RESUMO
Due to allergenic concerns, only pea, potato, and wheat proteins have been approved as alternatives for replacing animal-based fining agents in wines. In pursuit of other substitutes, this work aimed to determine the fining ability of amaranth (Amaranthus caudatus L.) proteins (AP) in red wine, compared to quinoa (Chenopodium quinoa Willd.) (QP) and a commercial pea protein. Phenolic and volatile composition, as well as color characteristics, were analyzed. AP was as effective as QP at decreasing condensed tannins, with AP at 50 g/hL being the most effective treatment (25.6% reduction). QP and AP produced a minor or no statistical change in the total anthocyanins and wine color intensity. They reduced the total ester concentration, but the total alcohols remained unchanged. The outcomes of AP and QP were similar, and sometimes better than the pea proteins, thus suggesting that they could be promising options for the development of novel fining agents.
Assuntos
Amaranthus , Chenopodium quinoa , Proteínas de Plantas , Vinho , Amaranthus/química , Chenopodium quinoa/química , Proteínas de Plantas/química , Proteínas de Plantas/análise , Vinho/análise , Fenóis/química , Fenóis/análise , Extratos Vegetais/química , CorRESUMO
Astringency corresponds to the sensation of dryness and roughness that is experienced in the oral cavity in association with the interaction between salivary proteins and food polyphenols. In this study, the phenolic composition of seven varietal wines, the intensity of astringency they evoke and the physicochemical reactivity of these wines with whole human saliva were evaluated. Phenolic composition of wines was characterized by spectrophotometry and HPLC chromatography. Intensity of astringency was evaluated by trained sensory panels. Saliva from a single volunteer subject was used to assess wine-saliva interactions. To this end, binary mixtures were produced at different v/v wine/saliva ratios and each of them assayed for the ability of the salivary protein to diffuse on a cellulose membrane (diffusion test) and to remain in solution (precipitation test). Physicochemical reactivities between wine components and the protein fraction of saliva were contrasted against the astringency and the phenolic profile of each varietal wine. The study supports the view that astringency depends on physicochemical interactions between two complex matrices -wine and saliva- and not between some of their particular components.
Assuntos
Vinho , Humanos , Vinho/análise , Saliva/química , Paladar , Adstringentes/análise , Polifenóis/análise , Fenóis/análise , Proteínas e Peptídeos Salivares/análiseRESUMO
In-mouth interaction of red wine compounds with salivary proteins is a primary event allegedly responsible for eliciting the mouth-feel sensation of astringency. Those interactions have been currently associated with precipitation of salivary protein/polyphenol complexes. However, such single physicochemical evidence for interaction does not account for the complexity of astringency. This study aimed to develop a paper chromatography method to assess interactions between red wine and the salivary protein fraction using stepwise series of red wine/saliva binary mixtures from 100% wine to 100% saliva ("Alpha and Omega series"). Aliquots of each one of the mixtures were spotted on a cellulose membrane to scrutinize independently the distribution areas of wine components (naturally pink-colored) and salivary protein (stained blue in Coomassie Brilliant R-250). This double target detection revealed interactions between saliva and red wine components along most of the quantitative Alpha and Omega series, a point of equivalence corresponding to maximum interactivity for both complex reactants and a non-diffusible sub-fraction of saliva displaying the highest interactivity. The results indicate a novel way to assess quantitatively physicochemical interactions between red wines and human saliva but also provide new lights to approach the identification of molecular salivary structures involved in triggering astringency.
Assuntos
Saliva , Vinho , Humanos , Saliva/química , Vinho/análise , Polifenóis/análise , Adstringentes/análise , Adstringentes/química , Adstringentes/metabolismo , Proteínas e Peptídeos SalivaresRESUMO
The chemical mechanism of the acid cleavage of proanthocyanidins (PAs) has been known for decades but has yet to be optimized. Therefore, we optimized this process in Byrsonima crassifolia, Euterpe oleracea and Inga edulis extracts using the response surface methodology and assessed the effect of hydrochloric acid concentration (0.3−3.7 N), time (39−291 min), and temperature (56−98 °C) on the following response variables: PAs reduction, astringency reduction, antioxidant capacity/total polyphenols (TEAC/TP) ratio, and cyanidin content. The response variables were maximized when cleavage was performed with 3 N HCl at 88 °C for 165 min. Under these conditions, the mean PAs value and astringency in the three extracts decreased by 91% and 75%, respectively, the TEAC/TP ratio remained unchanged after treatment (p > 0.05), and the increase in cyanidin confirmed the occurrence of cleavage. Thus, the results suggest that acid cleavage efficiently minimizes undesirable technological PAs characteristics, expanding the industrial applications.
Assuntos
Euterpe , Proantocianidinas , Polifenóis , Euterpe/química , Antioxidantes/química , Extratos Vegetais/químicaRESUMO
Red wines are characterized by their astringency, a very important sensory attribute that affects the perceived quality of wines. Three mechanisms have been proposed to explain astringency, and two theories describe how these mechanisms work in an integrated manner to produce tactile sensations such as drying, roughening, shrinking and puckering. The factors involved include not only tannins and salivary proteins, but also anthocyanins, grape polysaccharides and mannoproteins, as well as other wine matrix components that modulate their interactions. These multifactorial interactions could be responsible for different sensory responses and therefore need to be further studied. This review presents the latest advances in astringency perception and its possible origins, with special attention on the interactions of components, their impact on oral perception and the development of astringency sub-qualities. Future research efforts should concentrate on understanding the mechanisms involved as well as on the limiting factors related to the conformation and stability of the tannin-salivary protein complexes. © 2021 Society of Chemical Industry.
Assuntos
Vinho , Antocianinas , Proteínas e Peptídeos Salivares , Taninos/análise , Vinho/análiseRESUMO
Due to the increase of the use of yeast derivatives (YDs) in winemaking to improve the technological and sensory properties in wines, in this work we evaluated the effect of the post-fermentation application of different yeast derivative products on the physical and chemical properties and astringency of red wines during two consecutive harvests. A commercial and two experimental new yeast derivatives were applied at a mediumâhigh dosage (30 g/hL). The addition of different yeast derivatives in red wine increased the concentration of different polysaccharide fractions and, therefore, the total polysaccharide content, producing a decrease in the duration of the wine astringency perception over time. The use of yeast derivatives could produce an adsorption/clarification and/or protective effect on the phenolic compounds. However, it did not produce an important modification of the colour parameters. An intensification or a lower decrease of the most volatile compound groups was produced, but it depended on the YDs and yeast strain used in fermentation and post-fermentation processes.
Assuntos
Fenóis/análise , Polissacarídeos/análise , Saccharomyces cerevisiae/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/análise , Vinho/análiseRESUMO
Phenolic compounds play a major role in the intensity and characteristics of wine astringency. However, studies involving commercial wine samples are still scarce. The aim of the present work was to study the relationship between astringency and phenolic composition of commercial Uruguayan Tannat wines using boosted regression trees (BRT), a novel predictive method. Forty commercial Tannat wines were evaluated by a trained sensory panel (9 members), who assessed their total astringency intensity using time-intensity (TI) and described their astringency sub-qualities using a check-all-that-apply (CATA) question composed of sixteen terms. The polyphenolic profiles of the wines were determined by HPLC-MS and conventional oenological parameters were also obtained. Fifty BRT models with different partitions of the data in training and test sets were built for astringency maximum intensity (Imax) and for the frequency of use of the 16 astringency sub-qualities considered in the CATA question. As predictor variables, 84 phenolic compounds and oenological parameters were considered for all BRT models. Both strong and weak predictive models were obtained for each response variable. Predictive accuracy was much higher for astringency intensity than for the frequency of mention of astringency sub-qualities. Still, the BRT models allowed to point out to some compositional variables most likely involved in wine astringency perception. Total tannin concentration (chemically determined) was the most relevant explanatory variable for sensory astringency, while flavan-3-ols were the individual phenolic compounds with the highest contribution to astringency, particularly some dimers, trimers and the sum of non-galloylated tetramers. However, the effect of these predictors differed according to the astringency sub-quality considered as response. As expected, non-linear relationships between phenolic compounds and astringency were found. These results contribute to the understanding of the influence of phenolic composition on wine astringency and stress the potential of BRT models for identifying the compounds responsible for this complex sensory characteristic.
Assuntos
Frutas/metabolismo , Fenóis/metabolismo , Análise de Regressão , Paladar , Vitis/metabolismo , Vinho/análise , Adulto , Algoritmos , Cromatografia Líquida de Alta Pressão , Feminino , Manipulação de Alimentos/métodos , Frutas/crescimento & desenvolvimento , Humanos , Concentração de Íons de Hidrogênio , Julgamento , Masculino , Pessoa de Meia-Idade , Espectrometria de Massas em Tandem , Percepção Gustatória , Uruguai , Vitis/crescimento & desenvolvimentoRESUMO
Astringency is one of the most important characteristics that define the quality of red wine, and is of particular relevance for Tannat, Uruguayan emblematic red wine variety. Astringency is a time-dependant and complex sensory characteristic, related to several sensations, or sub-qualities, that can be simultaneously perceived. The aim of the present study was to obtain a sensory characterization of the astringency of commercial Uruguayan Tannat wines. Forty samples with different characteristics in terms of vintage, price segment and aging in oak barrels were assessed by a panel of 9 trained assessors. Total astringency intensity was evaluated using time-intensity (TI), while astringency sub-qualities were described using a check-all-that-apply (CATA) question composed of sixteen terms. TI and the CATA question provided different information on the astringency of Tannat wines. Regarding global astringency, samples mainly differed in intensity-related parameters rather than in the development of astringency over time, although the variability was moderate. A wide range of sub-qualities, from silky and velvety to harsh and aggressive were used to describe the astringency of the evaluated wines. Four groups of samples with different astringency characteristics were identified, but this sorting was not related to vintage, price segment or aging in oak barrels. Further research is necessary to better understand how astringency characteristics are influenced by production variables, and to understand their relationship to consumers' and experts' perceived quality of Tannat wines.
Assuntos
Julgamento , Percepção Gustatória , Paladar , Vinho/análise , Adulto , Lista de Checagem , Feminino , Fermentação , Humanos , Concentração de Íons de Hidrogênio , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Fatores de Tempo , Uruguai , Vinho/economiaRESUMO
Commercial inactive dry-yeast based (IDYB) products have been shown to impact positively in different ways on the winemaking process, including sensory enhancement. Despite their relevance little information about physicochemical characteristics of individual IDYB products is available. This study aimed to physicochemically characterize a group of ten commercial IDYB products. Organic, protein and carbohydrate contents by spectrophotometric methods, protein diffusion on cellulose membranes and electrophoretic protein profiles were assessed. Interaction of a IDYB product (CP10) with either salivary protein or a proanthocyanidin-rich extract (binary mixtures) or with both of them (ternary mixtures) was also assessed. Marked physicochemical differences were observed among all ten products. CP10 was found to interact with seed extract and salivary protein. Also, as part of CP10-SE complexes, CP10 interacted with the salivary protein to form ternary complexes. Due to their huge diversity, physicochemical characterization of IDYB products before use in winemaking is recommended.
Assuntos
Glicoproteínas de Membrana/química , Vinho/análise , Glicoproteínas de Membrana/análise , Polissacarídeos , Proteínas/metabolismo , Saccharomyces cerevisiae/metabolismoRESUMO
BACKGROUND: The blending of wine is a common practice in winemaking to improve certain characteristics that are appreciated by consumers. The use of some cultivars may contribute phenolic compounds that modify certain characteristics in blended wines, particularly those related to mouthfeel. The aim of this work was to study the effect of Carménère, Merlot and Cabernet Franc on the phenolic composition, proanthocyanidin profile and mouthfeel characteristics of Cabernet Sauvignon blends. RESULTS: Significant differences in chemical composition were observed among the monovarietal wines. Separation using Sep-Pak C18 cartridges revealed differences in the concentration but not in the proportion of various proanthocyanidins. Blending reduced polyphenol concentration differences among the various monovarietal wines. Although no major overall differences were observed after blending the monovarietal wines, this oenological practice produced clear differences in mouthfeel characteristics in such a way that the quality of the perceived astringency was different. CONCLUSION: This study showed that the use of a particular wine variety (Cabernet Sauvignon) in a higher proportion in wine blending produced blends that were less differentiable from the monovarietal wine, owing to a suppression effect, producing an apparent standardization of the wines regarding chemical composition.