1,721,109 research outputs found
Free and hydrolytically released volatile compounds of Vitis vinifera L. cv. Fiano grapes as odour-active constituents of Fiano wine
No full textGrape-derived volatile compounds, including those released from odourless glycosidic precursor present in the grape, are strongly associated with the varietal aroma characteristic of non-aromatic wines. In this study, free and glycosidically bound volatile compounds of Fiano grapes have been identified and quantified by means of gas chromatography-mass spectrometry (GC-MS). The free volatile fraction of Fiano grapes was mainly characterised by the occurrence of several aliphatic alcohols, with minor amounts of the monoterpenes linalool and geraniol, and traces of the norisoprenoid β-damascenone. The volatile fraction obtained from either enzymatic or acid hydrolysis of juice glycosides was more complex, and contained compounds belonging to the chemical classes of terpenes, norisoprenoids, benzenoids, and aliphatic alcohols. Linalool, geraniol, teprinen-4-ol, 1,1,6-trimethyl-1,2-dihydronaphtalene (TDN), β-damascenone, (E)-1-(2,3,6-trimenthylphenyl)buta-1,3-diene (TPB), ethyl cinnamate, and 4-vinyl guaiacol were detected by GC-olfactometry (GC-O) as odorants of young Fiano wine that were formed through hydrolysis of grape precursors. Pathways of formation of these compounds during winemaking were investigated. Yeast-driven enzymatic hydrolysis of glycosides was the major route for linalool and geraniol formation, while acid hydrolysis led to the formation of terpinen-4-ol, TDN, β-damascenone, TPB, and ethyl cinnamate. © 2008 Elsevier B.V. All rights reserved
Influence of yeast strain on odor-active compounds in fiano wine
Full text linkThe type of yeast strain used for wine alcoholic fermentation dramatically affects its final volatile composition and, therefore, its sensory properties. In this study, the influence of four oenological Saccharomyces strains (three S. cerevisiae and one S. bayanus) on wine volatile composition was determined on the Fiano variety, a typical cultivar from the Campania region (Italy), fermented in oak barrique. Fiano wines were analyzed by means of gas chromatography/mass spectrometry (GC/MS) and gas chromatography/olfactometry (GC/O). The results showed that the four selected yeast strains had a significant impact on the majority of volatile compounds as shown by the concentration of volatile compounds and based on the Aroma Extract Dilution Analysis (AEDA) values for many of the odor volatile compounds. This resulted in a dramatic change of the odor impact of the wines, such as the “fruity” attribute, which was higher compared to the control, and caused some changes of other odor attributes, particularly “floral”, “phenolic” and “honey”. This research demonstrates the potential of using these selected yeast strains and this technological approach of oak fermentation for this typical white wine grape variety
Aging of Aglianico and Sangiovese wine on mannoproteins: Effect on astringency and colour
No full textDuring the last years different commercial preparations based on yeast derivatives have been used in order to replace traditional ageing on lees. Three commercial mannoproteins (MP; MF; MS) were tested in Aglianico and Sangiovese red wine during one year of aging to evaluate the influence on astringency characteristics (astringency intensity and 16 subqualities), colour parameters (CIE L*a*b* coordinates, total anthocyanins, pigmented polymers) and reactive phenolic compounds (BSA-reactive tannins, saliva-reactive tannins, vanillin reactive flavans) after 3, 6 and 12 months. The taste, odor and aroma profiles completed the sensory evaluation of one-year aged wines. The effect of commercial mannoproteins on studied parameters depended on wine variety and aging period. As regard wine colour evolution, the formation of pigmented polymers was promoted from the 6th month in Aglianico by MS and MF, and in Sangiovese by all mannoproteins. Regarding wine sensory evaluation, MP reduced the astringency of Aglianico and enhanced the positive subqualities, while all mannoproteins favored spicy and balsamic notes revelation. In Sangiovese, green tannins and herbaceous notes decreased at the same time as floral notes, satin tannins and wine body augmented. Finally, the use of commercial mannoproteins improved some sensory characteristics of red wines related to positive astringency subqualities and aroma persistence
Alternative fining of Sangiovese wine: effect on phenolic substances and sensory characteristics
Full text linkBackground and Aims: In recent years, alternative fining practices have increasingly been adopted by the wine industry.The use of plant proteins, as alternatives to traditional fining agents of animal origin for clarification, meets the expectationsof a safe product. The effect of alternative fining practices was studied in Sangiovese wine.Methods and Results: Four wines of variable phenolic composition were fined with a protein of vegetable origin (patatin)and one of animal origin (gelatin) at 5 and10 g/hL, and the influence on phenolic substances (colour parameters, CIElabcoordinates, polymeric pigments, anthocyanins, flavans reactive to vanillin, tannins reactive to bovine serum albumin andsaliva) and sensory characteristics (astringency, bitterness, astringency subqualities, odour, and aroma) compared. Colourshowed that the efficiency of fining depends on: dose for high tannin wine and protein type for wines with a low concentra-tion of anthocyanins. Astringency decreased in high tannin wine and bitterness in low anthocyanin wine following fining.Fined wines resulted in improved astringency subqualities and aroma descriptors.Conclusions: The efficacy of traditional and alternative fining practices is influenced by the composition of wine phenolicsubstances.Significance of the Study: Due to the potential allergenicity of animal proteins, plant proteins represent a safe and healthyalternative to the traditional fining of Sangiovese win
Does the denomination taste better than the wine?
No full textPurpose: The purpose of this paper is twofold: first, to investigate whether consumer preferences differ for wines with diverse price points and second, to analyze the effect of denominations of origin information on preferences. Design/methodology/approach: In, total 150 regular wine buyers expressed their willingness-to-pay (WTP) for 12 red wines of 3 denominations (Chianti Classico DOCG, Morellino di Scansano DOCG and Toscana IGT) with three price points (basic=€5, medium=€10 and high=€20) in an incentive-compatible experiment, involving two consecutive rounds: a blind tasting and an informed tasting. Findings: The findings reveal that price points are not statistically related to consumer preferences measured in the blind round, while information on the denomination of origin leads to a statistically significant increase in WTP for wines of all price points for all denominations. Originality/value: This paper investigates whether Sangiovese-based wines at varying levels of price points (basic, medium and high) receive different WTP by consumers in non-hypothetical experimental auctions. Furthermore, the effect of denominations of origin information on preferences is explored, comparing evaluations without and with this specific information
Interactions between polyphenols and volatile compounds in wine: A literature review on physicochemical and sensory insights
Full text linkWine 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 in-troduces 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 to investigate those interactions and their effects, as well as future perspectives on the subject
Effect of enological tannin addition on astringency subqualities and phenolic content of red wines
Full text linkFour Italian red wine varieties (Sangiovese, Montepulciano, Barbera, Nero d'Avola) were used to investigate the effect of enological tannins on astringency characteristics and phenolic content of red wines. Wines were treated with three tannins of different origins (G = grape, E= oak, and P = exotic wood) at two concentrations (10, 20 g/hl) and aged for 1 year. Wines were evaluated for astringency and for 16 subqualities using check-all-that-apply questions. In addition, polymeric pigments, tannins, flavans, total anthocyanins, and color parameters were analyzed. Enological tannin promoted color stability by pigmented polymers formation. Astringency intensity was not enhanced, even better an improvement of mouthfeel sensations was achieved with wood-derived tannins. Multivariate analysis revealed a great influence of the variety on astringency and phenolic characteristics of wines. Therefore, the initial phenolic composition of wine seems to be the main driver of the evolution of wine during aging. Practical applications: Tannin addition is an enological practice widely widespread because of many economical benefits. The use of enological tannins during aging can contribute to color stabilization and to an improvement of astringency subqualities of wines. Training on astringency subqualities with touch standards coupled with the check-all-that-apply questions can provide an interesting way to reveal the different aspects of red wine astringency. Despite high astringency and high phenolic content, a wine may present desirable subqualities which can improve wine experience. Finally, a tailored use of enological tannins depends on wine variety
Postharvest dehydration of red grapes: impact of temperature and water-loss conditions on free and glycosylated volatile metabolites of exocarp and epicarp of Nebbiolo and Aleatico varieties
Full text linkBackground: Postharvest dehydration affects the metabolism of grapes, impacting odorous secondary metabolites and therefore the features of the corresponding passito wines - high-quality products with winemaking practices linked to specific territories and related autochthonous grape varieties. Water loss and temperature conditions are the main variables of the dehydration process. This study assessed how they impacted the patterns of free and glycosylated volatile organic compounds (VOCs) of the exocarp (pulp) and epicarp (skin) in Nebbiolo and Aleatico, a neutral and semi-aromatic red grape variety, respectively. Dehydration parameters were set in tunnel conditions, and VOCs were quantitatively analyzed by solid phase extraction-gas chromatography-mass spectrometry. Results: For Nebbiolo grapes, weight loss had a greater impact on free volatiles than dehydration temperature, with a 20% weight loss increasing total VOCs in both exocarp and epicarp. Low temperature (10 °C) significantly increased (P < 0.05) the glycosylated VOCs' terpene content. In Aleatico grapes, weight loss was key in modulating free volatiles, with 30% weight loss and 15 °C leading to significant increases in VOCs, especially exocarp terpenes, acids and benzenoids. More stressful dehydration (30% weight loss at 25 °C) resulted in higher aroma precursor concentrations. Conclusion: These findings can assist passito wine production in preserving varietal aromas of original grapes trough optimized dehydration conditions, preventing sensory homologation occurring because of strong uncontrolled dehydration. They can also promote optimization of energy consumption, thus fostering financial and environmental sustainability. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry
Le variabili enologiche critiche per il miglioramento della qualità aromatica di vini ottenuti da uve bianche autoctone dell’Italia meridionale.
No full textImprovement and validation of a method for determining low molecular-weight phenols in grape skins.
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