Thesis (M.S.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 14, 2009) Includes bibliographical references.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on Sept. 21, 2009). Thesis advisor: Dr. Azlin Mustapha. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:23:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-03-02Bitstream added on 2014-06-13T20:50:19Z : No. of bitstreams: 1 castilhos_mbm_me_sjrp.pdf: 1071030 bytes, checksum: f14702dde72be9a4e5de9ce2792b0040 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A atividade vitivinícola do estado de São Paulo é caracterizada pela produção de vinhos de mesa. Nesse contexto, este trabalho objetivou desenvolver e caracterizar os vinhos, de duas safras, das uvas Bordô e Isabel, provenientes da região noroeste do estado de São Paulo, obtidos de três tratamentos: tradicional, pré-secagem e bagaço estático e suas avaliações sensoriais frente a marcas comerciais de grande aceitação. Todos os vinhos apresentaram propriedades físico-químicas conformes à legislação, exceto os vinhos do tratamento pré-secagem que apresentaram índice de acidez além do limite máximo. Os vinhos pré-secagem apresentaram elevados teores de extrato seco, teor de fenólicos totais e índices de cor, pressupondo a concentração desses compostos pela ação do calor. Sensorialmente, os vinhos produzidos foram mais aceitos que os vinhos comerciais, em ambas as safras. Os vinhos pré-secagem foram mais aceitos na primeira safra, em contrapartida, os vinhos do tratamento bagaço estático foram mais aceitos na segunda safra. As propriedades físico-químicas e sensoriais mostraram uma intensa relação do teor alcoólico com o aroma e o corpo, assim como a influência do teor de fenólicos totais e índices de cor com a aparência e a aceitação global. Além disso, em alguns casos, o extrato seco foi relacionado com o corpo dos vinhos e da acidez com o sabor. O teor de açúcares redutores também influenciou na aceitação do aroma. Os resultados físico-químicos mostraram que os aspectos inerentes às safras influenciaram algumas determinações físico-químicas como acidez, extrato seco e teor de fenólicos totais. A maior aceitação sensorial dos vinhos desenvolvidos no estudo em relação às marcas comerciais e a qualidade físico-química e sensorial comprovaram o potencial dos tratamentos alternativos de vinificação / The wine production in São Paulo, considered, nowadays, as an ascending region in vitiviniculture, is characterized by the production of table wines. In this context, this study aimed to develop and characterize the wines, from two vintages, of Bordô and Isabel grapes from the northwest region of São Paulo state, regarding to three treatments: traditional, pre-drying and static pomace and their sensory evaluations when compared to commercial wines with high acceptance. All wines presented physicochemical in accordance to law, and the pre-drying wines showed the highest levels of acidity, dry extract, total phenolic content and color indexes, assuming the concentration of these compounds by the action of the heat. In sensory approach, the studied wines were more accepted when compared to commercial wines in both seasons. The wines from pre-drying process presented higher acceptance in first vintage and static pomace wines were more accepted in second season. It was possible to observe intense relationship between alcoholic content with aroma and body, as well as the influence of the total phenolic content and color indexes in the appearance and overall acceptance. Moreover, in some cases, dry extract and acidity showed relationship with body and flavor acceptance, respectively. Reducing sugar content also influenced the acceptance of the aroma. All these relationships were reported in several scientific studies that researched wines from American and European grapes. Physicochemical results revealed that the inherent characteristics of the seasons affected some chemicals as acidity, dry extract and total phenolic content. The highest sensory acceptance of studied wines in comparison to commercial ones, and the physicochemical profile demonstrated the potential of these vinification processes as alternative in wine industry

Orientador: Vanildo Luiz Del Bianchi / Coorientador: Ana Carolina Conti e Silva / Banca: Waldemar Gastoni Venturini Filho / Banca: Roberto da Silva / Resumo: A atividade vitivinícola do estado de São Paulo é caracterizada pela produção de vinhos de mesa. Nesse contexto, este trabalho objetivou desenvolver e caracterizar os vinhos, de duas safras, das uvas Bordô e Isabel, provenientes da região noroeste do estado de São Paulo, obtidos de três tratamentos: tradicional, pré-secagem e bagaço estático e suas avaliações sensoriais frente a marcas comerciais de grande aceitação. Todos os vinhos apresentaram propriedades físico-químicas conformes à legislação, exceto os vinhos do tratamento pré-secagem que apresentaram índice de acidez além do limite máximo. Os vinhos pré-secagem apresentaram elevados teores de extrato seco, teor de fenólicos totais e índices de cor, pressupondo a concentração desses compostos pela ação do calor. Sensorialmente, os vinhos produzidos foram mais aceitos que os vinhos comerciais, em ambas as safras. Os vinhos pré-secagem foram mais aceitos na primeira safra, em contrapartida, os vinhos do tratamento bagaço estático foram mais aceitos na segunda safra. As propriedades físico-químicas e sensoriais mostraram uma intensa relação do teor alcoólico com o aroma e o corpo, assim como a influência do teor de fenólicos totais e índices de cor com a aparência e a aceitação global. Além disso, em alguns casos, o extrato seco foi relacionado com o corpo dos vinhos e da acidez com o sabor. O teor de açúcares redutores também influenciou na aceitação do aroma. Os resultados físico-químicos mostraram que os aspectos inerentes às safras influenciaram algumas determinações físico-químicas como acidez, extrato seco e teor de fenólicos totais. A maior aceitação sensorial dos vinhos desenvolvidos no estudo em relação às marcas comerciais e a qualidade físico-química e sensorial comprovaram o potencial dos tratamentos alternativos de vinificação / Abstract: The wine production in São Paulo, considered, nowadays, as an ascending region in vitiviniculture, is characterized by the production of table wines. In this context, this study aimed to develop and characterize the wines, from two vintages, of Bordô and Isabel grapes from the northwest region of São Paulo state, regarding to three treatments: traditional, pre-drying and static pomace and their sensory evaluations when compared to commercial wines with high acceptance. All wines presented physicochemical in accordance to law, and the pre-drying wines showed the highest levels of acidity, dry extract, total phenolic content and color indexes, assuming the concentration of these compounds by the action of the heat. In sensory approach, the studied wines were more accepted when compared to commercial wines in both seasons. The wines from pre-drying process presented higher acceptance in first vintage and static pomace wines were more accepted in second season. It was possible to observe intense relationship between alcoholic content with aroma and body, as well as the influence of the total phenolic content and color indexes in the appearance and overall acceptance. Moreover, in some cases, dry extract and acidity showed relationship with body and flavor acceptance, respectively. Reducing sugar content also influenced the acceptance of the aroma. All these relationships were reported in several scientific studies that researched wines from American and European grapes. Physicochemical results revealed that the inherent characteristics of the seasons affected some chemicals as acidity, dry extract and total phenolic content. The highest sensory acceptance of studied wines in comparison to commercial ones, and the physicochemical profile demonstrated the potential of these vinification processes as alternative in wine industry / Mestre

Thesis (MSc Food Sc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: In this study an industry-selected and diverse range of South African red wines were analysed for sensory and chemical attributes, as well as degree of liking using a target group of black South African consumers. Segments of consumers that differed in degree of liking were then tested for their response to intrinsic (sensory) and extrinsic (non-sensory) cues. The selection of wines included eighteen dry and natural sweet red wines, representing low-end inexpensive wines together with high-end, top quality wines. Sensory profiles for all samples were established using Quantitative descriptive analysis (QDA). The results revealed that cultivar specific dry red wines associated with a wide range of sensory descriptors such as woody, vegetative and fruity, while the sweet red wines associated with the fruity and sweet-associated attributes. Chemically there was a significant variation between wines regarding the alcohol and sugar content. Gas chromatography with flame ionisation detection (GC-FID) indicated the major volatile constituents present in the wine, i.e. esters, alcohols and fatty acids. When investigating the association between the chemical and sensory data, it was revealed that the red blends were driven by the presence of alcohols and esters, and sensory descriptors such as high roast oak, coffee and mixed spice, whereas the red cultivar wines were mostly driven by fatty acids and esters and the sensory descriptors, green bean and asparagus. The sweet red blends were closely associated with acids and the sensory descriptors sweet-associated and floral. Degree of liking of a subset of 18 wines was investigated based on the preferences of black consumers from the Western Cape area, South Africa. These consumers predominantly preferred the sweet red wines with high sugar content, in a blind tasting session. Purchase intent was also evaluated by viewing actual photographs of packaging formats of the respective wines and the results indicated that the consumers preferred the well-known cultivar wines with a perception of value and style. Cluster analysis was furthermore performed to ascertain whether these consumers differed in their degree of liking of the intrinsic character of the respective wines. Four different clusters of consumers were identified: 1) Consumers preferring both dry and sweet red wines equally, 2) Consumers who strongly favoured sweet red wines and moderately liked dry red wines, 3) Consumers who strongly favoured sweet red wines with little preference for dry red wines; and 4) Consumers preferring dry red wines. Consumers were also probed on their general opinions or perceptions on the extrinsic character of the wines, and thus factors that influence the purchasing process. It was found that black consumers who don‟t consume wine often, preferred wines that they are familiar with, while consumers that drink wine more frequently enjoy to broaden their horizons by experimenting with more expensive wine brands. Extrinsic or non-sensory cues such as alcohol content, label, vintage, price and cultivar were found to be the most important considered factors when purchasing red wines, while awards and type of closure were regarded as the least important. It was also found that the discerning consumers, who purchase high-end wines, took more of the latter aspects into consideration, whereas consumers who purchase low-end wines considered a limited number of the non-sensory cues. / AFRIKAANSE OPSOMMING: In hierdie studie is 'n diverse reeks industrie-geselekteerde, Suid-Afrikaanse rooiwyne geanaliseer vir hul sensoriese en chemiese eienskappe. Verbruikersvoorkeur van die wyne is getoets, asook tot watter mate verbruikersvoorkeure beïnvloed word deur intrinsieke (sensoriese) en ekstrinsieke (nie-sensoriese) faktore. Die reeks van agtien wyne het bestaan uit droë en soet rooi wyne, wat op hul beurt verder verdeel kan word in goedkoper, kwaliteit wyne en duurder, ultra-premium wyne. Die sensoriese profiel van al die wyne is bepaal deur beskrywende sensoriese analise. Resultate het getoon dat die kultivar-spesifieke droë rooiwyne geassosieer word met 'n wye reeks sensoriese eienskappe soos houtagtig, kruidagtig en vrugtig, terwyl die soet rooiwyne beskryf is as vrugtige en soet-geassosieerd. In terme van die chemiese analises was daar betekenisvolle verskille betreffende die alkohol- en suikerinhoud van die wyne. Gas chromatografie gekoppel met vlam-ioniserende deteksie (GC-FID) het die mees vlugtige verbindings teenwoordig in die wyn aangedui, naamlik esters, alkohole en vetsure. Met die korrelasie van die chemiese en sensoriese data is gevind dat die droë versnitwyne gedryf word deur die teenwoordigheid van alkohole en esters, asook sensoriese eienskappe soos gehout, koffie, en gemengde spesery, terwyl die kultivar-spesieke wyne weer meestal gedryf word deur vetsure en esters en sensoriese eienskappe soos groenboontjie en aspersie. Die soet rooiwyne het chemies geassosieer met sure en sensoriese terme soos soet-geassosieerd en blomagtig. Die aanvaarbaarheid van 'n kleiner groepering wyne is bepaal deur gebruik te maak van swart verbruikers in die Wes-Kaap area, Suid-Afrika. Die verbruikers het in 'n blinde proesessie onderskeie wyne se wynverpakking besigtig en aangedui of hulle die wyne sou koop. Hierdie resultate het getoon dat die verbruikers bekende kultivarwyne verkies wat 'n persepsie van waarde en styl geïllustreer het. Segmentasie tegnieke is op die data uitgevoer ten einde te bepaal of verbruikers in groepe verdeel kan word, wat betref hul voorkeur van die sensoriese of intrinsieke eienskappe van die wyne. Vier verskillende groepe is geïdentifiseer, nl. verbruikers wat 1) droë en soet rooiwyne ewe veel verkies; 2) soet rooiwyne en tot 'n mate ook droë rooiwyne verkies; 3) soet rooiwyne en tot 'n mindere mate droë rooiwyne verkies; en laastens 4) slegs droë rooiwyne verkies. Verbruikers se algemene opinies en persepsies betreffende die ekstrinsieke eienskappe van die wyne is ook ondersoek, met ander woorde faktore wat die aankoop van wyne beïnvloed. Daar is gevind dat swart verbruikers wat nie gereeld wyn drink, bekende handelsmerke verkies, terwyl verbruikers wat gereeld wyn drink, daarvan hou om hul horisonne te verbreed en te eksperimenteer met 'n verskeidenheid handelsmerke. Ekstrinsieke of nie-sensoriese aspekte soos, alkohol-inhoud, etiket, oesjaar, prys en kultivar is die belangrikste faktore wat in ag geneem word wanneer rooiwyne gekoop word, terwyl wyntoekennings en die feit dat die wyn met kurke gebotteleer word, nie as belangrik beskou word nie. Daar is ook gevind dat die meer ingeligte verbruiker, wat hoë kwaliteit wyne koop, meer van die bogenoemde aspekte in ag neem tydens die aankoopproses, terwyl die verbruiker wat meer geneig is om goedkoper wyne te koop, slegs 'n paar ekstrinsieke faktore in ag neem.

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.

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.

The quality of red wine was evaluated relating the variation of meteorological conditions such as color quantification and phenolic compound. Red wines of the cultivars Vitis vinifera, Cabernet Sauvignon, Merlot and Tannat, of the crops of 2003 and 2004 from the low-land (Santana do Livramento) or high-land (Bento Gonçalves) regions of the state of Rio Grande do Sul were analyzed. The phenolic compounds quantified were total flavonoids, anthocyanic flavonoids, non-anthocyanic flavonoids, total polyphenols, polymerized polyphenols, total anthocyanins and free anthocyanins. For the color were analyzed the color intensity and tonality and the chromatic parameters relative to the color spaces that were calculated from the tristimuli values, X, Y, and Z, based on the visible absorption spectra (400-700 nm) with 10nm of pause, on the illuminant D65 reading. The meteorological data related to the crop seasons of 2003 and 2004 were provided by 'Embrapa Uva e Vinho' (Agro meteorological station) in Bento Gonçalves and by 'Pernod Ricard' Brazil (meteorological station in Santana do Livramento). The wines of the cultivar Tannat of the crops of 2003 and 2004 has a high level of phenolic compounds, color intensity and chromatic parameters, due to the cultivar characteristics of having in its composition high level of anthocyanins, showing the red tint, while the wines of the cultivar Cabernet Sauvignon of the 2003 crop, from both regions has low level of phenolic compounds and low color intensity, showing a ruby tint. The 2004 crop in the low-land and high-land regions shows high level of phenolic compounds and color intensity, due to the climatic conditions favorable, dry, high insulation and with media temperature higher on the grapes maturation period, what provided a more complete maturation, mainly phenolic, while the 2003 crop presented a lot of precipitation and low insulation during the grapes maturation period. / Avaliou-se a qualidade dos vinhos tintos relacionando-os a variação das condições meteorológicas com a quantificação da cor e dos compostos fenólicos. Foram analisados vinhos tintos das variedades Vitis vinifera, Cabernet Sauvignon, Merlot e Tannat, das safras de 2003 e 2004 provenientes da região de Santana do Livramento (Região da Campanha) e de Bento Gonçalves (Serra gaúcha), do Rio Grande do Sul. Os compostos fenólicos quantificados foram os flavonóides totais, flavonóides antociânicos, flavonóides não-antociânicos, polifenóis totais, polifenóis polimerizados, antocianinas totais e antocianinas livres. Quanto à cor, foram analisadas a intensidade e a tonalidade bem como os parâmetros cromáticos relativos aos espaços de cor, calculados a partir de valores triestímulos X,Y,Z, com base nos comprimentos de onda de 400 a 700 nm, em intervalos de 10 nm, nas leituras do iluminante D65. Os dados das condições meteorológicas referentes às safras 2003 e 2004 foram fornecidos pela Estação Agroclimatológica da Embrapa Uva e Vinho, de Bento Gonçalves, e pela Estação Meteorológica da Pernod Ricard Brasil, de Santana do Livramento. Os vinhos da variedade Tannat, das safras de 2003 e 2004, apresentaram maior teor de compostos fenólicos, intensidade de cor e os parâmetros cromáticos, devido às características da variedade de possuírem em sua composição maiores teores de antocianinas, o que indica vinhos de tonalidade vermelha, enquanto que os vinhos da variedade Cabernet Sauvignon da safra 2003 apresentaram, nas duas regiões, menores teores de compostos fenólicos comparados com as outras variedades, com pouco valor de intensidade de cor, indicando uma tonalidade rubi. A safra de 2004, nas regiões de Bento Gonçalves e de Santana do Livramento, apresentaram um maior teor de compostos fenólicos e um elevado índice de intensidade de cor, devido às condições meteorológicas favoráveis, safra seca e ensolarada, com temperatura média do ar mais elevada no período de maturação das uvas, que proporcionaram índices de maturação, principalmente a fenólica, mais completa, enquanto que a safra de 2003 apresentou muita precipitação pluvial e pouca insolação durante o período de maturação das uvas.

Made available in DSpace on 2015-05-14T13:21:45Z (GMT). No. of bitstreams: 1 parte1.pdf: 2505729 bytes, checksum: e872a92484e063cf1f264ba7b16d9e2e (MD5) Previous issue date: 2010-03-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work proposes the use of digital images captured by a Webcam for determination of total acidity in red wines by means of an acid-base titration without using an external indicator. Digital images present the colour of the emergent radiation, which is complementary to the radiation absorbed by molecules of anthocyanines presents in wines. Each image, generated according to RGB system, yields a matrix of the values of the R, G and B components whose averages define a the colour value obtained as: 2R ⋅2G ⋅2B. This value was adopted as analytical response to build titrations curves based on digital images (DIB). For a more precise localization of the end point, titrations curves were generated on the basis of the second derivative values of the analytical response. Anthocyanines present different colours according to medium pH and, from the variation of the colour values of the images obtained during the titration of the red wines, the end point could be detected with precision. The official method recommends the use of potenciometric titration for determination of total acidity in red wines. This method requires a dilution of the sample before the titration that must be carried out until a fixed value of pH (8.2 8.4). In order to illustrate the feasibility of the proposed method titrations involving the determination of total acidity in ten red wines samples were carried out. Results were compared to the ones obtained by potenciometric titration used as reference method. No statistic difference has been observed between the results by applying the paired t-test at 95% confidence level. The proposed method yielded results with a better precision than the official method. These advantageous characteristics are attributed to the trivariate nature of the measures associated to digital images. / Neste trabalho, propõe-se o uso de imagens digitais, capturadas com uma Webcam, para determinação da acidez total de vinhos tintos por meio de titulação ácido-base sem a utilização de indicador externo. As imagens digitais apresentam a cor da radiação emergente que é complementar à da radiação absorvida por moléculas de antocianinas presentes nos vinhos. Cada imagem, gerada de acordo com o sistema vermelho-verde-azul (RGB), fornece uma matriz de valores dos componentes R, G e B cujas médias definem o valor de cor obtido como: 2R ⋅2G ⋅2B. Esse valor foi adotado como resposta analítica para a construção das curvas de titulação baseadas em imagens digitais (DIB). Para a localização mais precisa do ponto final, foram geradas as curvas de titulação com base nos valores da segunda derivada da resposta analítica. As antocianinas apresentam diferentes cores de acordo com o pH do meio e, a partir das variações do valor de cor das imagens obtidas durante a titulação dos vinhos tintos, o ponto final pôde ser detectado com precisão. O método oficial recomenda o uso da titulação potenciométrica para a determinação da acidez total de vinhos tintos. Este método requer diluição da amostra antes da titulação que deve ser efetuada até um valor fixo de pH (8,2-8,4). A fim de ilustrar a viabilidade do método proposto, foram realizadas titulações envolvendo a determinação da acidez total em dez amostras de vinhos tintos. Os resultados foram comparados com os obtidos pela titulação potenciométrica usada como método de referência. Constatou-se que não há diferença sistemática estatisticamente significativa entre os resultados, aplicando-se o teste t emparelhado ao nível de 95% de confiança. O método proposto produziu resultados com uma precisão melhor que a do método oficial. Essas características vantajosas da titulação DIB são atribuídas à natureza trivariada das medidas associadas às imagens digitais.

La famille aromatique du végétal dans les vins rouges recouvre une large diversité de nuances. Nos travaux révèlent que celles-ci n’ont pas toujours de lien direct avec les composés connus (2-méthoxy-3-alkylpyrazines, alcools en C6). Aussi, après avoir été définis sensoriellement, les déterminants moléculaires de cette famille d’odeurs ont été recherchés en s’appuyant, à partir de vins représentatifs, sur différentes techniques de fractionnement (CLHP, distillation sous vide) puis MDCPG-O-SM. Une première origine de ces nuances a été développée, celle associée à la maturité des raisins. La présence du 1,8-cinéole (eucalyptol), avec des notes « vertes », selon une origine variétale en lien avec la maturité des raisins a pu être attestée dans les vins de Cabernet Sauvignon. La capacité d’un cépage à en produire des quantités significatives (Fer Servadou) ainsi qu’une origine exogène associée à la présence d’une espèce d’armoise au vignoble (Artemisia verlotiorum) sont aussi établis. Une autre origine d’apparition des nuances végétales a été considérée : le pressurage des marcs. Cette étude montre le lien étroit entre la catégorie aromatique des vins de presse et la famille du végétal. En outre, elle révèle la présence de divers marqueurs odoriférants, en particulier le (Z)-4-heptenol dont l’évolution est corrélée au niveau de pression et la contribution sensorielle établie, à l’inverse de la plupart des alcools en C6 ; de même qu’elle suggère l’implication de plusieurs composés carbonylés à l’odeur caractéristique des vins de presse. L’influence des paramètres technologiques (inertage, pression, SO2, FML) est aussi précisée. La présence du salicylate de méthyle comme marqueur de défense de la plante contre plusieurs maladies cryptogamiques (mildiou, black rot, esca) et comme contributeur à l’odeur végétale de certains vins rouges a enfin pu être démontrée. / The green aromas family includes in red wines a large diversity of nuances. First, this study revealed that these nuances are not directly related to known compounds (e.g. 2-méthoxy-3-alkylpyrazines, C6 alcohols). After a sensory definition, the molecular determinants of these aroma nuances were investigated based on fractionation strategies including HPLC and vacuum distillation then MDGC-O-MS. A first source of nuances associated with grapes ripeness was developed. The presence of 1,8-cineole (eucalyptol) with a varietal origin was evidenced in Cabernet Sauvignon wines. The ability of a grape variety to produce significant amounts (Fer Servadou) and an exogenous origin associated with the presence of Artemisia species in vineyards (Artemisia verlotiorum) were also highlighted. Another origin, related to the pressing of grape marc was then considered. This study shown the connection between the aromatic category of press wines and the green aromas. Furthermore, it revealed the presence of odoriferous molecules including (Z)-4-heptenol, with a sensory contribution, associated to the increase of pressure in the press tank, but not for the majority of C6 alcohols. It also suggested the involvement of several carbonyl compounds in the characteristic odor of press wines. The influence of technological parameters (without oxygen, pressure, SO2, malolactic fermentation) was also specified. Finally, this study revealed the presence of methyl salicylate as a plant defense marker against several fungal diseases (downy mildew, black rot, esca) and as a contributor to fresh green aromas of certain red wines.