Astringency and bitterness are organoleptic properties widely linked to tannin compounds. Due to their significance to food chemistry, the food industry, and to human nutrition and health, these ...tannins' taste properties have been a line of worldwide research. In recent years, significant advances have been made in understanding the molecular perception of astringency pointing to the contribution of different oral key players. Regarding bitterness, several polyphenols have been identified has new agonists of these receptors. This review summarizes the last data about the knowledge of these taste properties perceived by tannins. Ultimately, tannins' astringency and bitterness are hand-in-hand taste properties, and future studies should be adapted to understand how the proper perception of one taste could affect the perception of the other one.
Polyphenols have been the subject of numerous research over the past years, being referred as the nutraceuticals of modern life. The healthy properties of these compounds have been associated to a ...natural chemoprevention of 21st century major diseases such as cancer and neurodegenerative diseases (e.g. Parkinson's and Alzheimer's). This association led to an increased consumption of foodstuffs rich in these compounds such as red wine. Related to the ingestion of polyphenols are the herein revised sensorial properties (astringency and bitterness) which are not still pleasant. This review intends to be an outline both at a sensory as a molecular level of the mechanisms underlying astringency and bitterness of polyphenols. Up-to-date knowledge of this matter is discussed in detail.
Phenolic compounds (PC) are linked to astringency sensation. Astringency studies typically use simple models, with pure PC and/or proteins, far from what is likely to occur in the oral cavity. ...Different oral models have been developed here, comprising different oral epithelia (buccal mucosa (TR146) and tongue (HSC-3)) and other main oral constituents (human saliva and mucosal pellicle). These models, were used to study the interaction with two PC extracts, one rich in flavanols (a green tea extract) and one rich in anthocyanins (a red wine extract). It was observed that within a family of PC, the PC seem to have a similar binding to both TR146 and HSC-3 cell lines. When the oral constituents occur altogether, flavanols showed a higher interaction, driven by the salivary proteins. Conversely, anthocyanins showed a lower interaction when the oral constituents occur altogether, having a higher interaction only with oral cells. Epigallocatechin gallate, epicatechin gallate, epigallocatechin-3-O(3-O-methyl) gallate were the flavanols with the highest interaction. For the studied anthocyanins (delphinidin-3-glucoside, peonidin-3-glucoside, petunidin-3-glucoside and malvidin-3-glucoside), there was not a marked difference on their interaction ability. Overall, the results support that the different oral constituents can have a different function at different phases of food (PC) intake. These differences can be related to the perception of different astringency sub-qualities.
Wine, and particularly red wine, is a beverage with a great chemical complexity that is in continuous evolution. Chemically, wine is a hydroalcoholic solution (~78% water) that comprises a wide ...variety of chemical components, including aldehydes, esters, ketones, lipids, minerals, organic acids, phenolics, soluble proteins, sugars and vitamins. Flavonoids constitute a major group of polyphenolic compounds which are directly associated with the organoleptic and health-promoting properties of red wine. However, due to the insufficient epidemiological and in vivo evidences on this subject, the presence of a high number of variables such as human age, metabolism, the presence of alcohol, the complex wine chemistry, and the wide array of in vivo biological effects of these compounds suggest that only cautious conclusions may be drawn from studies focusing on the direct effect of wine and any specific health issue. Nevertheless, there are several reports on the health protective properties of wine phenolics for several diseases such as cardiovascular diseases, some cancers, obesity, neurodegenerative diseases, diabetes, allergies and osteoporosis. The different interactions that wine flavonoids may have with key biological targets are crucial for some of these health-promoting effects. The interaction between some wine flavonoids and some specific enzymes are one example. The way wine flavonoids may be absorbed and metabolized could interfere with their bioavailability and therefore in their health-promoting effect. Hence, some reports have focused on flavonoids absorption, metabolism, microbiota effect and overall on flavonoids bioavailability. This review summarizes some of these major issues which are directly related to the potential health-promoting effects of wine flavonoids. Reports related to flavonoids and health highlight some relevant scientific information. However, there is still a gap between the knowledge of wine flavonoids bioavailability and their health-promoting effects. More in vivo results as well as studies focused on flavonoid metabolites are still required. Moreover, it is also necessary to better understand how biological interactions (with microbiota and cells, enzymes or general biological systems) could interfere with flavonoid bioavailability.
Bitterness is a major sensory attribute of several common foods and beverages rich in polyphenol compounds. These compounds are reported as very important for health as chemopreventive compounds, but ...they are also known to taste bitter. In this work, the activation of the human bitter taste receptors, TAS2Rs, by six polyphenol compounds was analyzed. The compounds chosen are present in a wide range of plant-derived foods and beverages, namely, red wine, beer, tea, and chocolate. Pentagalloylglucose (PGG) is a hydrolyzable tannin, (−)-epicatechin is a precursor of condensed tannins, procyanidin dimer B3 and trimer C2 belong to the condensed tannins, and malvidin-3-glucoside and cyanidin-3-glucoside are anthocyanins. The results show that the different compounds activate different combinations of the ∼25 TAS2Rs. (−)-Epicatechin activated three receptors, TAS2R4, TAS2R5, and TAS2R39, whereas only two receptors, TAS2R5 and TAS2R39, responded to PGG. In contrast, malvidin-3-glucoside and procyanidin trimer stimulated only one receptor, TAS2R7 and TAS2R5, respectively. Notably, tannins are the first natural agonists found for TAS2R5 that display high potency only toward this receptor. The catechol and/or galloyl groups appear to be important structural determinants that mediate the interaction of these polyphenolic compounds with TAS2R5. Overall, the EC50 values obtained for the different compounds vary 100-fold, with the lowest values for PGG and malvidin-3-glucoside compounds, suggesting that they could be significant polyphenols responsible for the bitterness of fruits, vegetables, and derived products even if they are present in very low concentrations.
The call for health-promoting nutraceuticals and functional foods containing bioactive compounds is growing. Among the great diversity of functional phytochemicals, polyphenols and, more recently, ...bioactive peptides have stood out as functional compounds. The amount of an ingested nutrient able to reach the bloodstream and exert the biological activity is a critical factor, and is affected by several factors, such as food components and food processing. This can lead to unclaimed interactions and/or reactions between bioactive compounds, which is particularly important for these bioactive compounds, since some polyphenols are widely known for their ability to interact and/or precipitate proteins/peptides. This review focuses on this important topic, addressing how these interactions could affect molecules digestion, absorption, metabolism and (biological)function. At the end, it is evidenced that further research is needed to understand the true effect of polyphenol-bioactive peptide interactions on overall health outcomes.
Condensed tannins are a group of polyphenols that are associated with the astringency sensation, as they readily interact and precipitate salivary proteins. As this interaction is affected by ...carbohydrates, the aim of this work was to study the effect of some carbohydrates used in the food industry arabic gum (AG), pectin, and poligalacturonic acid (PGA) on the salivary proteins/grape seed procyanidins interaction. This was assessed monitoring the salivary proteins that remain soluble in the presence of condensed tannins with the addition of carbohydrates (HPLC) and analysis of the respective precipitates (SDS-PAGE). The results show that pectin was the most efficient in inhibiting protein/tannin precipitation, followed by AG and PGA. The results suggest that pectin and PGA exert their effect by formation of a ternary complex protein/polyphenol/carbohydrate, while AG competes with proteins for tannin binding (competition mechanism). The results also point out that both hydrophilic and hydrophobic interactions are important for the carbohydrate effects.
Purpose
Breath-by-breath energy expenditure during open water swimming has not yet been explored in an ecological environment. This study aimed to investigate and compare energetics and kinematics of ...5 km swimming, in both swimming pool and open water conditions.
Methods
Through four independent studies, oxygen uptake (
V
˙
O
2
) kinetics, heart rate (HR), blood lactate concentration (La
−
) and glucose level (BGL), metabolic power (
E
˙
), energy cost (
C
) and kinematics were assessed during 5 km front crawl trials in a swimming pool and open water conditions. A total of 38 competitive open water swimmers aged 16–27 years volunteered for this four part investigation: Study A (pool, ten females, 11 males), Study B (pool, four females, six males), Study C (pool case study, one female) and Study D (open water, three females, four males).
Results
In the swimming pool, swimmers started with an above average swimming speed (
v
), losing efficiency along the 5 km, despite apparent homeostasis for La
−
, BGL,
V
˙
O
2
,
E
˙
and
C
. In open water, swimmers started the 5 km with a below average
v
, increasing the stroke rate (SR) in the last 1000 m. In open water,
V
˙
O
2
kinetics parameters, HR, La
−
, BGL, respiratory exchange ratio and
C
were affected by the
v
and SR fluctuations along the 5 km.
Conclusions
Small fluctuations were observed for energetic variables in both conditions, but changes in
C
were lower in swimming pool than in open water. Coaches should adjust the training plan accordingly to the specificity of open water swimming.
The oxidation of two premium wines, Chianti Classico and Brunello di Montalcino, obtained from Sangiovese grapes in 2017 and 2018 vintages, is simulated through oxygen exposure by applying three ...consecutive saturation/consumption cycles. After each oxidation cycle, wines are analyzed for color intensity, hue, CIElab coordinates, polymeric pigments, monomeric anthocyanins, acetaldehyde, tannins, and flavans and compared to control wines. By increasing the oxygen supply, monomeric anthocyanins decrease faster in the younger wines, acetaldehyde is highly produced in the older ones, while the formation of polymeric pigments depends on the wine type. The color intensity, the yellow and blue tint increase in all wines. The effect of oxidation on main phenolic compounds is more affected by the wine age than the type. Oxidation also significantly affects wine sensory characteristics: the astringency intensity decreases, whereas the subqualities of silk and velvet increase. The percentage increase of the silky sensation is from four to sevenfold higher in young wines. The silkiness is correlated with some anthocyanins decrease malvidin 3-(6
II
-acetyl)-monoglucoside, delphinidin 3-monoglucoside, petunidin 3-monoglucoside, malvidin 3-monoglucoside; the velvet sensation with polymeric pigments formation, acetaldehyde production, and malvidin 3-(6
II
-acetyl)-monoglucoside decrease. Moreover, after oxidation, aged wines are characterized by an enhanced balsamic odor and aroma.
This article describes the study and musealization of a late prehistoric walled enclosure located at the Portuguese Upper Douro: Castelo Velho de Freixo de Numão. From the excavation started in 1989, ...to the opening of the site in 2007, and the publishing of a global interpretative perspective in 2019, there have been thirty years of numerous archaeological actions. I aim to summarize those actions discussing their nature and diversity. The main discovery in Castelo Velho was the identification of deposition contexts, assembling disparate materialities under different formal grammars. Such contexts date from the 3rd millennium, disappearing during the first half of the 2nd millennium BC. Deposition contexts, in association with other features, namely several narrow passages in the enclosure (probably used in successive opening and closing cycles) allowed interpreting the enclosure as a conditioned space hosting ceremonial practices during the 3rd millennium BC. Over this period, weren’t observed architectural and/or contextual discontinuities, suggesting that the site was occupied in the light of the same social dynamics. The main architectural elements of the enclosure remained active until the middle of the 2nd millennium BC. However, the traces of the occupations during this period are sparse and globally different from those of the 3rd millennium BC. Overall, the site was transformed into another place: an enclosed area, accessed only through a passage, connected to the Cogeces cultural world. The 2nd millennium BC enclosure was then a place with other social functions, whose cultural uniqueness still eludes us. Within the several questions to be made in the investigation of Castelo Velho, it should be stand out this one: What may have been the cause(s) of the turning point that took place between the end of the 3rd and the beginning of the 2nd millennium BC? We shall also ask: Has this change occurred at a regional level, does it mirror a social transformation of the Chalcolithic communities in the Upper Douro region?
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