities accounted for
22.1 % of the total citations, the terms for
“dusty” and “emery” being the most cited with
5.8 % (5th) and 5.3 % (6th) of the total citation
frequencies. Furthermore, “chalky” and “silky”
were frequently cited (4.4 %, 8th and 4.0%, 9th
respectively; Table 4).
The CA biplot is shown in Figure 2.The two
first dimensions account for 81.0 % of the
explained variance among samples. Dimension 1
(Dim1) contributed 46.3 %, and it was mainly
described by astringency sub-quality attributes:
“silky” was negatively correlated (-0.805) and
contributed to sample discrimination (p = 0.040),
whereas “emery mainly contributed to the
positive loading (+ 0.394, p > 0.1). In general,
samples on the right side of the plot can be
considered to have harsher astringency sub-
qualities (“emery”), whereas samples plotted on
the left side evoked softer sensations (“silky”).
This is in accordance with the “aggressive
attribute, which characterised the right side of
the axis (p = 0.071), in contrast with “oily
(p = 0.069) and silky (p = 0.040), which
characterised the left side.
On the other hand, Dimension 2 (Dim2)
accounted for 34.7 % of the explained variance,
and was positively correlated with “watery” and
mouthcoating” attributes (+ 0.396 and + 0.345
respectively), and negatively correlated with
“dry” and “grainy” attributes (- 0.995, p = 0.037
and - 0.504 respectively). Nevertheless, these
attributes were not able to sign i f icantly
discriminate samples even with increased
significance criteria (p< 0.1). Moreover, the
“mouthcoating”, “watery”, “grainy”, and dry”
att ributes belong to different groups; i.e.,
complex (overall astringency), weight
(mouthfeel), parti c u late (astringency sub-
qualities), and drying (mouthfeel) respectively.
Despite the variability of the group and the low
discrimination ability (p> 0.1), the descriptors
reported in the upper quadrant are linked by a
general softer sensation with respect to those
located in the lower quadrants of the plot.
According to the plot description, Sk-TOT is
related to harsher sensations, such as “grainy”
and dry, whereas SdTOT corresponds to
“aggressive” and “emery” attributes.
Regarding anthocyanin-based fractions, TA and
GF are in the upper part of the plot, and are
therefore r e p resented by watery and
“mouthcoating” sensations. The glucoside
fraction (GF), however, is differentiated by
softer astringency sub-qualities, such as “silky”,
in contrast to total anthocyanins (TA), which are
more associated with “emery”. Interestingly,
SkTOT and GF were well differentiated from
SdTOT, whereas TA was slightly different from
GF and SkTOT, and more like SdTOT in the
tasted concentrations.
In terms of both frequency and discrimination
ability, the most cited term, bitt e r , was
considered relevant enough to be investigated.
Astringent sub-qualities such as surface-
smoothness and particulate were also found to
be both highly cited and able to discriminate the
samples. Therefore, they were chosen to train
assessors in using the scales. For example,
particulate was described as feelings of
particulate matter brushing against the surface of
the mouth through the mov e m ent of the
solution”, thus as in-mouth astringency;
whereas surface smoothness was defined as
texture felt on mouth surfaces when the
different surfaces came in contact with each
other”, therefore after expectoration. Reference
standards and scales were defined, slightly
modifying the scales proposed by Pickering and
Demiglio (2008), for the evaluation of oral
sensations elicited by white wine. Ove r all
astringency was chosen for the scales to
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summarise the intensity of both in-mouth and
post expectoration astringency.
Moreover, given the high citation frequency of
the term “acid” and “hot” (6.2 %, 4th) and also
“tingly and prickly” (together 7.5 %), the
panel discussed and attempted to scale these
sensations and to verbally explain them. In this
case, the Pickering and Demiglio (2008)
definition of “tingly” was once again used, and
the scale was divided into low, moderate and
high irritation.
3. DA results
Panel performance was evaluated using a PCA
approach (data not shown) to understand the
consensus in the attributes investigated and
ANOVA for the effects of assessors, extracts and
replicates and their interactions in order to assess
panel repe a t ability. Regarding c o nsensus,
assessor projections were grouped in the loading
plot for overall astringency, particulate, and
surface smoothness, showing that the panel had
agreed on the interpretation of these terms. For
irritation, however, the assessors were spread
over the loading plot, which suggests that the
assessors did not interpret this attribute in the
same way. In addition, for the terms involved,
the ANOVA test for assessors resulted in
significant differences (p< 0.05), underlining the
differences in the evaluation of these attributes
on the scale. Hence, irritation was no longer
considered in subsequent analyses, confirming
that the use of standard references should be
preferred to verbal description of terms. ANOVA
also showed that the r e was a significant
assessors* -sample interaction (p< 0.05) for the
attribute bitterness. Examination of the PCA
projection indicated that two assessors rated
bitterness differently from the rest of the panel.
Accordingly, none of the scores from these two
assessors were taken into consideration for
further analysis. Therefore, the final DA panel
consisted of ten assessors.
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FIGURE 2. Correspondence Analysis (CA) of descriptors for the selected grape extracts performed on
the citation frequencies.
GF = glucoside anthocyanin fraction; TA = total anthocyanin fraction; SdTOT = seed polyphenol extract; SkTOT = skin
polyphenol extract. Ellipses represent confidence ellipses (p = 0.05).
3.1. Grape extract sensory characterisation
The result of the ANOVA test for the extract
effect (Figure 3) shows that overall astringency,
particulate, and surface smoothness were
significantly different among extracts (p= 0.003,
p= 0.001, and p= 0.002, respectively), but not
bitterness (p> 0.05). Likewise, Brossaud et al.
(2001) did not find significant differences
between total anthocyanin extract and tannins
from seeds and skins added to white wine,
whereas differences were reported in citric acid
solutions, in which seed extracts were
significantly higher than skin and anthocyanin
extracts. Our different results can be imputed to
differences in polyphenol extracts. In fact,
different content and composition of polyphenols
in skin and seed extracts can vary depending on
the grape features and the purification steps
applied. Alcohol can also enhance bitterness
(Mattes and DiMeglio, 2001), which may
conceal individual differences between fractions.
In contrast, overall astringency differed among
the fractions: SkTOT was the hi g h est in
astringency, but not significantly different from
SdTOT and TA. Anthocyanin fractions (GF, AF,
and CF) were rated lower in overall astringency,
significantly less than SkTOT, but not different
from SdTOT and TA. In previous research,
anthocyanin astringency ratings have been found
to be lower than seed or skin extracts, and
differences have been found depending on the
media in which they were tasted; i.e., model
wine at different ethanol level, citric acid
solution, and white wine (Brossaud et al., 2001;
Vidal et al., 2004b). Regarding GF, anthocyanin
glucoside has been reported to have moderate
astringency (Ferrer-Gallego et al., 2015).
Interestingly, the astringency sub-qualities,
particulate and surface smoothness, differed
among samples, and they agreed with the overall
perceived astringency results. In fact, SkTOT
was also perceived as the highest on the scale of
sub-qualities, corresponding to anchored
reference, “fine emery”, for surface smoothness,
and close to “grainy” for particulate attribute.
This could agree w ith higher mean
polymerisation (mDP) of skin tannins, which
increases both the overall astringency and the
puckery sensation in the mouth (Ma et al.,
2014). TA, GF, and CF fractions did not differ
from polyphenol extracts in particulate attribute,
although they were rated lower. Total
anthocyanins added to white juice hav e
previously been reported to result in a wine with
an increased “fine grain” attribute (Oberholster
et al., 2009). Our results seem to agree with the
CATA test, since TA rating corresponds to
“dusty” and “sandy” on the scale, referring to
the moderate particulate sensations in the mouth.
The acetylated fraction (AF) was rated the
lowest and was significantly different from
SkTOT extract, evoking a “chalky” sensation
previously reported in literature in an
anthocyanin sensory analysis (Vidal et al.,
2004a; Vidal et al., 2004b). Surface smoothness
of AF and CF was significantly lower than that
of skin polyphenol extracts (p = 0.002).
According to the scale, AF and CF were closer
to a “silky” sensation and TA and GF correspond
to a “velvety one, whereas Sk TOT
corresponded to “fine emery”. Interestingly, a
previous study (Ferrer-Gallego et al., 2015)
reported an increase in the descriptor “velvety”
in wine with added anthocyanin glucoside
© 2020 International Viticulture and Enology Society - IVESOENO One 2020, 54, 4, 1059-1075 1071
FIGURE 3. Descriptive analysis (DA) of grape extracts.
SdTOT = seed polyphenol extract; SkTOT = skin polyphenol extract; TA = total anthocyanin extract; GF = glucoside
anthocyanin fraction; AF = acetylated anthocyanin fraction; CF = p-coumaroylated anthocyanin fraction. Data are expressed as
means of assessor ratings and error bars are calculated as s/(n)1/2, where sis standard deviation and nis the number of assessors.
p-values are reported according to ANOVA, and different Latin letters indicate significant differences according to the HSD
Tukey test (p < 0.05).
(400 mg/L), which is in line with the results of
present study.
3.2. Mixed fractions sensory analysis
Anthocyanin fractions t a s ted alone were
perceived as contributing to bitterness, overall
astringency and its sub-qualities, surface
smoothness and particulate to different extents,
depending on their compositions and their
concentrations. Although these contributions had
lower ratings with respect to other phenol
fractions, it is interesting to determine whether
the sensory perceptions of polyphenol extracts
are influenced by the addition o f to tal
anthocyanin extracts (TA) and their derived
fractions GF and CF (Table 5). In previous
research, total anthocyanin extracts were found
to increase overall astringency when added to
seed or skin extracts (Brossaud et al., 2001;
Vidal et al. , 2004b), although this increase
depends on the concentration of proantho-
cyanidins (Vidal et al., 2004b). Under our
experimental conditions, when anthocyanin
fractions were added to the SkTOT extract, no
significant differences (p > 0.05) were found for
any of the investigated attributes, except for
surface smoothness, which was rated
significantly lower (p = 0.043) in the sample
with added GF. Co nversely, a signi f i cant
increase was found when GF was added to
SdTOT for the particulat e and surface
smoothness sub-qualities (p = 0.010 and
p = 0.030 respectively), as well as for overall
as tring ency (p = 0.009). Depending on the
polyphenol fraction, s u r f a c e smoothness
descriptors showed a n inverse trend when
anthocyanins were added, decreasing when
glucoside anthocyanins were added to skin
polyphenols (p < 0.05) and increasing when they
were added to seed polyphenols (p < 0.05).
Recently, Soares et al. (2019) showed that the
mixture of epicatechin and malvidin-3-glucoside
increased the interaction with salivary proline-
rich proteins when compared to epicatechin
alone, which may r esult in an increa s e d
perceived astringency, and thus justify the results
obtained here for SdTOT. Nevertheless, this
increase could be hidden in the skin polyphenol
extract, because of the lower a m ount of
monomeric flavanols usually reported in skin
with respect to seeds. The condensed tannins of
skins are conversely known to be highly
polymerised, and increased polymerisation is
positively correlated with perceived astringency
(Ma et al., 2014). In fact, condensed tannins are
the first drivers of in-mouth related sensations,
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TABLE 5. Descriptive Analysis (DA) of mixed extracts.
SdTOT = seed polyphenol extract; SkTOT = skin polyphenol extract; TA = total anthocyanin fraction; GF = glucoside
anthocyanin fraction; CF = p-coumaroylated anthocyanin fraction. Data are expressed as means of assessors rating and error bars
are calculated as s/(n)1/2, where sis standard deviation and nis the number of assessors. Sign: *, **, and ns indicate significance
at p < 0.05, 0.01, and not significant respectively, for the differences among samples according to ANOVA. Different Latin
letters indicate significant differences according to HSD Tukey test (p < 0.05).
Mixed extracts Bitterness Particulate Surface smoothness Overall astringency
SkTOT 3.6 ± 0.5 4.4 ± 0.5 4.6 ± 0.4 a 4.1 ± 0.5
SkTOT + TA 3.7 ± 0.5 4.3 ± 0.6 4.1 ± 0.5 ab 3.9 ± 0.5
SkTOT + GF 5.0 ± 0.5 5.3 ± 0.4 3.8 ± 0.3 b 5.4 ± 0.4
SkTOT + CF 4.3 ± 0.4 4.6 ± 0.5 4.0 ± 0.6 ab 4.0 ± 0.7
Sign ns ns * ns
p value 0.201 0.441 0.043 0.077
SdTOT 4.2 ± 0.5 3.5 ± 0.5 b 3.6 ± 0.6 b 3.0 ± 0.4 b
SdTOT + TA 5.2 ± 0.4 4.0 ± 0.5 ab 4.0 ± 0.4 ab 3.6 ± 0.3 ab
SdTOT + GF 3.8 ± 0.4 5.3 ± 0.5 a 5.1 ± 0.4 a 4.9 ± 0.5 a
SdTOT + CF 4.5 ± 0.6 3.3 ± 0.4 b 4.1 ± 0.4 ab 3.4 ± 0.4 b
Sign ns * * **
p value 0.177 0.010 0.030 0.009
particularly mouthfeel (Ferrero-del-Teso et al.,
2020). However, these results confirm the
involvement - even if to a different extent - of
other relevant groups of polyphenols (such as
anthocyanins) in the final oro-sensory perception
of wine, as has already been suggested by
Ferrero-del-Teso et al. (2020).
CONCLUSIONS
The role of anthocyanins in the in-mouth sensory
properties of wine has been evaluated in
previous studies with contradictory results. The
aim of the present study was to adapt common
methodology for sen s o ry analysis to the
investigation of the contribution of anthocyanins
alone and in more complex solutions, such as
mixed polyphenol extracts. The results showed
that anthocyanins extracted from grape skins are
involved in the “in-mouth” perception of model
wine solutions, although their contribution is less
relevant than other polyphenolic groups, such as
condensed tannins. At the wine level, glucoside
anthocyanins were related to sensations of
“velvety sub-qualities, whereas when mixed
with the other acylation groups (total
anthocyanin extract) they showed higher overall
astringency and harsher sub-qualities than when
alone. In particular, glucoside anthocyanins led
to a decrease in overall astringency in the
presence of skin polyphenols, whereas they
seemed to enhance the overall astringency and
related sub-qualities of seed polyphenols. This
behaviour could be relevant when explaining the
final in-mouth perceptions of wine, and thus
further studies would be required on the different
interactions of fractions with a suppression or
enhancing effects of sensory attributes.
Acknowledgements: M.A.P. would like to thank
Università Italo-Francese (Torino, Italy) for the
Vinci Grant 2017 supporting co-jointed PhD.
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... Oenological parameters, such as alcohol content, titratable acidity, pH, total phenols, total anthocyanins, and total tannin, are essential parameters for red wine quality [3,[26][27][28]. Differences in oenological parameters (alcohol content, titratable acidity, pH, total phenols, total anthocyanins, and total tannin) between the six sub-regions of Ningxia were explored by ANOVA; rarely significant differences were found (Table 1). ...
... Phenolic compounds are important indicators of the taste characteristics of wine, such as astringency, bitterness, and mouth-feel, and they are present both as monomers and oligomers [26,33]. In total, 19 phenolic compounds were quantified by standard curve. ...
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The eastern foothills of the Helan Mountains in the Ningxia region (Ningxia), is a Chinese wine-producing region, where Cabernet Sauvignon is the main grape cultivar; however, little compositional or flavor information has been reported on Ningxia wines. Oenological parameters, volatile profiles, and phenolic profiles were determined for 98 Ningxia Cabernet Sauvignon wines from the 2013–2018 vintages, as well as 16 from Bordeaux and California, for comparison. Ningxia wines were characterized by high ethanol, low acidity, and high anthocyanin contents. Multivariate analysis revealed that citronellol and 12 characteristic phenolic compounds distinguish Ningxia wines from Bordeaux and California wines. The concentrations of most phenolic compounds were highest in the 2018 Ningxia vintage and decreased with the age of the vintage. To our knowledge, this is the first extensive regionality study on red wines from the Ningxia region.
... This article is protected by copyright. All rights reserved addition, polysaccharides (Quijada-Morín et al., 2014;de Freitas and Mateus, 2012) and anthocyanins (Paissoni et al., 2020;Gonzalo-Diago et al., 2014) modulate astringency but their effect on aggregates and oral lubrication is still under research. ...
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Bitterness and astringency of grape and wine polyphenols
  • F Brossaud
  • V Cheynier
  • A C Noble
Brossaud, F., Cheynier, V., & Noble, A. C. (2001). Bitterness and astringency of grape and wine polyphenols. Australian Journal of grape and wine research, 7(1), 33-39. doi.org/10.1111/j.1755-0238.2001.tb00191.x
Aroma properties of young Spanish monovarietal white wines: A study using sorting task, list of terms and frequency of citation
  • E Campo
  • B V Do
  • V Ferreira
  • D Valentin
  • K Chira
  • M Jourdes
  • P L Teissedre
Campo, E., Do, B.V., Ferreira, V., Valentin, D. (2008). Aroma properties of young Spanish monovarietal white wines: A study using sorting task, list of terms and frequency of citation. Australian Journal of Grape and Wine Research, 14 (2008), pp. 104-115. doi.org/10.1111/j.1755-0238.2008.00010.x Chira, K., Jourdes, M., & Teissedre, P. L. (2012).
New anthocyanin-human salivary protein complexes
  • R Ferrer-Gallego
  • S Soares
  • N Mateus
  • J Rivas-Gonzalo
  • M T Escribano-Bailoń
  • V D Freitas
Ferrer-Gallego, R., Soares, S., Mateus, N., Rivas-Gonzalo, J., Escribano-Bailoń, M. T., & Freitas, V. D. (2015). New anthocyanin-human salivary protein complexes. Langmuir, 31(30), 8392-8401. doi.org/10.1021/acs.langmuir.5b01122