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Manejo da área foliar na qualidade da uva e características sensoriais do vinho cv.Chardonnay (Vitis vinifera L.) cultivada na Serra GaúchaRomagna, Antonio Luis January 1900 (has links)
O Estado do Rio Grande do Sul é o maior produtor nacional de uvas, vinhos e derivados. Na Serra Gaúcha se destaca o município de Bento Gonçalves como um dos maiores produtores. A cultivar Chardonnay é a principal uva entre as brancas na elaboração de vinho varietal e vinho base espumante. O manejo do dossel vegetativo dos vinhedos assume uma grande importância quando se visa favorecer a qualidade da uva e do vinho. A pesquisa pode contribuir para o aprimoramento de técnicas de produção visando essa melhoria. O objetivo deste estudo foi avaliar as características produtiva, a qualidade físico-química da uva e as características sensoriais dos vinhos da cultivar Chardonnay, sob o efeito de diferentes níveis de área foliar, em um vinhedo localizado no município de Bento Gonçalves, durante os ciclos 2014-2015 e 2015-2016. Foram avaliadas plantas de um vinhedo experimental, implantado em 2002, conduzido em sistema espaldeira a uma altitude de 533 m. Os tratamentos foram: T1 - área foliar de 0,8m² Kg-¹ de uva; T2 - área foliar de 1,0m² Kg-¹ de uva; T3 – área foliar de 1,20 m² Kg-¹ de uva; T4 –área foliar de 1,40m² Kg-¹ de uva. A colheita ocorreu na segunda quinzena de janeiro em ambas as safras. As variáveis massa do sarmento e produção planta-¹ foram avaliadas para estimar o equilíbrio entre área foliar e massa de frutos. Foram coletadas amostras de 18 Kg de uvas para microvinificação no ciclo 2014-2015 e posterior análise sensorial dos vinhos sendo realizadas por julgadores experientes. Os resultados indicaram que as plantas com área foliar de 0,8 m2Kg-1 de uva, apresentaram um melhor equilíbrio entre área foliar e produção de uva. As diferentes áreas foliares estudadas não interferiram no teor de Sólidos Solúveis no ciclo 2014-2015, bem como não interferiram na Acidez Titulável do mosto nos dois ciclos estudados. Para o aspecto acidez e corpo/estrutura foram os atributos sensoriais que melhor destacaram as diferenças entre os tratamentos. Os diferentes manejos de área foliar não interferiram na avaliação global dos vinhos. / The State of Rio Grande do Sul is the largest national producer of grapes, wines and derivatives. In the region called Serra Gaúcha, the city of Bento Gonçalves stands out as one of the largest producers. The Chardonnay cultivar is the main among the white ones in the elaboration of varietal wine and sparkling wine base. The management of the vegetative canopy of the vineyards assumes great importance when it is aimed to favor the quality of the grape and the wine. The research can contribute to the improvement of production techniques aimed to this improvement. The objective of this study was to evaluate the productive characteristics, the physical-chemical quality of the grape and the sensorial characteristics of the Chardonnay cultivar wines, under the effect of different levels of leaf area, in a vineyard located in the city of Bento Gonçalves, during the 2014- 2015 and 2015-2016 cycles. Plants of an experimental vineyard were evaluated, implemented in 2002, led on in espalier system at an altitude of 533 meters. The treatments were: T1 – leaf area of 0.8m² Kg-¹ of grape; T2 – leaf área of 1.0m² Kg-¹ of grape; T3 – leaf area of 1.20 m² Kg-¹ of grape; T4 – leaf area of 1.40m² Kg-¹ of grape. The harvest took place in the second half of January. The variables sarmentum mass and plant production-¹ were evaluated to estimate the balance between leaf area and fruit mass. Samples of 18 kg of grapes were collected for microvinification in the 2014-2015 cycle and subsequent sensorial analysis of the wines, being performed by experienced judges. The results indicated that the plants with leaf area of 0.8 m2Kg-1 of grape showed a better balance between leaf area and grape production. The different leaf areas studied did not interfere in the Soluble Solids content in the 2014-2015 cycle and did not interfere in the titratable acidity of the must in both cycles studied. For the acidity and body/structure aspects, the sensorial attributes were the ones which best highlighted the differences between the treatments. The different leaf area management did not interfere in the overall evaluation of the wines.
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Études chimique et sensorielle du vieillissement des vins de réserve de Champagne.Développement d’outils de sélection des vins de la Maison Veuve Clicquot Ponsardin / Chemical and sensorial studies of Champagne reserve wines aging. Development of selection tools for wines Veuve Clicquot Ponsardin managementLe Menn, Nicolas 23 April 2018 (has links)
Grâce à la définition sensorielle conceptuelle des vins de réserve de Champagne, nous avons pu caractériser les notes aromatiques développées lors d’un vieillissement qualitatif. L’intensité du sous-bois, truffe, fruits frais, fruits confits, tabac, grillé, torréfié, fumé, épicé, viennoiserie, miellé, beurré/lacté, fruits à coques et pétrolé a été évaluée dans 51 vins de réserve monovariétaux de chardonnay, pinot noir et meunier âgés de 1 à 28 ans. Une convergence sensorielle était soulignée et supposait des déterminants moléculaires communs du vieillissement.Par une approche moléculaire ciblée, le di-méthyl-sulfure (DMS), la tabanone, le 3-méthylbutanoate d’éthyle, 2-méthylbutanoate d’éthyle, l’acétate de butyle, le 5-méthylfurfural, le 2-acétylfuran, le 2-acétylthophène, le 2-méthylpyrazine, le 2-acéthyl-3-methylpyrazine, le 2-ethylthiazole et le thiazole ont montré des teneurs qui s’accumulaient dans les vins au cours du vieillissement.L’analyse conceptuelle du potentiel de vieillissement des vins de réserve a été décryptée afin de développer une nouvelle méthode d’analyse sensorielle illustrée permettant de l’évaluer. Les acides aminés libres et le potentiel en DMS proposaient des précurseurs en lien avec le potentiel des vins à vieillir.La méthode de fractionnement de l'extrait de 31 vins de réserve a permis, d’un point de vue sensoriel, une décomposition des notes aromatiques typiques de ces vins. L’identification de composés par GC-O et GC-MS présents dans les fractions a mis en évidence la présence du cyclotène et l’isophorone. L’analyse sensorielle des fractions a apportée de nombreuses pistes pour enrichir la liste des composés odorants du vieillissement. / The study of the conceptual sensory definition of Champagne reserve wines revealed the characterisation of the aromatic notes developed during the qualitative aging of these wines. The aromatic intensity of undergrowth, truffle, fresh fruits, jummy fruits, tobacco, toasted, roasted , smoked, spicy, pastries, honey, butter / milk, nuts and petrol notes was evaluated in 51 single-varietal reserve wines of Chardonnay, Pinot Noir and Miller aged from 1 to 28 years. A sensory convergence was highlighted, suggesting common molecular determinants of aging.A molecular study, targeting specific classes of aromatic compounds, demonstrated that levels of dimethyl sulphide, tabanone, ethyl 3-methylbutanoate, ethyl 2-methylbutanoate, butyl acetate, 5-methylfurfural, 2-acetylfuran, 2-acetylthophene, 2-methylpyrazine, 2-acetyl-3-methylpyrazine, 2-ethylthiazole and thiazole increase during aging.The conceptual analysis of the aging potential of reserve wines has been decrypted in order to develop a new illustrated sensory analysis method allowing its evaluation. The free amino acids and the potential in DMS may also be indicators of the aging potential of wines.The fractionation method of 31 Champagne reserve wines extract resulted, from a sensory point of view, in an aromatic notes decomposition, typical of these wines. The composition of the involved fractions was then studied by instrumental methods revealing the identification of two molecular markers; cyclotene and isophorone. The sensory analysis of the fractions opened up new perspectives, suggesting the existence of other compounds involved to qualitative aging of these wines.
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Influence of oxygen addition on the phenolic composition of red wineGeldenhuys, Lorraine 12 1900 (has links)
Thesis (MscAgric (Viticulture and Oenology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Tannins and colour components in red wine are important quality parameters. These factors can
be manipulated in the vineyard by grape growing techniques or in the cellar by different winemaking
practices. Grape seeds make a significant contribution to tannin concentration in wine
when compared to those from the skins and pulp. Tannins contribute to the ageing potential,
organoleptic properties and stabilisation of red wine colour. The colour of a red wine is also
influenced by malolactic fermentation, the biological process that transforms malic acid into
lactic acid which normally leads to an increase in pH. The subsequent change in pH alters the
anthocyanin equilibrium, the primary colour components in red wine. Oxygen contributes to the
polymerisation of anthocyanins over time to form more stable pigments that are less sensitive to
pH fluctuations and sulphur dioxide bleaching. Limited research has been done on the use of
oxygen after alcoholic fermentation and the impact it has on the phenolic composition of red
wines. Similarly, only a few studies have examined the impact of either the addition or removal
of seeds to the phenolic composition of a red wine in combination with oxygen addition.
Additionally, little published data seems to exist on the effect of different pHs on red wine’s
phenolic and colour development after oxygen addition.
In our results we have shown that it is possible to stabilise wine colour by adding
supplementary seeds before alcoholic fermentation. This led to an increase in colour intensity in
certain cases. Some red wines produced without seeds had significantly lower colour intensities.
This clearly suggests that catechins and proanthocyanidins are extracted from seeds and
contribute to wine colour as they combine with other pigments to stabilise wine colour.
Spectrophotometric and HPLC analyses have shown that the total phenolic content increased
with seed concentration. However, we have observed that a wine may possibly become
saturated with phenols when supplementary seeds are added. Anthocyanin concentrations
often decreased when oxygen was added, while polymeric phenols and polymeric pigments
sometimes increased.
When applying different oxygen dosages to a red wine on commercial scale with microoxygenation,
it was found that monomeric anthocyanins decreased as more oxygen was added
and this decrease in anthocyanins led to the formation of stable polymeric pigments. This
was reflected in the significant increase in colour intensity for the wines receiving oxygen. Small
differences were detected in the total phenol and tannin concentration for the control and
oxygenated wines. However, some of these phenolic and colour differences disappeared
during subsequent ageing of the wine.
When making wines of different initial pHs, we observed that the colour density decreased
as the pH increased. The application of oxygen reduced the decrease in colour during MLF,
especially at a lower pH. The addition of oxygen did not result in significantly different polymeric
pigment concentrations in the various pH treatments, although the results could have been
different if the wines were aged. However, pH differences in the range between 3.4 and 4.0 did
not significantly influence the phenol composition of the wines under our conditions. This study
led to a better understanding on the effect of oxygen additions under different conditions on red
wine's phenolic and colour composition. / AFRIKAANSE OPSOMMING: Tanniene en kleur komponente teenwoordig in rooiwyn is belangrike kwaliteit parameters.
Hierdie faktore wat wynkwaliteit beïnvloed kan gemanipuleer word in die wingerd deur verskeie
verbouingstegnieke toe te pas en in die kelder deur die toepassing van verskillende
wynbereidingsmetodes. Die bydrae van sade tot die finale tannienkonsentrasie in rooiwyn is
groot in vergelyking met dié van die pulp en doppe. Tanniene dra by tot die verouderingspotensiaal,
organoleptiese eienskappe en die stabilisasie van die wynkleur. Die kleur van ‘n rooi
wyn word ook beïnvloed deur appelmelksuurgisting (AMG), die biologiese proses wat appelsuur
omskakel na melksuur en ‘n gevolglike toename in die pH van die wyn veroorsaak. Hierdie
verandering in die pH van die wyn beïnvloed die antosianien ewewig, die primêre kleur
komponente teenwoordig in rooiwyn. Suurstof dra by tot die polimerisasie van antosianiene oor
tyd om meer stabiele kleur pigmente te vorm met ‘n hoër kleurintensiteit wat minder sensitief is
teenoor pH veranderinge en die bleikingseffek van swaweldioksied. Beperkte navorsing is
gedoen op die gebruik van suurstof na alkoholiese gisting en die impak daarvan op die
fenoliese samestelling van ‘n rooiwyn. Slegs ‘n paar studies het die invloed van die verwydering
of byvoeging van sade in kombinasie met suurstoftoediening op ‘n rooiwyn se fenoliese
samestelling ondersoek. Dit wil voorkom of beperkte gepubliseerde data beskikbaar is oor die
effek wat verskillende pH’s het op rooi wyn se fenoliese en kleurontwikkeling na suurstof
byvoeging.
Ons resultate het aangedui dat dit wel moontlik is om in sekere gevalle die kleur van ‘n
rooiwyn te stabiliseer deur addisionele sade by te voeg voor alkoholiese fermentasie. Hierdie
byvoeging het ‘n toename in kleurintensiteit tot gevolg gehad. Sekere wyne wat gemaak is
sonder sade het ‘n kenmerkend laer kleur intensiteit gehad. Hierdie bevinding is ‘n duidelike
bewys dat katesjiene en prosianidiene geëkstraheer word vanuit die sade en bydra tot wynkleur
deurdat hulle met ander pigmente verbind om die kleur sodoende te stabiliseer.
Spektrofotometriese en hoë druk vloeistof chromatografie (HDVC) analises het gewys dat die
totale fenoliese konsentrasie neem toe met ‘n toename in saad konsentrasie. Daar is egter
waargeneem dat ‘n wyn moontlik versadig kan raak met fenole wanneer addisionele sade
bygevoeg word. Antosianien konsentrasies het meestal afgeneem wanneer suurstof bygevoeg
is, maar polimeriese fenole en polimeriese pigmente het partykeer toegeneem.
Met die toediening van verskillende suurstof dosisse tot ‘n rooiwyn op kommersiële skaal
het ons bevind dat monomeriese antosianiene afneem wanneer meer suurstof bygevoeg word.
Hierdie afname in antosianiene het egter gelei tot die vorming van stabiele polimeriese
pigmente. Dié bevinding was gereflekteer in die toename in kleurintensiteit van wyne wat met
suurstof behandel is. Klein verskille was waargeneem vir die totale fenol en tannien
konsentrasies tussen die kontrole en wyne behandel met suurstof. Sekere van hierdie fenoliese
kleur verskille het egter afgeneem tydens die daaropvolgende veroudering van die wyne.
Wyne wat gemaak is met verskillende aanvanklike pH’s se kleurintensiteit neem af soos
die pH toeneem. Die toediening van suurstof het die kleurverlies tydens AMG verminder, veral
by ‘n laer pH. Die toediening van suurstof het nie verskillende polimeriese pigment
konsentrasies by verskillende pH’s veroorsaak nie, maar ‘n verskil kon moontlik waargeneem
word indien die wyne verouder was. pH verskille tussen 3.4 en 4.0 het egter nie die fenoliese
samestelling van die wyne onder ons omstandighede beduidend beïnvloed nie. Hierdie studie
het gelei tot meer kennis oor die effek van suurstoftoedienings onder verskillende kondisies op
rooiwyn se fenoliese en kleursamestelling.
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Classifying South African Chenin blanc wine stylesBester, Inneke 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2011 / ENGLISH ABSTRACT: South African Chenin blanc wine is characterised by its style diversity and has been receiving
more industry limelight over the past few years. Three dry Chenin blanc wine styles are
currently described by the wine industry as Fresh and Fruity (FF), Rich and Ripe unwooded
(RR-unwooded) and, Rich and Ripe wooded (RR-wooded). According to the South African wine
industry, however, consumers seem to be somewhat confused by these various Chenin blanc
wine styles, which have not yet been clearly defined and classified. During this study we
investigated the following perspectives of this wine style classification confusion:
Currently, no specified sensory method is being used to differentiate between wine styles of
a single wine cultivar, such as Chenin blanc. The sorting method can be used as a more cost
and time effective classification and profiling method than general quantitative descriptive
analysis (QDA). It was therefore investigated whether both uninstructed and instructed sorting,
with consumers and wine experts, can be used to classify and describe the Chenin blanc wine
styles similarly to QDA. The increase in young wine consumers, Generation Y, introduces new
wine marketing opportunities for the wine industry which need to be investigated. Young
consumers are not aware of the various Chenin blanc wine styles, which may influence their
wine preferences. The influence of wine style knowledge on these consumers’ wine style
preferences were investigated during blind and wine style informed preference test. Any
segmentation within this Generation Y group was also investigated with regards to their Chenin
blanc wine style preferences and/or exploratory data. The following scientific and industrial
findings were made:
QDA was successfully substituted by instructed and uninstructed sorting tasks. Although the
sorting tasks easily differentiated between wooded and unwooded wines, QDA differentiated
more successfully between the unwooded wines. Wine tasting experience did not significantly
influence the sorting results of the consumers versus the wine experts, but more experienced
panellists consistently used fewer descriptors than untrained consumers. All panellists sorted
products slightly better when they were provided with wine style sorting instructions. However,
there were no significant differences between the instructed and uninstructed sorting task
results, i.e. a wine style descriptor list did not improve panellists’ abilities to describe their sorted
wine groups.
South African Chenin blanc wines can definitely be divided into wooded and unwooded
wine styles, i.e. two wine style groups, but the unwooded Chenin blanc wine spectrum formed a
wine-style-continuum. This finding is apparent from both the sorting and QDA methods. The
unwooded continuum wines can further be differentiated from one another with the use of a
fresh-to-mature scale and/or a light-to-full body scale during QDA.
Generation Y wine consumers preferred all the Chenin blanc wine styles equally and
moderately during the blind tasting, but their knowledge of the wine style concepts significantly
increased their preferences for the wines during the informed wine style tasting. The cognitive
influence of wine style knowledge is therefore powerful in terms of influencing a consumer’s
wine preferences. Other interesting correlations were also made between Generation Y
consumers’ wine style preferences and their exploratory data. / AFRIKAANSE OPSOMMING: Suid-Afrikaanse Chenin blanc wyn word gekarakteriseer deur styl diversiteit en is die afgelope
paar jaar meer in die kollig. Drie droë Chenin blanc wynstyle word tans deur die wynbedryf
beskryf as: Vars en Vrugtig, Ryk en Ryp ongehout en, Ryk en Ryp gehout. Volgens die Suid-
Afrikaanse wynbedryf is daar heelwat verwarring is tussen hierdie Chenin blanc wynstyle weens
die feit dat hierdie wynstyle nog nie duidelik gedefinieer en geklassifiseer is nie. Tydens die
huidige studie het ons die volgende perspektiewe van hierdie wynstyl-verwarring ondersoek:
Huidiglik word daar geen gespesifiseerde sensoriese metode gebruik om te onderskei
tussen verskillende wynstyle van ’n enkele wyn kultivar, soos Chenin blanc, nie. Die
sorteringsmetode kan gebruik word, instede van kwantitatiewe beskrywende analise, as ’n meer
koste- en tyd-effektiewe produk klassifikasie en profileringsmetode. DIt was dus ondersoek of
beide geïnstrukteerde en ongeïnstrukteerde sorteringstake, met verbruikers en wynkundiges,
gebruik kan word om die verskeie Chenin blanc wynstyle kan profileer en klassifiseer soortgelyk
soos kwantitatiewe beskrywende analise. Die toename in jong verbruikers, Generasie Y, skep
nuwe wynbemarkingsgeleenthede wat ondersoek moet word. Jong verbruikers se
onbewustheid van die verskeidenheid Chenin blanc wynstyle mag hulle voorkeure vir hierdie
wyne beïnvloed. Die invloed van wynstyl kennis op hierdie jong verbruikers se wynstyl
voorkeure was ook ondersoek gedurende ’n blinde en ’n wynstyl-ingeligte voorkeur toets. Enige
segmentasie binne hierdie Generasie Y verbruikersgroep was ook ondersoek in verband met
hul Chenin blanc wynstyl voorkeure en/of verkennende data. Die volgende wetenskaplike en
industriële bevindings is gemaak:
Kwantitatiewe beskrywende analise kan suksesvol vervang word deur beide
geïnstrukteerde en ongeïnstrukteerde sorteringsmetodes. Alhoewel die sorteringsmetodes
maklik gebruik kon word om te onderskei tussen gehoute en ongehoute wyne, kan
kwantitatiewe beskrywende analise fyner onderskeid tref tussen die individuele ongehoute
wyne. Die wynproe-ervaringsvlak het geen invloed op die sorteringsresultate gehad nie, maar
meer ervare paneellede het konsekwent gebruik gemaak van minder beskrywende terme as
onopgeleide verbruikers wat baie meer en verskillende soorte terme gebruik het. Beide panele
het effens beter gesorteer wanneer hulle spesifieke wynstyl sorteringsinstruksies ontvang het.
Daar was egter geen beduidende verskille tussen die geïnstrukteerde en ongeïnstrukteerde
sorteringsresultate nie, wat daarop dui dat sorteringsinstruksies en ’n lys van wynstyl
beskrywings nie die paneellede se wyse van sortering verander het nie.
Suid-Afrikaanse Chenin blanc wyne kan definitief verdeel word in gehoute en ongehoute
wynstyle, d.w.s twee wynstyl groepe, maar die ongehoute Chenin blanc wyn spektrum vorm ’n
wynstyl-kontinuum. Laasgenoemde is bevind tydens beide die sorteringstake asook
kwantitatiewe beskrywende analise. Die ongehoute kontinuum wyne kan verder van mekaar
onderskei word met behulp van ‘n vars-tot-volryp en/of ‘n ligte-tot-volmond skaal tydens
kwantitatiewe beskrywende analise.
Alle jong wyn verbruikers het ewe veel van al die wynstyle gehou tydens die blinde wynstyl
voorkeur toets, maar tydens die wynstyl-ingeligte voorkeur toets het hulle voorkeure vir al die
wynstyle drasties verbeter. Die kognitiewe invloed van Chenin blanc wynstyl kennis kan dus lei
tot hoër voorkeure vir die wynstyle. Ander interessante korrelasies is ook bevind tussen hierdie
Generasie Y wyn verbruikersgroep se wynstyl voorkeure en hul verkennende data.
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Volatiles playing an important role in South African Sauvignon blanc winesVan Wyngaard, Elizma 03 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Sauvignon blanc wines have become progressively more important in the commercial market.
Extensive research is being done in various countries to gain more understanding about the
aroma compounds found in Sauvignon blanc wines and the interactions between them.
Sauvignon blanc wines often have either have a green or tropical style. The green style is
caused by the methoxypyrazines while the volatile thiols are important contributing compounds
to the tropical style. Various international studies have focussed on measuring the chemical
composition of Sauvignon blanc wines. However, more research is required on South African
Sauvignon blanc wines. Little is known of the volatile thiols content of South African Sauvignon
blanc wines, although the methoxypyrazine content has been extensively reported on. Although
methoxypyrazines and volatile thiols are seen as the most important aroma compounds
contributing to Sauvignon blanc character, other compounds contribute as well. Esters,
monoterpenes and phenols have been found to influence Sauvignon blanc aroma and interact
with the methoxypyrazines and volatile thiols. The complex interaction between the compounds
responsible for the aroma of Sauvignon blanc wines are still not fully understood and further
research is thus needed. The first part of the current study investigated the interaction between
a specific methoxypyrazine and volatile thiol. Five different concentrations of 2-isobutyl-3-
methoxypyrazine (ibMP) and 3-mercaptohexan-1-ol (3MH) were spiked in dearomatize, neutral
Sauvignon blanc wine. The single compounds as well as every possible combination of the
range of concentrations were evaluated using sensory descriptive analysis. It was found using
various statistical approaches that ibMP suppressed the tropical attributes associated with 3MH
and that 3MH suppressed the green attributes that correlated with ibMP. The concentrations at
which the suppression occurred and the degree of suppression was different for each attribute.
The second part of the current study focussed on commercial South African Sauvignon blanc wines. Sensory descriptive analysis and chemical analysis were used to assess the wines and
measure the volatile thiol and methoxypyrazine concentrations. The concentrations of volatile
thiols and methoxypyrazines were found to be in line with international Sauvignon blanc wines.
It was also shown for the first time that the mutually suppressive trend between the volatile
thiols and methoxypyrazines can be seen in commercial Sauvignon blanc wines as well. Future
work is needed to fully understand the complex interaction between the various compounds in
Sauvignon blanc wines. Further research could focus on investigating the mechanism of
interaction between the volatile thiols and methoxypyrazines as well as other aroma
compounds. / AFRIKAANSE OPSOMMING: Sauvignon blanc-wyne word toenemend belangriker in die kommersiële mark. Omvattende
navorsing word in etlike lande gedoen om meer begrip te ontwikkel van die aromaverbindings
wat in Sauvignon blanc-wyne teenwoordig is, asook van die interaksies tussen hulle. Sauvignon
blanc-wyne het in baie gevalle óf ’n groen óf ’n tropiese styl. Die groen styl word veroorsaak
deur metoksipirasiene, terwyl die vlugtige tiole belangrike bydraende verbindings is wat
aanleiding gee tot die tropiese style. Verskeie internasionale studies het reeds gefokus op die
meet van die chemiese samestelling van Sauvignon blanc-wyne, maar meer navorsing is nodig
oor Suid-Afrikaanse Sauvignon blanc-wyne. Min is bekend oor die inhoud van vlugtige tiole in
Suid-Afrikaanse Sauvignon blanc-wyne, hoewel daar reeds op groot skaal oor die
metoksipirasieninhoud verslag gedoen is. Hoewel metoksipirasiene en vlugtige tiole die
belangrikste aromaverbindings is wat tot Sauvignon blanc-karakter bydra, is daar ook ander
verbindings wat ’n bydrae maak. Esters, monoterpene en fenole het almal ’n invloed op
Sauvignon blanc-aroma en reageer op die metoksipirasiene en vlugtige tiole. Die komplekse
interaksie tussen die verbindings wat vir die aroma van Sauvignon blanc-wyne verantwoordelik
is, word nog nie volledig begryp nie en verdere navorsing is nodig. Die eerste deel van die
huidige studie het die interaksie tussen ’n spesifieke metoksipirasien en vlugtige tiol ondersoek.
Vyf verskillende konsentrasies van 2-isobutiel-3-metoksipirasien (ibMP) en 3-merkaptoheksaan-
1-ool (3MH) is by ontgeurde, neutrale Sauvignon blanc-wyn gevoeg. Die enkel verbindings,
asook elke moontlike kombinasie van die reeks konsentrasies, is deur middel van beskrywende
sensoriese analise geëvalueer. Daar is met behulp van verskillende statistiese benaderings
gevind dat ibMP die tropiese eienskappe wat verband hou met 3MH onderdruk het, terwyl 3MH
die groen eienskappe wat verband hou met ibMP onderdruk het. Die konsentrasies waarteen
die onderdrukking plaasgevind het en die vlak van onderdrukking het vir elke eienskap verskil. Die tweede deel van die studie het gefokus op kommersiële Suid-Afrikaanse Sauvignon blancwyne.
Beskrywende sensoriese analise en chemiese analise is gebruik om die wyne te
assesseer en die konsentrasies van vlugtige tiole en metoksipirasiene te meet. Die
konsentrasies vlugtige tiole en metoksipirasiene was in lyn met dié van internasionale
Sauvignon blanc-wyne. Daar is ook vir die eerste keer gewys dat die wedersyds
onderdrukkende tendens tussen die vlugtige tiole en metoksipirasiene ook in kommersiële
Sauvignon blanc-wyne gevind word. Toekomstige werk sou kon fokus op ’n begrip van die
komplekse interaksie tussen die verskillende verbindings in Sauvignon blanc-wyne. Verdere
navorsing sou ook kon fokus op ’n ondersoek van die meganisme van interaksie tussen die
vlugtige tiole en metoksipirasiene, sowel as ander aromaverbindings. / The South African Wine Industry (Winetech), THRIP and the NRF for financial support
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Recherches sur les bases moléculaires de la saveur sucrée des vins secs : approches analytique et sensorielle / Reserach on molecular bases of sweetness in dry wines : analytical and sensorial approachesMarchal, Axel 15 December 2010 (has links)
La saveur sucrée est à l’origine de l’équilibre gustatif des vins secs. On observe uneaugmentation de son intensité au cours de la macération post-fermentaire et de l’élevage enbarrique. Nous montrons que ces phénomènes sont respectivement liés à la libération depeptides de la levure et de composés non-volatils du bois de chêne dans les vins.Le rôle de la protéine Hsp12 de S. cerevisae sur le gain de sucrosité est établi enutilisant des techniques de biologie moléculaire et d’analyse sensorielle.Le développement d’un couplage chromatographie de partage centrifuge –gustatométrie permet de fractionner un extrait de bois de chêne et de purifier plusieurscomposés sapides. L’utilisation de la LC-FT/MS et de la RMN nous a permis d’identifierquatre nouvelles molécules, appelées quercotriterpénosides (QTT), deux d’entre elles (QTTI et III) possédant une saveur douce. Les seuils de perception du QTT I et d’un lignane amer,le lyonirésinol, sont respectivement 590 μg/L et 1.52 mg/L.La mise au point d’une méthode de quantification de ces composés en LC-FT/MS nous apermis de démontrer l’impact organoleptique du lyonirésinol dans les vins.Il est probable que les QTT I et III contribuent, directement ou indirectement, au gain desucrosité conféré par le bois de chêne. / Sweetness contributes to the balance in taste of dry wines. An increase in sweet taste isobservable during post-fermentation maceration and oak-barrel aging. We have revealed thatthese phenomena are respectively due to the release in wines of yeast peptides and nonvolatileoak wood compounds.The role of Hsp12 protein from S.cerevisae on the increase in sweetness is establishedwith both molecular biology and sensorial analysis techniques.The development of a method coupling centrifugal partition chromatography andgustatometry has enabled us to fractionate an oak-wood extract and to purify several sapidcompounds. Thanks to both the LC-FTMS and the NMR spectroscopy methods, we havehighlighted four new molecules, called quercotriterpenosides (QTT), out of which QTT Iand III are responsible for a sweet taste. The perception thresholds of QTT I and a bitterlignan, lyoniresinol, are respectively 590 μg/L and 1.52 mg/L.LC-FT/MS method has been used to develop a quantification method for these compoundsand we have demonstrated the organoleptic impact of lyoniresinol in wines.QTT I and III are likely to contribute, directly or indirectly, to the increase in sweetnessconsecutive to barrel aging in dry wines.
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Estudo não-invasivo de vinhos tintos em garrafas lacradas através de RMN ¹H no domínio do tempo e análise multivariada / Non-invasive study of red wines in sealed bottles using 1H NMR in time domain and multivariate analysisScherrer, Esther Machado 15 February 2016 (has links)
A análise de qualidade de vinhos é altamente requisitada no setor da enologia. No entanto, o simples ato de abrir a garrafa desvaloriza o produto, sendo necessário o desenvolvimento de métodos alternativos não-invasivos. Atualmente, dois métodos não-invasivos têm sido propostos para análise da qualidade de vinhos em garrafas lacradas: análise do perfil diamagnético e espectroscopia de ressonância magnética (RMN) em alta resolução, usando um ímã de tomógrafo de RMN. No entanto, esses métodos têm baixa seletividade e/ou usam aparelhos que custam milhares de dólares, o que limita seu uso rotineiro. Neste trabalho de mestrado avaliou-se o uso de métodos rápidos de medidas relaxométricas (T1 e T2) para estudar vinhos diretamente nas embalagens lacradas. Neste tipo de medida utilizou-se um equipamento de RMN 1H no domínio do tempo, de baixo custo, baseado em um ímã permanente tipo Halbach de 0,23 T e 10 cm de bore livre utilizando as sequências de pulso CPMG e CP-CWFPx-x. Os dados obtidos foram comparados com medidas realizadas em um equipamento de RMN-DT padrão, mais homogêneo, porém que requer a abertura da garrafa. Todos os decaimentos obtidos foram tratados com ferramentas quimiométricas, correlacionando os dados multivariados com medidas dos metais paramagnéticos ferro, manganês e cobre de cada vinho. Os resultados mostraram que a variação de relaxação dos vinhos ocorreu devido à concentração de Mn2+, que tem uma relaxatividade maior do que o Fe3+ e o Cu2+. Portanto, os resultados mostram que os vinhos de diferentes origens geográficas têm diferentes perfis de relaxação conforme a concentração de metais absorvidos durante o crescimento das uvas, inerente às propriedades edafoambientais de seu local de origem (terroir). / The quality control of wines is highly requested in the enology sector. However, opening the bottle devalues the product, therefore it\'s necessary to develop alternative and non-invasive ways of analysis. Nowadays two non-invasive methods have been proposed to analyze wine in sealed bottles: diamagnetic profile of the bottle and high resolution nuclear magnetic spectroscopy (NMR) using an NMR imaging magnet (MRI). These methods, though, have low selectivity and/or use expensive hardware, making it\'s usage limited. In this study, rapid methods to measure the relaxometric constants (T1 and T2) were evaluated to study wines directly in sealed bottles. To do that it was used a 1H TD-NMR equipment of low cost, based on a permanent Halbach magnet with 0,23T and a 10cm bore. CPMG and CP-CWFPx-x pulse sequences were used and the results were compared to the ones obtained by standard TD-NMR equipment, which is more homogeneous but requires the bottle to be opened. The NMR decays obtained with these two sequences were treated using chemometric tools and correlated to paramagnetic ions content in the samples (Fe3+, Mn2+ and Cu2+). The results show that variation of wine relaxation time is related to the the Mn2+ content, that has higher relaxivity than Fe3+ and Cu2+. As consequence, wine from different geographic origins have different relaxation profiles due to the presence of metals absorbed by the grapes whilst their growth. The metal concentrations in grapes are inherent to soil and environmental properties of the wines origin site (terroir).
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Estudo não-invasivo de vinhos tintos em garrafas lacradas através de RMN ¹H no domínio do tempo e análise multivariada / Non-invasive study of red wines in sealed bottles using 1H NMR in time domain and multivariate analysisEsther Machado Scherrer 15 February 2016 (has links)
A análise de qualidade de vinhos é altamente requisitada no setor da enologia. No entanto, o simples ato de abrir a garrafa desvaloriza o produto, sendo necessário o desenvolvimento de métodos alternativos não-invasivos. Atualmente, dois métodos não-invasivos têm sido propostos para análise da qualidade de vinhos em garrafas lacradas: análise do perfil diamagnético e espectroscopia de ressonância magnética (RMN) em alta resolução, usando um ímã de tomógrafo de RMN. No entanto, esses métodos têm baixa seletividade e/ou usam aparelhos que custam milhares de dólares, o que limita seu uso rotineiro. Neste trabalho de mestrado avaliou-se o uso de métodos rápidos de medidas relaxométricas (T1 e T2) para estudar vinhos diretamente nas embalagens lacradas. Neste tipo de medida utilizou-se um equipamento de RMN 1H no domínio do tempo, de baixo custo, baseado em um ímã permanente tipo Halbach de 0,23 T e 10 cm de bore livre utilizando as sequências de pulso CPMG e CP-CWFPx-x. Os dados obtidos foram comparados com medidas realizadas em um equipamento de RMN-DT padrão, mais homogêneo, porém que requer a abertura da garrafa. Todos os decaimentos obtidos foram tratados com ferramentas quimiométricas, correlacionando os dados multivariados com medidas dos metais paramagnéticos ferro, manganês e cobre de cada vinho. Os resultados mostraram que a variação de relaxação dos vinhos ocorreu devido à concentração de Mn2+, que tem uma relaxatividade maior do que o Fe3+ e o Cu2+. Portanto, os resultados mostram que os vinhos de diferentes origens geográficas têm diferentes perfis de relaxação conforme a concentração de metais absorvidos durante o crescimento das uvas, inerente às propriedades edafoambientais de seu local de origem (terroir). / The quality control of wines is highly requested in the enology sector. However, opening the bottle devalues the product, therefore it\'s necessary to develop alternative and non-invasive ways of analysis. Nowadays two non-invasive methods have been proposed to analyze wine in sealed bottles: diamagnetic profile of the bottle and high resolution nuclear magnetic spectroscopy (NMR) using an NMR imaging magnet (MRI). These methods, though, have low selectivity and/or use expensive hardware, making it\'s usage limited. In this study, rapid methods to measure the relaxometric constants (T1 and T2) were evaluated to study wines directly in sealed bottles. To do that it was used a 1H TD-NMR equipment of low cost, based on a permanent Halbach magnet with 0,23T and a 10cm bore. CPMG and CP-CWFPx-x pulse sequences were used and the results were compared to the ones obtained by standard TD-NMR equipment, which is more homogeneous but requires the bottle to be opened. The NMR decays obtained with these two sequences were treated using chemometric tools and correlated to paramagnetic ions content in the samples (Fe3+, Mn2+ and Cu2+). The results show that variation of wine relaxation time is related to the the Mn2+ content, that has higher relaxivity than Fe3+ and Cu2+. As consequence, wine from different geographic origins have different relaxation profiles due to the presence of metals absorbed by the grapes whilst their growth. The metal concentrations in grapes are inherent to soil and environmental properties of the wines origin site (terroir).
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SHELF - LIFE DI VINI BIANCHI E ROSSI TAPPATI CON CHIUSURE A VITE / SHELF-LIFE OF WHITE AND RED WINES BOTTLED UNDER SCREWCAPSGRILLO, ELENA 20 February 2009 (has links)
Oggigiorno diversi tipi di chiusure sono disponibili sul mercato e, tra queste, le chiusure a vite che sono molto diffuse nei paesi emergenti nel settore viti-vinicolo.
L’uso dei tappi a vite, comunque, non è attualmente diffuso in relazione ai vini da invecchiamento o di alta qualità poiché a tale chiusura è associato un ambiente riducente che viene considerato poco idoneo alla conservazione di vini rossi da invecchiamento.
Lo scopo di questo lavoro è stato quello di valutare, tramite analisi chimiche e sensoriali, l’evoluzione del vino tappato con diverse tipologie di chiusure a vite rispetto al sughero tradizionale e la bontà di diverse possibili condizioni di imbottigliamento.
Nel corso dei tre anni di attività di dottorato sono state condotte diverse prove per testare capsule in fase di sperimentazione in confronto con chiusure a vite già impiegate in ambito enologico e con tappi sintetici e di sughero. Differenti tipologie di vino, associate a diverse tipologie di imbottigliamento e di tappi, sono state utilizzate. Alcune prove sono state condotte a termine nel breve periodo (9 mesi) mentre altre hanno richiesto tempi più lunghi.
In linea generale, i risultati evidenziano, per tutti i vini, che il tempo di conservazione in bottiglia incide in maniera più significativa delle chiusure sull’evoluzione compositiva ed organolettica dei prodotti.
Nel caso dei vini bianchi, il breve periodo di maturazione in bottiglia considerato non ha evidenziato differenze di composizione significative imputabili alla chiusura.
Nel caso del Barbera Oltrepò Pavese i tempi lunghi di conservazione (36 mesi) hanno evidenziato che la chiusura esercita un effetto di separazione tra i vini.
Quando la temperatura di stoccaggio è elevata (ad esempio 45°C) la shelf-life del prodotto si abbrevia in modo più evidente quando il prodotto è giovane. / Nowadays, there are different types of closures available on the market and, behind these, the screwcaps are very diffused in emerging enological countries.
Screwcaps, however, are not used for premium or aged wines because their use is linked to a reductive environment in bottle, which is not useful for the maturation of aged red wines.
The aim of this work was the evaluation, through chemical and sensorial analysis, of the evolution of wine, bottled with different types of closures and bottling conditions.
During the PhD work time, different trails on experimental capsules and classical screwcaps, synthetic closures and cork closures were carried out.
Several types of white and red wine, bottled in different conditions and with diverse kinds of closures, were studied. Some of the trials ended in a few months while others were longer.
The results showed, for all wines, that the storage period had a significant influence on the wine evolution, more than the closure type had.
The closures used for white wines in short periods of storage had no influence on the wine composition.
For the Barbera Oltrepò Pavese wine, after the long storage period (36 months), the closure type exhibited a separation effect.
The high storage temperature (e.g. 45°C) reduced the shelf-life of the product, particularly in case of young wines.
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RESÍDUOS DE FUNGICIDAS EM VINHOS DE DIFERENTES PROPRIEDADES VITIVINÍCOLAS DO RIO GRANDE DO SUL, BRASIL, FRENTE AO USO DA TECNOLOGIA THERMAL PEST CONTROL A CAMPO / FUNGICIDE RESIDUES IN WINES OF WINE PROPERTIES OF RIO GRANDE DO SUL, BRAZIL, REGARDING THE USE OF THERMAL PEST CONTROL TECHNOLOGY IN THE FIELDSMozzaquatro, Joseane de Oliveira 06 March 2015 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The use of chemical compounds in the wine industry is extremely high, thus, it is appropriate to identify and quantify pesticide residues in wine because grapes are one of the fruits with the highest number of pesticide applications in the country's agriculture. In order to reduce the use of pesticides, some winemakers have been using the Thermal Pest Control (TPC) technology in the management of their vineyards as an alternative to control pests. It is a technology that provides the high temperatures vines, providing a greater antimicrobial resistance. The objective of this study was to identify and quantify fungicides in white and red wines produced from grapes with and without the use of TPC technology for their cultivation in different wine properties of Rio Grande do Sul. Samples of Tannat, Chardonnay and Cabernet Sauvignon varieties from the 2011/2012, 2012/2013 and 2013/2014 harvests were collected in three wine properties of RS. Vinification process was performed in laboratory scale separately for grapes using no TPC technology (control) and grapes using TPC (TPC). The modified QuEChERS acetate method was used for sample preparation. Afterwards, analyzes were carried out using UHPLC-MS/MS for determination of fungicides. Boscalid, procymidone, pyraclostrobin, pyrimethanil, thiophanate-methyl and tetraconazole were detected above the LOQ in both treatments. In control and with TPC, pyrimethanil presented higher frequency (85.71%) and averages (26.33 and 30.16 μg L-1), respectively. There was no significant difference between the white and red wines. In Chardonnay wines, 2012/2013 harvests, the fungicide pyrimethanil was statistically different, with an average of 64.67 μg L-1 (control), and 111.12 μg L-1 (TPC), thus, higher levels for wines with the use of TPC technology were observed. In Chardonnay wines, 2013/2014 harvests, showed the higher average of procymidone in control (6.47 μg L-1) than in treatment with TPC (0.46 μg L-1). In Cabernet Sauvignon wines, 2013/2014 harvests, presented a higher average of procymidone in treatment with TPC (129.73 μg L-1) than in control (3.69 μg L-1). Therefore, the presence of fungicide residues was observed in this study, but none of the compounds presented levels above the MRL established for grapes considering their mass corrections. These results show higher concentrations of residues for those wines produced from grapes submitted to TPC technology. We found no references in literature about fungicide residues in wine whose grapes were submitted to this technology, which leads us to believe this is the first study on the subject. / O uso de compostos químicos em vitivinicultura é extremamente elevado. Neste sentido, torna-se oportuno identificar e quantificar resíduos de pesticidas em vinhos, pois as uvas figuram a lista de maior número de aplicações de pesticidas na agricultura do país. Com intuito de reduzir o uso de pesticidas, alguns vitivinicultores utilizam a tecnologia Thermal Pest Control (TPC) no manejo de seus vinhedos, como forma alternativa no combate às pragas. Trata-se de uma tecnologia que gera e fornece elevadas temperaturas às videiras, conferindo uma maior resistência microbiana. O objetivo deste estudo foi identificar e quantificar fungicidas em vinhos brancos e tintos, oriundos de diferentes propriedades vitivinícolas do Rio Grande do Sul, produzidos a partir de uvas com e sem o emprego da tecnologia TPC durante o seu cultivo. Foram cedidas amostras das variedades Tannat, Chardonnay e Cabernet Sauvignon nas safras 2011/2012, 2012/2013 e 2013/2014. Realizaram-se vinificações em escala laboratorial e separadamente para aquelas uvas sem o emprego da tecnologia TPC (controle) daquelas que fizeram uso desta (com TPC). No preparo das amostras utilizou-se o método QuEChERS acetato modificado. Após, as análises procederam-se em UHPLC-MS/MS para determinação dos fungicidas. Boscalida, procimidona, piraclostrobina, pirimetanil, tetraconazol e tiofanato-metílico foram detectados acima do LOQ em ambos os tratamentos. Nos tratamentos, controle e com TPC, o pirimetanil obteve maior frequência (85,71%) e médias (26,33 e 30,16 μg L-1), respectivamente. Não houve diferença significativa para os dois tipos de vinhos (tintos e brancos). Nos vinhos da cv. Chardonnay, safra 2012/2013, o fungicida pirimetanil diferiu estatisticamente (p=0,021), com média de 64,67 μg L-1 (controle), e de 111,12 μg L-1 (com TPC), apresentando níveis superiores para os vinhos com a utilização da tecnologia TPC. Já nos vinhos da cv. Chardonnay, safra 2013/2014, o procimidona apresentou média superior no controle (6,47 μg L-1), do que no tratamento com TPC (0,46 μg L-1). E nos vinhos da cv. Cabernet Sauvignon, safra 2013/2014, cujas uvas foram produzidas na propriedade vitivinícola C‟, o composto procimidona obteve média superior para o tratamento com TPC (129,73 μg L-1), do que em relação ao controle (3,69 μg L-1). Diante do exposto, a presença de resíduos de fungicidas foi confirmada neste estudo, porém nenhum dos compostos mostrou-se acima dos LMRs estabelecidos para as uvas, considerando suas correções de massa. Tais resultados demonstraram concentrações de resíduos superiores para aqueles vinhos produzidos a partir de uvas submetidas à tecnologia TPC. Não foram encontradas referências na literatura que abordem resíduos de fungicidas em vinhos, cujas uvas fossem submetidas a esta tecnologia, o que nos leva a deduzir que este seja o primeiro estudo realizado sobre o tema.
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