Sensory evaluation of bitterness and astringency sub-qualities of wine phenolic compounds: synergistic effect and modulation by aromas (original) (raw)
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Astringency and bitterness of selected phenolics in wine
Journal of the Science of Food and Agriculture, 1990
Trained judges rated intensities of astringency and bitterness of four phenolic substances in white wine by scalar and time-intensity methods. According to scalar rating, astringency and bitterness increased as a linear function of concentration for catechin, gallic acid, grape seed tannin and tannic acid. The polymeric tannic acid and grape seed tannin were rated more astringent than bitter; the reverse was found for their respective monomers, gallic acid and catechin. Similar results were obtained for maximum intensity ratings by time-intensity methods. As maximum intensity of astringency or bitterness increased directly with concentration, the total duration of aftertaste increased; however, little or no changes in time to maximum were observed. A slightly longer time to maximum perception for bitterness was observed than for astringency.
Food Quality and Preference, 2006
A method which can be used to estimate perceived astringency due to polyphenolic compounds is presented here. Thirty subjects were selected on the basis of them having similar salivary flows and they were trained to rate the perceived astringency of tannic acid and grape seed extract solutions. A scale of phenolic compound concentrations ranging from 0 to 3.2 g/L was selected in order to obtain an experimental curve describing the perceived intensity of the sensation. The same astringent solutions were added to a mucin solution in conditions resembling those present in the oral cavity. The formation of polyphenol-protein complexes was measured on the basis of the increasing turbidity of the reaction mixture and was expressed in terms of nephelometric turbidity units (NTU). Experimental curves describing NTU vs polyphenol concentration were obtained. Predictive models of astringency intensity vs NTU were produced. The predictive capacity of the models was checked by comparing the measured and predicted intensities of a set of samples prepared at phenolic compound concentration level varying from 0.94 to 2.13 g/L.
Journal of Sensory Studies, 1997
Two stereoisomeric phenolic compounds, (+)-cafechin and (-)-epicatechin, were rated for perceived intensity of oral astringency and bitterness by trained judges using the scalar method. Mouth drying and mouth roughening were also assessed, since they are often associated with astringency. Amounts of 375, 750 and 1500 mglL of each compound were tasted in red wine, and in a model system, similar in composition to a dry table wine. Preliminary tests showed that these concentrations were above the threshold level but within the range found in wine. A control sample (model solution or wine without the addition of the above phenolic compounds) was also evaluated. The results showed that the two compounds were both bitter and astringent. Ihe high (-)-epicatechin concentration was sign$cantly more bitter and astringent than the equal concentration of (+)-catechin in the model solution. Mouth drying and roughening ratings showed a similar increasing pattern with the ratings of astringency particularly at the higher concentrations. However, these attributes were rated diferently from astringency suggesting that although they contribute to astringency, they are not subsumed by it.
Food Quality and Preference, 2004
To simultaneously explore the primary and interactive effects of proanthocyanidin ('tannin'), ethanol, anthocyanin and wine polysaccharide concentrations on the mouth-feel perception of wine like media, a sensory study based on an incomplete factorial design was conducted. Two grape polyphenol fractions, i.e. grape seed tannins and anthocyanins, and two fractions of wine polysaccharides, (mannoproteins+arabinogalactan-proteins and rhamnogalacturonan II) were prepared and analysed. A panel of 15 trained judges generated a series of mouth-feel descriptors and rated their intensities while samples containing various levels and combinations of the components were held in mouth and after expectoration. The sensory perception was primarily determined by tannin concentration. However, the attribute ratings were also strongly influenced by all other factors both directly and through interactions. The intensities of all astringency descriptors increased with tannin concentration and were reduced when rhamnogalacturonan II was added. Bitterness increased with ethanol level and decreased in the presence of proteoglycans. Secondary effects observed included both masking and enhancement of the primary effects but also specific interaction effects. The latter are probably related to differences in the structural organization and properties of molecular assemblies involving polyphenols, polysaccharides, and ethanol.
Relationship between the Sensory-Determined Astringency and the Flavanolic Composition of Red Wines
Journal of Agricultural and Food Chemistry, 2012
The relationship between the proanthocyanidin profile and the perceived astringency was assessed in 13 commercial Tempranillo red wines. The concentration and compositional information were obtained by liquid chromatography with diode array detection coupled to electrospray ionization mass spectrometry after acid-catalyzed depolymerization of wine proanthocyanidins in the presence of excess phloroglucinol. Statistical analysis of the results showed significant correlations between sensory and chemical determinations. Astringency was more affected by the subunit composition than by the total concentration or the average degree of polymerization of wine proanthocyanidins. Higher proportions of epicatechin (EC) subunits in extension positions and gallocatechin (GC) subunits in terminal positions were shown to increase astringency. On the contrary, the amount of epigallocatechin (EGC) in both extension and terminal positions was negatively correlated with the perceived astringency.
SDRP Journal of Food Science & Technology Wine phenolics: looking for a smooth mouthfeel
Each grape variety has its own phenolic profile. However, the concentration of the phenolic compounds present in wine mainly dependson winemaking processes. Phenolic compounds influence wine sensorial characteristics namely taste or mouthfeel, bitterness, astringency and color. Humans can perceive six basic tastes: sweet, salty; sour; umami; fat-taste and bitter taste. This last basic taste is considered as a defense mechanism against the ingestion of potential poisons. Some of the genes,encoding G-protein-coupled receptors-TAS2Rs, which translate for these distinct bitter compounds detectors have been identified. Different phenolic compounds activate distinguished combination of TAS2Rs.Astringency in wine is primarily driven by proanthocyanidins, soluble protein-proanthocyanidins complexes which diminish the protective salivary film and bind to the salivary pellicle; insoluble protein-proanthocyanidins complex and proanthocyanidins are rejected against salivary film and trigger astringency sensation via increasing friction. Thus, the aim of this review is to expand the knowledge about the role of wine phenolic compounds in wine sensorial properties, namely in bitterness and astringency phenomenon's.
Journal of Sensory Studies, 2010
The aims of this work were to investigate the effect of polyphenol concentrations on astringency perception and gelatin index measurements in noncommercial red wines, as well as evaluate astringency evolution over time. Spearman coefficients showed a positive correlation between polyphenols at low concentration with gelatin index (P < 0.001), and astringency (P < 0.05). Gelatin index values and polyphenol concentrations were related by a power function at low polyphenol levels, but no correlation was shown when total polyphenol levels overcame 5.20 g/L. Similar relationships were found between perceived astringency/gelatin index, and astringency/polyphenol concentrations. It was evident that gelatin index was a better estimator of astringency when polyphenol levels were low, and astringency intensity did not increase when polyphenol concentrations were higher than 5.20 g/L. Timeintensity measurements of astringency showed that maximum intensity governed the evolution of sensation. PRACTICAL APPLICATIONS The findings from this research will aid winemakers to understand the availability of an in vitro assay to estimate the astringent sensation. This method's comparison and crossbreeding with sensory data will allow a better interpretation of what happens when wine is drunk.
Ciência e Técnica Vitivinícola, 2021
The present work was aimed at understanding the sensory responses induced by dry white wine modified with increasing concentrations of different sensory active molecules. The tasting panel was composed by 34 trained subjects characterized according to gender, smoking habits, 6-n-propylthiouracil (PROP) taster status, and sensitivity to tartaric acid, tannic acid and sucrose. Additional taste/mouthfeel responsiveness was evaluated in a basal white wine added of tartaric acid, tannic acid and sucrose. The addition of a fruity odorant mixture to the base white wine enabled the assessment of orthonasal aroma and taste intensities (sweetness, sourness, saltiness). The diversity of taste/mouthfeel responsiveness in water or wine enabled to group individuals as high or low sensitives. Likewise, the tasting panel showed two groups responding differently to aroma and flavor. Both high and low aroma sensitivity individuals showed equal (p>0.05) and congruent response to in-mouth sweet flav...
Applied Sciences
Wine polyphenols (PPhs) and volatile organic compounds (VOCs) are responsible for two of the main sensory characteristics in defining the complexity and quality of red wines: astringency and aroma. Wine VOCs’ volatility and solubility are strongly influenced by the matrix composition, including the interactions with PPhs. To date, these interactions have not been deeply studied, although the topic is of great interest in oenology. This article reviews the available knowledge on the main physicochemical and sensory effects of polyphenols on the release and perception of wine aromas in orthonasal and retronasal conditions. It describes the molecular insights and the phenomena that can modify VOCs behavior, according to the different chemical classes. It introduces the possible impact of saliva on aroma release and perception through the modulation of polyphenols–aroma compounds interactions. Limitations and possible gaps to overcome are presented together with updated approaches used ...
Taster responses to astringency in red wines
2017
Mestrado Vinifera Euromaster - Instituto Superior de Agronomia / DISAFA. Universita degli Studi di TorinoThe present work aimed to evaluate the responses of a panel tasters to astringency in red wines. The panel was trained on the tastes of the mouth in relation to the acidity, sweetness, bitterness and in particular to astringency. Twenty-one subjects were selected through identification of basic tastes and binary taste mixtures. Tasters were introduced first to the theory of astringency and extensively trained to differentiate astringency from bitterness and sourness using 3.0 g/L tannic acid, 0.25 g/L caffeine and 4 g/L tartaric acid to first in water then in white wine. Tasters were segmented according to gender, 6-n-propyltiouracil (PROP) status, saliva flow and Vinotype. The tests determined the detection and recognition thresholds of commercial seed grape tannin (CT) in white wine (0.95 g/L and 1.21 g/L, respectively). These thresholds were not related with response to PROP o...