Longer cluster hanging time decreases the impact of grapevine red blotch disease in Vitis vinifera L. Merlot across two seasons.

BACKGROUND: Grapevine red blotch virus (GRBV) is a recently discovered virus and a major concern for the wine industry. Prior research indicated that GRBV delays grape ripening by reducing °Brix and anthocyanin concentrations in grapes from infected vines, resulting in higher ethanol concentrations in wines made from healthy fruit compared to diseased vines, which have an impact on sensory properties. In this study, infected fruit (Vitis vinifera L. Merlot) was sequentially harvested (in 2016 and 2017) and chaptalized (in 2017) to ameliorate the impact of GRBV on grape and final wine composition. RESULTS: Chemical parameters including phenolic and volatile profiles of grapes and their subsequent wines were measured. Sensory properties were determined by descriptive analyses. Results demonstrated that GRBV decreased sugar accumulation and anthocyanin synthesis in grapes. Wines from GRBV grapes harvested at later ripening stage produced wines that were more similar chemically and sensorially to wines made from healthy fruit than to wines made from GRBV fruit harvested earlier. CONCLUSION: A longer hang time of GRBV grapes is a potential strategy to mitigate the impacts of GRBV. However, chaptalization of diseased fruit must was inefficient at increasing similarities to wines made from healthy fruit. © 2023 Society of Chemical Industry.

Investigation of Different Winemaking Protocols to Mitigate Smoke Taint Character in Wine.

There is an increase in the levels of volatile phenols in wine made with smoke-impacted grapes. These compounds are present in wood smoke resulting from the pyrolysis (thermal decomposition) of lignin and at high levels give overpowering smoky and ashy characters to a wine. This research aimed to compare all the suggested wine mitigation strategies that evolved from prior research using smoke-impacted grapes under identical winemaking conditions except for the parameter under investigation. Cabernet Sauvignon grapes were received from three areas with varying amounts of smoke exposure in Northern California. Gas chromatography combined with mass spectrometry (GC-MS) and descriptive analyses were performed to correlate the volatile phenol composition to smoke taint characteristics. The winemaking variables investigated were the use of different fermentation yeasts, oak additions, and fermentation temperatures. Among other attributes, smokiness and ashy aftertaste were significantly different among the wines, showing a clear difference between the wines made from smoke-impacted fruit and the control wines made from non-impacted fruit. Findings indicate that mitigation strategies during red wine fermentation have a limited impact on the extraction of smoke-taint markers and the expression of smoke-taint sensory characteristics.

Impact of Grapevine Red Blotch Disease on Cabernet Sauvignon and Merlot Wine Composition and Sensory Attributes.

Grapevine red blotch disease (GRBD) is a recently identified viral disease that affects grapevines. GRBD has been shown to impact grapevine physiology and grape composition by altering specific ripening events. However, no studies have been reported on the impact of GRBD on wine composition and its sensory attributes. This study evaluated the impact of GRBD on wine primary and secondary metabolites, in addition to its sensory properties, when making wines from Cabernet Sauvignon and Merlot grapes during two seasons. Wines made with GRBD-impacted fruit were lower in ethanol content when compared to wines made with grapes from healthy grapevines. This was attributed to the lower total soluble sugar (TSS) levels of diseased grapes due to delayed ripening at harvest. GRBD impacted wine phenolic composition by decreasing anthocyanin concentrations and increasing flavonol concentrations in some instances. Additionally, proanthocyanidin concentrations were also consistently higher in GRBD wines compared to wines made from healthy fruit. Descriptive analysis demonstrated that GRBD can impact wine style by altering aroma, flavor, and mouthfeel attributes. However, the extent of GRBD impact on wine composition and sensory properties were site and season dependent.

The impact of grapevine red blotch disease on Vitis vinifera L. Chardonnay grape and wine composition and sensory attributes over three seasons.

BACKGROUND: Grapevine red blotch virus (GRBV) is a recently discovered DNA virus, which was demonstrated to be responsible for grapevine red blotch disease (GRBD). Its presence has been confirmed in the United States, Canada, Mexico, and South Korea in white and red Vitis vinifera cultivars, including Chardonnay. It has been shown that the three-cornered alfalfa treehopper (Spissistilus festinus) was able to both acquire the GRBV from a grapevine infected and transmit it to healthy grapevines in glasshouse conditions. Studies found that GRBD impacts fruit price, grapevine physiology, and grape berry composition and metabolism in red cultivars. This study evaluated the impact of GRBD on V. vinifera L. Chardonnay grape and wine composition and sensory properties from one vineyard during the 2014, 2015 and 2016 seasons. RESULTS: Grapes from symptomatic red blotch diseased grapevines were lower in total soluble solids, flavan-3-ol, and total phenolic content, and higher in flavonol content when compared to grapes from healthy grapevines. Wines made with grapes from symptomatic grapevines resulted mostly in lower ethanol content and higher pH when compared to wines made from healthy grapevines. Analysis of volatile compounds and descriptive analysis demonstrated that GRBD can impact wine style by altering aroma, flavor, and mouthfeel attributes. CONCLUSIONS: The impacts of GRBD on grape composition directly influenced wine chemistry. The decreased ethanol content impacted not only the levels of volatile compounds but the sensory perception during descriptive analysis. The extent of GRBD impact on the grape composition and wine composition and sensory attributes varied between seasons. © 2019 Society of Chemical Industry.

Characterization of Red Wine Proanthocyanidins Using a Putative Proanthocyanidin Database, Amide Hydrophilic Interaction Liquid Chromatography (HILIC), and Time-of-Flight Mass Spectrometry.

Proanthocyanidins are complex polymers of flavan-3-ol monomers and play a key sensory and health role in foods and beverages. We describe here a novel method for characterizing wine proanthocyanidins using a theoretical database comprised of the chemical formula and exact mass of 996 compounds. The database was constructed using the four primary grape and wine proanthocyanidin monomers: (epi)catechin, (epi)catechin-3-O-gallate, (epi)gallocatechin, and (epi)gallocatechin-3-O-gallate, each combined in all possible combinations up to a polymerization of 10. The database was queried against spectra collected using ultrahigh performance liquid chromatography (UHLPC) with a hydrophilic interaction liquid chromatography (HILIC) column and coupled to a high-resolution accurate mass quadrupole time-of-flight mass spectrometer (Q-TOF MS). Two wine samples produced with different post fermentation maceration were analyzed using the presented method to demonstrate application for analysis of diverse proanthocyanidins. The first sample was pressed immediately at the end of fermentation when all sugar had been utilized and the second received eight weeks of post fermentation maceration. The HILIC column combined with high resolution tandem mass spectrometry and database matching provided tentative identification of 89 compounds with excellent resolution and without the need for two-dimensional separations. The identified compounds were visualized with Kendrick mass analysis, a simple technique allowing for rapid visualization of which compounds are present in a given sample.

Validation of a paper-disk approach to facilitate the sensory evaluation of bitterness in dairy protein hydrolysates from a newly developed food-grade fractionation system.

Casein-hydrolysates (NaCaH) are desirable functional ingredients, but their bitterness impedes usage in foods. This study sought to validate a paper-disk approach to help evaluate bitterness in NaCaHs and to develop a food-grade approach to separate a NaCaH into distinct fractions, which could be evaluated by a sensory panel. Membrane filtration generated <0.2-µm and <3-kDa permeates. Further fractionation of the <3-kDa permeate by flash-chromatography generated four fractions using ethanol (EtOH) concentrations of 5, 10, 30 and 50%. As some fractions were poorly soluble in water, the fractions were resolubilzed in EtOH and impregnated into paper-disks for sensory evaluation. Bitterness differences observed in the membrane fractions using this sensory evaluation approach reflected those observed for the same fractions presented as a liquid. The flash-chromatography fractions increased in bitterness with an increase in hydrophobicity, except for the 50% EtOH fraction which had little bitterness. Amino acid analysis of the fractions showed enrichment of different essential amino acids in both the bitter and less bitter fractions. Practical Applications: The developed food-grade fractionation system, allowed for a simple and reasonably scaled approach to separating a NaCaH, into physicochemically different fractions that could be evaluated by a sensory panel. The method of sensory evaluation used in this study, in which NaCaH samples are impregnated into paper-disks, provided potential solutions for issues such as sample insolubility and limited quantities of sample. As the impregnated paper-disk samples were dehydrated, their long storage life could also be suitable for sensory evaluations distributed by mail for large consumer studies. The research, in this study, allowed for a greater understanding of the physicochemical basis for bitterness in this NaCaH. As some essential amino acids were enriched in the less bitter fractions, selective removal of bitter fractions could allow for the incorporation of the less bitter NaCaH fractions into food products for added nutritional value, without negatively impacting sensory properties. There is potential for this approach to be applied to other food ingredients with undesirable tastes, such as polyphenols.

Developmental and Metabolic Plasticity of White-Skinned Grape Berries in Response to Botrytis cinerea during Noble Rot.

Noble rot results from exceptional infections of ripe grape (Vitis vinifera) berries by Botrytis cinerea. Unlike bunch rot, noble rot promotes favorable changes in grape berries and the accumulation of secondary metabolites that enhance wine grape composition. Noble rot-infected berries of cv Sémillon, a white-skinned variety, were collected over 3 years from a commercial vineyard at the same time that fruit were harvested for botrytized wine production. Using an integrated transcriptomics and metabolomics approach, we demonstrate that noble rot alters the metabolism of cv Sémillon berries by inducing biotic and abiotic stress responses as well as ripening processes. During noble rot, B. cinerea induced the expression of key regulators of ripening-associated pathways, some of which are distinctive to the normal ripening of red-skinned cultivars. Enhancement of phenylpropanoid metabolism, characterized by a restricted flux in white-skinned berries, was a common outcome of noble rot and red-skinned berry ripening. Transcript and metabolite analyses together with enzymatic assays determined that the biosynthesis of anthocyanins is a consistent hallmark of noble rot in cv Sémillon berries. The biosynthesis of terpenes and fatty acid aroma precursors also increased during noble rot. We finally characterized the impact of noble rot in botrytized wines. Altogether, the results of this work demonstrated that noble rot causes a major reprogramming of berry development and metabolism. This desirable interaction between a fruit and a fungus stimulates pathways otherwise inactive in white-skinned berries, leading to a greater accumulation of compounds involved in the unique flavor and aroma of botrytized wines.

Correlating wine quality indicators to chemical and sensory measurements.

Twenty-seven commercial Californian Cabernet Sauvignon wines of different quality categories were analyzed with sensory and chemical methods. Correlations between five quality proxies-points awarded during a wine competition, wine expert scores, retail price, vintage, and wine region-were correlated to sensory attributes, volatile compounds, and elemental composition. Wine quality is a multi-faceted construct, incorporating many different layers. Depending on the quality proxy studied, significant correlations between quality and attributes, volatiles and elements were found, some of them previously reported in the literature.

Predicting the composition of red wine blends using an array of multicomponent Peptide-based sensors.

Differential sensing using synthetic receptors as mimics of the mammalian senses of taste and smell is a powerful approach for the analysis of complex mixtures. Herein, we report on the effectiveness of a cross-reactive, supramolecular, peptide-based sensing array in differentiating and predicting the composition of red wine blends. Fifteen blends of Cabernet Sauvignon, Merlot and Cabernet Franc, in addition to the mono varietals, were used in this investigation. Linear Discriminant Analysis (LDA) showed a clear differentiation of blends based on tannin concentration and composition where certain mono varietals like Cabernet Sauvignon seemed to contribute less to the overall characteristics of the blend. Partial Least Squares (PLS) Regression and cross validation were used to build a predictive model for the responses of the receptors to eleven binary blends and the three mono varietals. The optimized model was later used to predict the percentage of each mono varietal in an independent test set composted of four tri-blends with a 15% average error. A partial least square regression model using the mouth-feel and taste descriptive sensory attributes of the wine blends revealed a strong correlation of the receptors to perceived astringency, which is indicative of selective binding to polyphenols in wine.

Transcriptomic analysis of the late stages of grapevine (Vitis vinifera cv. Cabernet Sauvignon) berry ripening reveals significant induction of ethylene signaling and flavor pathways in the skin.

BACKGROUND: Grapevine berry, a nonclimacteric fruit, has three developmental stages; the last one is when berry color and sugar increase. Flavors derived from terpenoid and fatty acid metabolism develop at the very end of this ripening stage. The transcriptomic response of pulp and skin of Cabernet Sauvignon berries in the late stages of ripening between 22 and 37 °Brix was assessed using whole-genome micorarrays. RESULTS: The transcript abundance of approximately 18,000 genes changed with °Brix and tissue type. There were a large number of changes in many gene ontology (GO) categories involving metabolism, signaling and abiotic stress. GO categories reflecting tissue differences were overrepresented in photosynthesis, isoprenoid metabolism and pigment biosynthesis. Detailed analysis of the interaction of the skin and pulp with °Brix revealed that there were statistically significantly higher abundances of transcripts changing with °Brix in the skin that were involved in ethylene signaling, isoprenoid and fatty acid metabolism. Many transcripts were peaking around known optimal fruit stages for flavor production. The transcript abundance of approximately two-thirds of the AP2/ERF superfamily of transcription factors changed during these developmental stages. The transcript abundance of a unique clade of ERF6-type transcription factors had the largest changes in the skin and clustered with genes involved in ethylene, senescence, and fruit flavor production including ACC oxidase, terpene synthases, and lipoxygenases. The transcript abundance of important transcription factors involved in fruit ripening was also higher in the skin. CONCLUSIONS: A detailed analysis of the transcriptome dynamics during late stages of ripening of grapevine berries revealed that these berries went through massive transcriptional changes in gene ontology categories involving chemical signaling and metabolism in both the pulp and skin, particularly in the skin. Changes in the transcript abundance of genes involved in the ethylene signaling pathway of this nonclimacteric fruit were statistically significant in the late stages of ripening when the production of transcripts for important flavor and aroma compounds were at their highest. Ethylene transcription factors known to play a role in leaf senescence also appear to play a role in fruit senescence. Ethylene may play a bigger role than previously thought in this non-climacteric fruit.

Tracing the origin of Argentine Malbec wines by sensometrics.

The study of terroir, increasingly popular in scientific circles, remains a challenging field, particularly in terms of sensory analysis. This paper summarizes our own contribution to the field-an approach for tracing the typicity of wines by sensometrics, using the Malbec variety as a case study. This large-scale research fingerprinted 81 wines from 29 parcels from highly contrasting environments (varying climate, elevation, and soils), produced under standardized conditions in three consecutive vintages. Wines were evaluated through descriptive sensory analysis (DA) by a trained panel, and sensory descriptors were associated with different size geographic scales (zones, departments, and Geographic Indications (GIs)). The application of different sensometric tools allowed us to describe the typicity of wines and discriminate each region, proposing a novel methodology for the comprehensive evaluation of terroir from a sensory viewpoint. The vintage effect was very strong at the departmental and GI level, with aroma, taste and mouthfeel descriptors varying annually. However, certain origin descriptors remained consistent, providing insight into the typicity of Malbec. Considering the extension of the experimental study performed, this methodology provides a proof of concept for understanding both terroir and vintage effects from a sensorial perspective, offering wine producers and consumers a clear message backed by scientific evidence.

Exploring American and Italian consumer preferences for Californian and Italian red wines.

BACKGROUND: To increase the market share of Californian wines in other countries, wine preferences need to be explored in potential markets. This work studied the preferences of American and Italian consumers for red wines produced in California and Italy, focusing on wines made from the same varieties in each location. Descriptive analysis and consumer preference tests were performed. RESULTS: Americans scored each of the Californian wines significantly higher in preference than the Italian wines. In contrast, the Italian consumer preference scores for many Italian and Californian wines overlapped. By external preference mapping of the American consumer segments, the ideal flavour of one cluster was closest to the Californian Zinfandel, Merlot and Syrah, which had the 'most balanced' flavour profiles. Another cluster of Italians also preferred the Californian wines. In addition, one Italian cluster was driven by a dislike of the leather, band-aid and medicinal aromas of the Italian Merlot and Refosco. CONCLUSION: The results provided information that can contribute to wine marketing research necessary for successfully exporting Californian red wines to Italy and vice versa.

Analysing conjoint data with OLS and PLS regression: a case study with wine.

BACKGROUND: This paper presents a case study with wine where two statistical methods for the analysis of rating-based conjoint analysis data were applied. Traditionally, ordinary least squares (OLS) regression is used to estimate the relative importance of the experimental factors and the part-worth utilities of factor levels. Partial least squares (PLS) regression, which is a popular tool in sensory and consumer science, can also be used for the analysis of interval-level conjoint data. RESULTS: Using conjoint analysis, purchase intentions for Californian red and white wine were obtained from a convenience sample of young US adults (n ≈ 250). OLS and PLS regression uncovered the same systematic patterns in the data: negative utility associated with more expensive wine, and positive utility associated with famous wine regions. While OLS regression provided more accessible top-line results, an advantage of PLS regression was the graphical format of results. This provided easy insight to individual differences in the importance attached to the factors driving purchase intention. CONCLUSION: OLS and PLS regression can complement each other in the analysis of interval-level conjoint data. Dual analysis can help to ensure that the right insights are drawn from the study and communicated to internal/external clients. It may also facilitate communication within project teams.

Characterization of Humulus lupulus glycosides with porous graphitic carbon and sequential high performance liquid chromatography quadrupole time-of-flight mass spectrometry and high performance liquid chromatography fractionation.

Monoterpenes contribute to the characteristic aroma of several hop varieties and may occur as nonvolatile glycosides. Upon hydrolysis, the volatile terpenes are released from the glycoside precursors. Little is known, however, about the glycoside composition of hops. Seven pentose-hexose monoterpene alcohol glycosides from dried Humulus lupulus L. cv. Citra cones were isolated using high performance liquid chromatography separation and fractionation on a reverse phase phenyl-hexyl column. Further evaluation of each isolated fraction through HPLC qTOF MS with porous graphitic carbon (PGC) showed that the seven isolated monoterpenyl glycoside fractions could be further resolved into 20 isomers. Isolation on phenyl-hexyl followed by separation on PGC was needed to distinguish each isomer present. Additionally, the hop cones were screened for potential aroma glycosides. Using the PGC column combined with a database of over 900 potential glycosides, the identification of 21 additional monoterpene-polyol, norisoprenoid, volatile phenol, and aliphatic alcohol glycosides is reported.

Characterizing the chemical and sensory profiles of traditional American meads.

The compositional and sensorial profiles of traditional American meads were determined using standard enological, volatile, and descriptive analyses. Forty-one commercial meads produced by 35 meaderies across 20 states were selected to encompass a broad product range. The meads were analyzed for ethanol content, residual sugar, pH, titratable acidity, acetic acid, and free and total sulfur dioxide. Forty-three volatile compounds (alcohols, esters, acids, terpenes, aldehydes, aromatic hydrocarbons, etc.) were tentatively identified using a nontargeted HS-SPME-GC-MS method. Ethyl octanoate, phenylethyl alcohol, ethyl decanoate, and ethyl acetate were the most relatively abundant volatile compounds across the sample set. A trained panel (n = 11) evaluated each mead using descriptive analysis and the chemical and sensory analyses were compared. Acidity, sweetness, and cloying and viscous mouthfeel sensations, and alcoholic heat were the most influential sensory attributes and were driven by titratable acidity, residual sugar, and ethanol content, respectively. Ethyl octanoate and ethyl decanoate were correlated with manure aroma, phenylethyl alcohol with yeast and green aromas, and ethyl acetate with citrus, solvent, and green olive aromas. This research further elucidates the empirical relationship between the chemical composition and sensory profiles of commercial meads. PRACTICAL APPLICATION: This work provides the mead industry with further understanding of the compositional drivers of the sensory profiles of commercial meads and demonstrates product categories (dry, semi-sweet, sweet) do not necessarily indicate compositional or sensory attributes.

The Impact of Optical Berry Sorting on Red Wine Composition and Sensory Properties.

The impact of optical berry sorting was investigated using Grenache, Barbera, and Cabernet Sauvignon grapes from Yolo County, California in 2016. Optical sorting parameters were adjusted to remove underripe berries and material other than grapes using color parameters. Wines were made from three treatments, control (no sorting), sort (accepted material), and reject (material rejected by the optical sorter). The rate of rejection was approximately 14.9%, 3.9%, and 1.5% (w/w) for Grenache, Barbera, and Cabernet Sauvignon, respectively. Chemical composition in the finished wines was analyzed by the Adams-Harbertson assay and reversed-phase high-performance liquid chromatography for phenolics, and head-space solid-phase microextraction gas chromatography mass spectrometry for aroma profiling. In general, optical sorting was successful in removing underripe berries and material other than grapes as evidenced by lower ethanol levels and higher concentrations of total phenolics and tannin (due to the inclusion of material other than grapes) in wine made from rejected material. Despite this, no difference in final ethanol content and minimal differences in phenolic composition were observed between control and sort treatment wines for the three varieties studied. Differences were observed in the aroma profiles of the reject treatments for all three varieties compared to sort and control; however, few compounds differed significantly between the sort and control treatments. Descriptive sensory analysis revealed that panelists had difficulty distinguishing aroma, taste, mouthfeel, and color parameters among wines made from different treatments for all three varieties. Thus, optical sorting had minimal impact on wine sensory properties using the varieties and vineyards studied. Optical sorting may be used to differentiate and sort for different ripeness levels using color as a primary criterion; however, the impact on the resulting wine is likely dependent on the initial variability in grape ripeness.

Investigating the impact of regionality on the sensorial and chemical aging characteristics of Pinot noir grown throughout the U.S. West coast.

The sensorial and chemical differences among Pinot noir wines from different vineyard locations were investigated. Grapes of a single Pinot noir clone were grown on twelve different vineyard sites along the U.S. West Coast. Wines from a single vintage (2015) were made using a standardized protocol and equipment. Sensorial (i.e. aroma, taste, and mouthfeel) and chemical (i.e. polyphenolic and volatile) differences were observed among these wines at two aging time points (8- and 20- months). Vineyard location (i.e. latitude and longitude) was one of the main factors describing the major differences between the wines, while other details (i.e. soil type (60 cm), rootstock age, soil pH, rootstock type, and vines/acres) were possibly important for defining unique aging characteristics of certain vineyards. Overall, single clone Pinot noir grapes grown in different regions but made under standardized winemaking produced wines with unique chemical and sensorial profiles, which generally persisted throughout aging.

Impact of Dry Hopping on Beer Flavor Stability.

To investigate the chemical and sensorial impact of dry hopping time on typical pale ale, a standardized beer was produced and separated into ten vessels. Nine vessels were dry hopped, and one vessel remained un-hopped as a control. Impact of dry hopping contact time was investigated over 96 h. Polyphenols and iso-α-acid t/c ratio were analyzed in both Young and Aged beer samples. Total polyphenol content generally increased in both young and aged treatments compared to controls. Analysis of the t/c ratio suggests that both Young and Aged beers were chemically preserved to some degree after approximately 12 h at the given dry hopping rate regardless of age. Within the Aged beer trials, 96 h of dry hop contact yielded a significant increase in t/c ratio compared to all other Aged trials. This suggests that a 4-day dry hop regime may yield additional oxidative protection of iso-α-acids in beers stored unrefrigerated for 30 days. Descriptive analysis was also performed with an 8-person, trained panel; however, beers were sensorially distinguished by their aging time as opposed to their dry hopping time.

Evaluation of Variety, Maturity, and Farm on the Concentrations of Monoterpene Diglycosides and Hop Volatile/Nonvolatile Composition in Five Humulus lupulus Cultivars.

Pentose-hexose monoterpene alcohol glycosides were isolated and semiquantitatively measured in dried Humulus lupulus cones using UHPLC-qTOF-MS/MS and HPLC fractionation followed by GC-MS. The samples evaluated included hop cones from five important dual-purpose cultivars (varieties) in the United States, from two locations (farms) per variety and from three distinct harvest time points (maturities) per location, as dictated by dry-matter (% w/w) at the time of harvest. Hop variety accounted for the biggest variation among the concentrations of pentose-hexose monoterpene alcohol glycosides as well as other volatile and nonvolatile chemical factors measured in the samples. This indicates that genetics plays a major role in hop flavor production. Interestingly, "maturity", or ripeness at the time of harvest, was the next most significant factor impacting the concentrations of pentose-hexose monoterpene alcohol glycosides along with most of the other volatile and nonvolatile factors (such as total oil concentration and composition). However, maturity notably had a bigger impact on some cultivars such as Sabro, Mosaic, Simcoe, and Citra. Surprisingly, farm (i.e., location, farming practices, etc.) accounted for the least amount of variation among the concentrations of the different analytical factors. These results highlight the importance of breeding/genetics as well as considering hop maturity/ripeness at the time of harvest on the production and subsequent development of analytical chemical factors associated with driving hoppy beer flavor. It is essential for future studies assessing the impact of different farming practices and locations (i.e., regionality, terroir, etc.) on the constituents in hops important for hoppy beer flavor to consider and account for the impact of hop maturity as well as genetics.

Red Wine Dryness Perception Related to Physicochemistry.

The responsibility of condensed tannins in the astringency sensation is well-known, even though the physical mechanism is unclear. The aims of the study are to go deeper into the relationships between the tannin structure and red wine dryness as well as evaluate the influence of the wine matrix and tannin concentration on the interaction with proteins and dryness perception. Condensed tannins were extracted from two red wines (cv. Cabernet Sauvignon and Pinot Noir) and added back to them and to a model wine at 0.5 g/L, prior to chemical characterization of their composition by reversed-phase high-performance liquid chromatography as well as their viscosity. The physical consequences of interactions between mucin, poly-l-proline, saliva, and wines were evaluated by turbidimetry. Descriptive analysis and time-intensity evaluations of dryness were carried out by a trained panel on all wines and model solutions. The mean degree of polymerization of Cabernet Sauvignon wine with or without tannins added was higher than that of Pinot Noir wine conditions. The turbidity of saliva and poly-l-proline with tannins added to Cabernet Sauvignon was higher than of tannins added to Pinot Noir wine. Cabernet Sauvignon wines were perceived dryer than Pinot Noir by panelists, and the dryness intensity of Cabernet Sauvignon wine conditions last longer than that of Pinot Noir or model wine conditions. The dryness of red wines was related to larger tannins, higher tannin concentration, and a greater turbidity with saliva. The dryness was not affected by the addition of tannins into wine probably as a result of the aroma/taste suppression effects and the presence of other components.