In the Rio Grande do Sul State, grape production is an already consolidated activity of significant socio-economic importance, accounting for about 90% of national production of grapes, wines and derivatives. In this sense, wine is an important product because of the added values transferred to the wineries and grape growers. There are five major wine regions within Rio Grande do Sul: Serra do Nordeste, Campanha, Serra do Sudeste, Central and Campos de Cima da Serra. Cabernet Sauvignon is the State's most important Vitis vinifera variety. The wine of this variety is world famous for its varietal character, intense color, richness in tannins and for its complexity of aroma and bouquet. Color is a key indicator of quality wines. It contributes to achieving the highest ratings and effectively the highest prices, and is directly related to quality of the raw material used. The objective methods of color evaluation are the fastest and, moreover, are replicable and not subject to subjective errors, so are of fundamental importance for the wine industry. The samples of red wines for this study, from the five wine regions of Rio Grande do Sul, were obtained in collaboration with the Instituto Brasileiro do Vinho (IBRAVIN) and analyzed at the Departamento de Tecnologia e Ciência de Alimentos of the Universidade Federal de Santa Maria. The following chromatic characteristics were analyzed: CIEL*a*b coordinates *L, *a and *b, cylindrical coordinates H* (hue angle) and C* (chroma), color intensity, hue and percentages of yellow, red and blue. Physicochemical parameters alcohol content, total acidity, pH, total phenolics content and anthocyanins were also determined. The wines from the Central region had the highest values of hue angle H* and the highest average of lightness. Samples from the Campanha region were characterized by the lowest average of hue. The wines from the Serra do Nordeste region were those with the highest average of croma, anthocyanins and total phenolics content. All wines were in accordance with Brazilian legislation for total acidity. However, pH values were high (near 4.0), which favors the development of bacteria. By the analysis of the results obtained in the chromatic and physical-chemical properties of the samples, it was possible to establish a comparison between Cabernet Sauvignon wines produced in Rio Grande do Sul, in different seasons and different wine regions, to support the quest for quality improvement in production of fine wines in the state. / No Estado do Rio Grande do Sul a produção de uvas é uma atividade já consolidada, de significativa importância socioeconômica, responsável por cerca de 90% da produção nacional de uvas, vinhos e derivados. Neste sentido, o vinho é um importante produto devido ao valor agregado que transfere para as vinícolas e para os produtores de uvas. São cinco as principais regiões vitivinícolas do Rio Grande do Sul: Serra do Nordeste, Campanha, Serra do Sudeste, Região Central e Campos de Cima da Serra. A cultivar Cabernet Sauvignon é a principal variedade Vitis vinifera do Estado. O vinho desta casta é mundialmente conhecido pelo seu caráter varietal, com intensa coloração, riqueza em taninos e complexidade de aroma e buquê. A cor compõe um dos principais indicadores da qualidade de vinhos, além de colaborar para alcançar as melhores classificações e efetivamente os maiores preços, relacionando-se diretamente com a qualidade da matéria-prima. Os métodos objetivos de avaliação da cor são os mais rápidos e, além disso, reproduzíveis e não sujeitos a erros subjetivos, logo são de fundamental importância para a indústria vinícola. As amostras de vinhos tintos Cabernet Sauvignon para este trabalho, provenientes das cinco regiões vitivinícolas do Rio Grande do Sul, foram obtidas com a colaboração do Instituto Brasileiro do Vinho (IBRAVIN) e analisadas no Departamento de Tecnologia e Ciência de Alimentos da Universidade Federal de Santa Maria. Foram analisadas as características cromáticas através das coordenadas cromáticas L*, a* e b* do Espaço CIE L*a*b*, das coordenadas cilíndricas H* (ângulo de tonalidade) e C* (Croma), bem como a quantificação dos índices de intensidade de cor, tonalidade e os percentuais das componentes amarela, vermelha e azul. Também foram determinados os parâmetros físico-químicos graduação alcoólica, acidez total, pH, conteúdo de antocianinas e compostos fenólicos totais. Os vinhos da Região Central apresentaram os maiores valores do ângulo de tonalidade H* e a maior luminosidade média. As amostras da Região da Campanha caracterizaram-se pela menor média de tonalidade. Já os vinhos da Região da Serra do Nordeste foram os que apresentaram as maiores médias de Croma, a maior média de antocianinas totais e também a maior média de índice de polifenóis totais. Quanto à acidez total, todos os vinhos analisados estavam em conformidade com a legislação brasileira, porém os valores de pH se apresentaram elevados (próximos de 4,0), situação que favorece o desenvolvimento de bactérias. Portanto, através dos resultados obtidos nas análises cromáticas e físico-químicas das amostras, foi possível estabelecer um comparativo entre vinhos Cabernet Sauvignon produzidos no Rio Grande do Sul, de diferentes safras e diferentes regiões vitivinícolas, no sentido de subsidiar a busca pelo aprimoramento da qualidade na produção de vinhos finos no estado.

Orientador: Maria Regina Bueno Franco / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-05T19:08:05Z (GMT). No. of bitstreams: 1 Santos_BetaniaAraujoCosmedos_D.pdf: 3332145 bytes, checksum: a5f2c537c582a4aff99c0c55902993f7 (MD5) Previous issue date: 2006 / Resumo: Apesar da importância do aroma e sabor para determinar a qualidade dos vinhos, praticamente não existe nenhum estudo sobre a composição de voláteis dos vinhos nacionais. Os poucos que existem utilizam ainda coluna empacotada e outros traçam apenas o perfil sensorial dos vinhos, sem fazer correlações dos dados com qualquer outro parâmetro. No presente trabalho estudou-se 11 vinhos seco varietal Cabernet Sauvignon oriundos das principais regiões produtoras do país: Serra Gaúcha e Campanha, no Rio Grande do Sul; do Vale do Rio do Peixe, em Santa Catarina e do Vale do São Francisco, região de Pernambuco/Bahia. Foram efetuadas análises dos constituintes químicos e minerais presentes, após a homogeneização de três garrafas de vinho. Os parâmetros físico-químicos foram determinados pelos métodos clássicos e os teores dos minerais cálcio, magnésio, ferro, cobre e zinco foram analisados por absorção atômica; potássio, lítio, sódio e rubídio por emissão de chama e o fósforo por colorimetria. As características sensoriais das amostras foram determinadas pelo uso da Análise Descritiva Quantitativa através de nove provadores selecionados e treinados. As amostras foram avaliadas em quintuplicata, em 11 sessões, utilizando blocos incompletos balanceados. O teste de aceitação também foi realizado e os dados avaliados utlizando-se o Mapa Interno de Preferência. Os componentes voláteis foram extraídos em triplicata de cada garrafa de vinho, através de uma técnica de extração em fase sólida utilizando coluna Lichrolut EN e eluíção com diclorometano, conforme metodologia já validada para análise de compostos voláteis em vinho. Os contituinte voláteis foram separados por duas colunas capilares de polaridades diferentes. A identificação dos voláteis foi realizada por espectrometria de massas, além da comparação dos índices de Kovats experimentais com os valores encontrados na literatura e comparação dos espectros dos compostos com os dos padrões disponíveis. O extrato da amostra de maior aceitação foi analisado pela técnica de cromatografia gasosa-olfatometria0 para identificar a contribuição dos diferentes compostos voláteis para o aroma global do vinho. Os resultados das análises físico-químicas mostraram que todos os vinhos estavam dentro dos padrões estabelecidos pela legislação vigente, sendo que os teores encontrados de acidez volátil foram considerados elevados. Os valores de pH também foram elevados, mas tal fato é esperado quando da avaliação de vinhos Cabernet Sauvignon. A análise de minerais mostrou que os teores de potássio estavam bem acima dos encontrados em literatura. A técnica estatística multivariada de Análise de Componentes Principais, aplicada ao teor dos componentes físico-químicos e dos minerais não foi capaz de discriminar as amostras em relação à sua origem geográfica. O emprego do Mapa Interno de Preferência demonstrou que a amostra 245 (Serra Gaúcha) foi a mais aceita pela equipe, sendo caracterizada por uma forte sensação de doçura, apesar do teor de açúcares (2,65±0,05 g/L), aroma frutado e de frutas vermelhas. Os vinhos da região nordeste obtiveram uma aceitação inferior junto aos consumidores, juntamente com a amostra 512 (Serra Gaúcha). Foram identificados pela primeira vez em vinhos nacionais, 39 compostos voláteis, sendo que 13 pertenciam à classe dos álcoois, 13 à dos ésteres, 7 à dos ácidos, 2 à das lactonas, além de 3 compostos carbonílicos e 1 composto fenólico. Apesar da variação da concentração dos compostos entre as amostras, o pico correspondente aos compostos 2-metil-1-butanol e 3-metil-1-butanol foi o mais abundante para todas as amostras, seguido pelo álcool feniletílico, lactato de etila e álcool isobutírico. A amostra 245 (Serra Gaúcha), que obteve a melhor aceitação, distinguiu-se das amostras 326 e 512 (Serra Gaúcha), de menor aceitação, pela alta concentração de acetato de etila, 1-butanol, 2-metil-1-butanol concomitantemente com o 3-metil-1-butanol, hexanoato de etila, 3-metil-1-pentanol, octanoato de etila e ácido hexanóico. Uma análise olfatométrica preliminar permitiu a detecção dos compostos voláteis odoríferos presentes na amostra de maior aceitação, além de estabelecer sua contribuição para o aroma total. Acetato de feniletila, furfural, hexanoato de etila, ácido hexanóico e butírico, além de um composto não identificado foram considerados importantes para o aroma do vinho estudado / Abstract: Despite the importance of flavour in determining the sensorial quality of wines, there are only few studies concerning the volatile composition of Brazilian wines. These few studies reported only major compounds, utilizing packed columns while other researchers described only the sensorial profile of the wines, without establishing any correlation of the data with other parameters. In the present study, 11 Cabernet Sauvignon red wines from main regions of the country were analysed: Rio Grande do Sul (Serra Gaúcha and Campanha); Santa Catarina (Rio do Peixe valley) and Pernambuco/Bahia (Rio São Francisco valley). Physical-chemical parameters were determined by classic analysis and the minerals content was determined by flame absorption and flame emission methods, after homogenization of 3 wine bottles. Nine selected and trained judges, utilizing Quantitative Descriptive Analysis, determined the samples¿ sensorial characteristics. They were evaluated in fiveplicates through 11 sessions. The acceptance test was realized with 87 consumers participation and data were interpreted utilizing Internal Preference Mapping (MDPREF). The volatile compounds were extracted in triplicates from each wine bottle and Total Analysis technique was used. A Lichrolut EN cartridge was utilized and elution with dichloromethane was performed, according to an already recognized in the literature methodology for volatile compounds analysis in wine. The volatile mixture of compounds was separated by high-resolution gas chromatography, utilizing two columns with different polarity phases. The identification of volatile compounds was realized by using mass spectrometer coupled to gas chromatography, besides comparison of Kovats experimental indexes with literature values and beyond that comparison between spectral mass data of the unknowns and those of the standards. A preliminary olfatometric test was realized using two selected and trained judges, who evaluated aroma of the eluted compounds of the highest preferred sample. Results of the physical-chemical and mineral analyses indicated that all samples were within the established legal limits. The amount of volatile acids was considered high, but such a fact is expected when Cabernet Sauvignon wines are evaluated. Potassium content of the samples was higher than already reported values in literature. The use of the MDPREF demonstrated that sample 245 was the highest preferred wine, characterized by a strong perception of the sweet, fruity and red fruit aroma descriptors. The northeast wines and sample 512 obtained the lowest acceptance among consumers. Thirty-nine volatile compounds were identified by GC-MS and Kovats Indexes in Brazilian wines by the first time, of which 13 were alcohols, 13 esters, 7 acids, 2 lactones, 2 terpenes, 3 carbonyl compounds and a phenolic compound. In spite of the great variation observed among the samples, 3-methyl butanol and 2-methyl butanol peaks were the most abundant compounds, followed by phenylethyl alcohol, ethyl lactate and isobutyric acid. The previous olfatometric test applied to the extract of the most preferred wine leaded to the detection of the odoriferous volatile compounds responsible for their acceptance while determining the contribution of those compounds to the global aroma. Hexanoic acid, furfural, butanoic acid and ethyl hexanoate were considered important contributors to the aroma of this preferred sample. ACP applied to physical-chemical and mineral content of the samples was not able to discriminate different samples according to their geographical origin / Doutorado / Doutor em Ciência de Alimentos

Thesis (PhD(Agric))--Stellenbosch University, 2014. / ENGLISH ABSTRACT: This study focussed on the effect of oxygen on the chemical and sensory evolution of Sauvignon blanc wine under controlled oxidation conditions. The sensorial interactive effects between Sauvignon blanc varietal aroma compounds and compounds that typically arise during oxidation of white wines were also investigated. In the first research chapter the sensorial interactive effects of Sauvignon blanc impact compounds with aldehydes typically originating from oxidation of white wines were investigated. Four compounds, 3‐ mercaptohexan‐1‐ol (3MH), 3‐isobutyl‐2‐methoxypyrazine (IBMP), 3‐(methylthio)‐propionaldehyde (methional) and phenylacetaldehyde were added together in a model wine medium at varying concentrations. The concentrations chosen were according to those reported in literature to occur in Sauvignon blanc wines. The sensory effects of these compounds were profiled using a trained sensory panel. Compounds were first profiled individually and results showed that the change in comcpound concentration not only led to a change in intensity ratings but also in some cases a change in the descriptor. All four compounds in the same sample showed complicated interactive effects. Data were statistically analysed using relatively novel techniques such as statistical networks that allowed deeper insights into the interactions involved. Various observations were made such as the contribution of 3MH to the ‘green’ character of the wine, the potent suppressing abilities of methional on 3MH and IBMP and the additive effect of methional and IBMP contributing to the ‘cooked’ character of the sample. In the second research chapter the effect of repetitive oxidation on a fresh and fruity style Sauvignon blanc wine was investigated. Results showed the progress and evolution of aromatic and non‐aromatic compounds during an oxidative aging period. A large range of chemical analyses were conducted together with extensive sensory profiling. Results showed a decrease in volatile thiols responsible for the fruity nuances and an increase in oxidation‐related compounds, such as acetaldehyde, during the course of the oxidation. Sensory profiling showed the evolution of the wine aroma during oxidation. The wine evolved from a fresh and fruity wine to slight oxidation and then developed extreme oxidative characteristics. The Control samples (no oxygen added) developed a ‘cooked’ character which could indicate the formation of reductive compounds in these wines. Conversely, the wines that received a single dose of oxygen did not develop this flavour and were perceived to be more fresh and fruity than the Control samples. The evolution of the wine colour was also monitored using a spectrophotometer as well as a sensory panel and results suggest that the colour of the wine evolved before the disappearance of the pleasant aroma. The advantages and disadvantages of oxygen exposure to this type of wine style are discussed as well as the complexity of the wine matrix and sensory interactions occurring in the specific wine. The aim of the third research chapter was again to investigate further sensory interactions between Sauvignon blanc varietal aroma compounds and an oxidation‐related compound. After the observations reported in the second research chapter, the inclusion of acetaldehyde in an interaction study seemed to be of critical importance. Acetaldehyde can reach significant concentrations during oxidation and can have a detrimental effect on wine aroma. This interaction study included three compounds, 3MH, IBMP and acetaldehyde. Acetaldehyde was able to effectively mask the ‘green’ character of the sample, while it also enhanced certain fruity nuances when present at specific concentrations. 3MH was able to suppress the oxidising character of acetaldehyde when present at sufficient concentrations. The results from this study clearly showed the complexity of the wine medium and the interactions involved. It also highlighted the importance of performing these types of sensory studies in a simple medium opposed to a complex matrix such as wine. The effect of oxygen on various aspects of the wine was investigated and the combination of chemical and sensory data delivered some interesting conclusions also involving interactions that occurred. This study paved the way for future investigations on the sensory relationships of Sauvignon blanc aroma compounds and the role of proper oxygen management in the production of quality wines. / AFRIKAANSE OPSOMMING: Die doelwit van die studie was om die effek van gekontroleerde oksidasie op die ontwikkeling en verloop van verskeie chemiese komponente asook die ontwikkeling van die sensoriese profiel van ‘n Sauvignon blanc wyn te ondersoek. Bykomende studies ondersoek die interaksie/wisselwerking tussen aromakomponente in ‘n eenvoudige matriks. Interaksies tussen spesifieke Sauvignon blanc kultivargeassosieerde aromakomponente en komponente wat normaalweg tydens die oksidasie van witwyne ontwikkel, word ondersoek. Die eerste navorsingshoofstuk het ten doel om die interaksie tussen tipiese Sauvignon blanc aromakomponente (of impakkomponente) met aldehiede wat normaalweg tydens oksidasie van witwyne ontwikkel, na te vors. Vier komponente is in ‘n modelwyn gevoeg teen verskeie konsentrasies, wat oor die algemeen in die literatuur gerapporteer is om voor the kom in Sauvignon blanc wyne. Die komponente wat ondersoek is, is: 3‐merkaptoheksanol (3MH), 3‐isobutiel‐2‐metoksiepirasien (IBMP), 3‐ (metieltio)‐propionaldehied (methional) en fenielasetaldehied. Die sensoriese effekte van die komponente is deur ‘n opgeleide sensoriese paneel geëvalueer. Komponente is eers individueel geanaliseer en die resultate het getoon dat dat die intensiteit van die spesifieke aroma verander namate die konsentrasie verander. In sommige gevalle het die beskrywende woord vir die aroma ook verander. Deur al vier komponente in dieselfde monster te voeg word die ondersoek gekompliseer. Die data is statisties geanaliseer deur gebruik te maak van relatiewe nuwe tegnieke soos statistiese netwerke wat dieper insig in die betrokke interaksies bewerkstellig. Verskeie waarnemings word gerapporteer onder andere die bydrae van 3MH tot die ‘groen’ karakter van die wyn, die kragtige onderdrukkingsvermoë van methional op 3MH en IBMP asook die opbouende effek van methional en IBMP wat bydra tot die ‘gekookte’ karakter van die monster. Die tweede navorsingshoofstuk is daarop gemik om die effek van herhalende oksidasie op 'n vars en vrugtige styl Sauvignon blanc wyn te ondersoek en om die vordering en ontwikkeling van aromatiese en nie‐aromatiese komponente gedurende hierdie tydperk te analiseer. ‘n Wye reeks chemiese komponente is geanaliseer tesame met omvangryke sensoriese analise. ‘n Afname in die vlugtige tiole, wat verantwoordelik is vir die vrugtige geure, is gevind tesame met ‘n toename in oksidasie‐verwante komponente (soos asetaldehied). Sensoriese ondersoeke toon ook die evolusie van die wynaroma tydens oksidasie. Die wyn het ontwikkel van ‘n vars en vrugtige styl na effense oksidasiegeure waarna ekstreme oksidasiekarakters waargeneem is. Die Kontrole monsters het ‘n ‘gekookte’ karakter ontwikkel wat ‘n aanduiding van die ontwikkeling van ‘reduktiewe’ komponente in hierdie wyn kan wees. Aan die ander kant het wyne wat een suurstofdosering ontvang het, geen van hierdie geure ontwikkel nie en die wyn is as varser en vrugtiger beskryf in vergelyking met die Kontrole monsters. Die ontwikkeling van die wynkleur is ook gemonitor deur gebruik te maak van ‘n spektrofotometer asook 'n sensoriese paneel. Resultate stel voor dat die kleur van die wyn ontwikkel voor die aangename geure begin verdwyn. Die voor‐ en nadele van suurstofblootstelling aan hierdie tipe wynstyl word bespreek asook die kompleksiteit van die wynmatriks en sensoriese interaksies wat in hierdie spesifieke wyn voorkom. Die derde navorsingshoofstuk is weereens daarop gemik om die sensoriese interaksie tussen tipiese Sauvignon blanc kultivar‐geassosieerde aromakomponente en nog ‘n oksidasie‐geassosierde aromakomponent te ondersoek. Die resultate vanuit die tweede navorsingshoofstuk het die insluiting van asetaldehied in die interaksiestudie genoodsaak. Asetaldehied kan betekenisvolle konsentrasies tydens oksidasie behaal en kan ook nadelige effekte op wynaroma hê. Hierdie interaksiestudie het die volgende drie komponente ingesluit: 3MH, IBMP en asetaldehied. Asetaldehied het die ‘groen’ karakter van IBMP effektief gemaskeer terwyl dit die waarneming van die vrugtige aroma ondersteun en selfs verhoog het wanneer dit teen sekere konsentrasies teenwoordig was. 3‐Merkaptoheksanol het die oksidasiekarakter van asetaldehied onderdruk wanneer dit teen genoegsame konsentrasies teenwoordig was. Die kompleksiteit van wyn as ‘n navorsingsmedium is duidelik vanuit die studie veral in die ondersoeking van interaksie‐effekte tussen komponente. Die belangrikheid van die gebruik van 'n eenvoudige medium teenoor ‘n komplekse medium vir soortgelyke studies is dus duidelik. Die effek van suurstof op verskeie aspekte van witwyn is ondersoek en die kombinasie van chemiese en sensoriese data het interessante gevolgtrekkings gelewer. Die studie het die pad vir toekomstige studies gebaan in terme van sensoriese interaksies met betrekking tot Sauvignon blanc aroma. Die belangrikheid van oordeelkundige suurstofbestuur tydens die produksie van kwaliteit wyne is ook uitgelig.

Thesis (PhD--Biological Sciences)--University of Auckland, 2010. / Includes bibliographical references.

Thesis (M. Appl. Sc.) -- Lincoln University, 2009. / Also available via the World Wide Web.

Machine harvesting is the most widely expanded vineyard mechanization practices today. Foreign research into the effects of mechanization demonstrated that the grape quality was unaffected, in some cases, improved with the introduction of machine harvesting. In 2015 within the framework of this diploma work the experiment was performed by Sauvignon blanc. All data were subjected to Analysis of variance at P < 0,05. Although statistical differences were found in the grapes by total acidity and type of harvesting, statistical differences were not found in wine. Wine produced from machine grape harvesting were more fruity in sensory analysis.

A ocratoxina (OTA) é uma micotoxina que possui propriedades nefrotóxicas, hepatotóxicas, teratogênicas e carcinogênicas. No Brasil, o limite máximo permitido de OTA em vinhos foi estabelecido em 2011 e é 2 μg/L. A ocorrência desta toxina em vinhos está relacionada principalmente à presença de fungos do gênero Aspergillus nas uvas usadas para a vinificação. Deste modo, o objetivo deste estudo foi verificar a influência das etapas de elaboração de vinho Cabernet Sauvignon sobre os níveis de OTA, através de dois diferentes experimentos: (A) vinho elaborado a partir de uvas inoculadas com fungo ocratoxigênico e (B) vinho elaborado com uvas naturalmente contaminadas com OTA. Para os dois experimentos, amostras das etapas mosto, fermentação/maceração, descuba, pós-fermentação, trasfega e maturação foram coletadas em triplicata, durante um período de 5 meses. A OTA foi detectada através da técnica de cromatografia líquida de alta eficiência com detector de fluorescência (CLAE-FL) e o limite de detecção e quantificação foi de 0,06 μg/L e 0,6 μg/L, respectivamente. Durante a vinificação, as etapas que apresentaram maior percentual de redução da toxina foram descuba, pós-fermentação e trasfega. Reduções significativas nos níveis de OTA foram observadas após a conclusão da vinificação. No vinho elaborado com uvas inoculadas com fungo ocratoxigênico observou-se uma redução de 92,6%. Valor similar (92%) foi verificado no vinho produzido com uvas naturalmente contaminadas por OTA. Considerando todo o processo de vinificação, pode-se sugerir que a diminuição dos níveis de OTA foi observada principalmente, devido à adsorção da toxina à parede celular das leveduras. Além disso, a adsorção da toxina aos sólidos em suspensão presentes no vinho durante a elaboração pode ter ocorrido. / The ochratoxin A (OTA) is a mycotoxin with nephrotoxic, hepatotoxic, teratogenic and carcinogenic properties. In Brazil, the permitted maximum limits for the OTA in wines was established in 2011 and is 2 μg/L. The occurence of this toxin in wines is due mainly for presence of fungi from Aspergillus genera in grapes used for winemaking. In this way, the aim of this study was to check the influence of stages of the winemaking process of Cabernet Sauvignon grape on the OTA levels through two different experiments: (A) wine made from grapes inoculated with ochratoxigenic fungi and (B) wine made from grapes naturally contaminated with OTA. For the two experiments, samples of must, fermentation/maceration, drawn-off wine, after fermentation, racking and maturation stages were collected in triplicate, during 5 months. The OTA was detected using high-performance liquid chromatography with fluorecence detector (HPLC-FL) and the limit of detection and limit of quantitation were 0.06 and 0.6 μg/L, respectively. During the winemaking, the stages that show higher toxin reduction were drawn-off wine, after alcoholic fermentation and racking. Significant reductions in OTA levels were observed when winemaking was finished. A reduction of 92.6% was observed in wine made from grapes inoculated with ochratoxigenic fungi. Similar value (92%) was verified in wine made from grapes naturally contaminated with OTA. Considering all winemaking process, we may suggest that the decreasing of OTA levels was observed mainly due to adsorption of the toxin in cell wall of yeast. Furthermore, the adsorption of the toxin in suspended solids present in wine during the winemaking may be occurred.

A ocratoxina (OTA) é uma micotoxina que possui propriedades nefrotóxicas, hepatotóxicas, teratogênicas e carcinogênicas. No Brasil, o limite máximo permitido de OTA em vinhos foi estabelecido em 2011 e é 2 μg/L. A ocorrência desta toxina em vinhos está relacionada principalmente à presença de fungos do gênero Aspergillus nas uvas usadas para a vinificação. Deste modo, o objetivo deste estudo foi verificar a influência das etapas de elaboração de vinho Cabernet Sauvignon sobre os níveis de OTA, através de dois diferentes experimentos: (A) vinho elaborado a partir de uvas inoculadas com fungo ocratoxigênico e (B) vinho elaborado com uvas naturalmente contaminadas com OTA. Para os dois experimentos, amostras das etapas mosto, fermentação/maceração, descuba, pós-fermentação, trasfega e maturação foram coletadas em triplicata, durante um período de 5 meses. A OTA foi detectada através da técnica de cromatografia líquida de alta eficiência com detector de fluorescência (CLAE-FL) e o limite de detecção e quantificação foi de 0,06 μg/L e 0,6 μg/L, respectivamente. Durante a vinificação, as etapas que apresentaram maior percentual de redução da toxina foram descuba, pós-fermentação e trasfega. Reduções significativas nos níveis de OTA foram observadas após a conclusão da vinificação. No vinho elaborado com uvas inoculadas com fungo ocratoxigênico observou-se uma redução de 92,6%. Valor similar (92%) foi verificado no vinho produzido com uvas naturalmente contaminadas por OTA. Considerando todo o processo de vinificação, pode-se sugerir que a diminuição dos níveis de OTA foi observada principalmente, devido à adsorção da toxina à parede celular das leveduras. Além disso, a adsorção da toxina aos sólidos em suspensão presentes no vinho durante a elaboração pode ter ocorrido. / The ochratoxin A (OTA) is a mycotoxin with nephrotoxic, hepatotoxic, teratogenic and carcinogenic properties. In Brazil, the permitted maximum limits for the OTA in wines was established in 2011 and is 2 μg/L. The occurence of this toxin in wines is due mainly for presence of fungi from Aspergillus genera in grapes used for winemaking. In this way, the aim of this study was to check the influence of stages of the winemaking process of Cabernet Sauvignon grape on the OTA levels through two different experiments: (A) wine made from grapes inoculated with ochratoxigenic fungi and (B) wine made from grapes naturally contaminated with OTA. For the two experiments, samples of must, fermentation/maceration, drawn-off wine, after fermentation, racking and maturation stages were collected in triplicate, during 5 months. The OTA was detected using high-performance liquid chromatography with fluorecence detector (HPLC-FL) and the limit of detection and limit of quantitation were 0.06 and 0.6 μg/L, respectively. During the winemaking, the stages that show higher toxin reduction were drawn-off wine, after alcoholic fermentation and racking. Significant reductions in OTA levels were observed when winemaking was finished. A reduction of 92.6% was observed in wine made from grapes inoculated with ochratoxigenic fungi. Similar value (92%) was verified in wine made from grapes naturally contaminated with OTA. Considering all winemaking process, we may suggest that the decreasing of OTA levels was observed mainly due to adsorption of the toxin in cell wall of yeast. Furthermore, the adsorption of the toxin in suspended solids present in wine during the winemaking may be occurred.

A ocratoxina (OTA) é uma micotoxina que possui propriedades nefrotóxicas, hepatotóxicas, teratogênicas e carcinogênicas. No Brasil, o limite máximo permitido de OTA em vinhos foi estabelecido em 2011 e é 2 μg/L. A ocorrência desta toxina em vinhos está relacionada principalmente à presença de fungos do gênero Aspergillus nas uvas usadas para a vinificação. Deste modo, o objetivo deste estudo foi verificar a influência das etapas de elaboração de vinho Cabernet Sauvignon sobre os níveis de OTA, através de dois diferentes experimentos: (A) vinho elaborado a partir de uvas inoculadas com fungo ocratoxigênico e (B) vinho elaborado com uvas naturalmente contaminadas com OTA. Para os dois experimentos, amostras das etapas mosto, fermentação/maceração, descuba, pós-fermentação, trasfega e maturação foram coletadas em triplicata, durante um período de 5 meses. A OTA foi detectada através da técnica de cromatografia líquida de alta eficiência com detector de fluorescência (CLAE-FL) e o limite de detecção e quantificação foi de 0,06 μg/L e 0,6 μg/L, respectivamente. Durante a vinificação, as etapas que apresentaram maior percentual de redução da toxina foram descuba, pós-fermentação e trasfega. Reduções significativas nos níveis de OTA foram observadas após a conclusão da vinificação. No vinho elaborado com uvas inoculadas com fungo ocratoxigênico observou-se uma redução de 92,6%. Valor similar (92%) foi verificado no vinho produzido com uvas naturalmente contaminadas por OTA. Considerando todo o processo de vinificação, pode-se sugerir que a diminuição dos níveis de OTA foi observada principalmente, devido à adsorção da toxina à parede celular das leveduras. Além disso, a adsorção da toxina aos sólidos em suspensão presentes no vinho durante a elaboração pode ter ocorrido. / The ochratoxin A (OTA) is a mycotoxin with nephrotoxic, hepatotoxic, teratogenic and carcinogenic properties. In Brazil, the permitted maximum limits for the OTA in wines was established in 2011 and is 2 μg/L. The occurence of this toxin in wines is due mainly for presence of fungi from Aspergillus genera in grapes used for winemaking. In this way, the aim of this study was to check the influence of stages of the winemaking process of Cabernet Sauvignon grape on the OTA levels through two different experiments: (A) wine made from grapes inoculated with ochratoxigenic fungi and (B) wine made from grapes naturally contaminated with OTA. For the two experiments, samples of must, fermentation/maceration, drawn-off wine, after fermentation, racking and maturation stages were collected in triplicate, during 5 months. The OTA was detected using high-performance liquid chromatography with fluorecence detector (HPLC-FL) and the limit of detection and limit of quantitation were 0.06 and 0.6 μg/L, respectively. During the winemaking, the stages that show higher toxin reduction were drawn-off wine, after alcoholic fermentation and racking. Significant reductions in OTA levels were observed when winemaking was finished. A reduction of 92.6% was observed in wine made from grapes inoculated with ochratoxigenic fungi. Similar value (92%) was verified in wine made from grapes naturally contaminated with OTA. Considering all winemaking process, we may suggest that the decreasing of OTA levels was observed mainly due to adsorption of the toxin in cell wall of yeast. Furthermore, the adsorption of the toxin in suspended solids present in wine during the winemaking may be occurred.

Cabernet sauvignon is the most widely planted red wine grape in California and is valued in the hundreds of millions of dollars. Cabernet sauvignon grapes, when severely vigorous or overcropped, can contain vegetal aromas and flavors when harvested. 3-alkyl-methoxypyrazines are the volatile compounds responsible for this effect and can lower the perceived quality of the wine. Resveratrol is a phytoalexin that has many medical and health benefits and can be found in red wines. An experiment was conducted in Paso Robles, CA to assess the effects of five yield levels, manipulated through cluster thinning, on methoxypyrazine and resveratrol concentrations. Berry weights and chemistry were also measured, in the form of ºBrix, pH, and TA. In 2009 and 2010, no significant statistical differences were found in methoxypyrazines in the harvested grapes. In 2009, resveratrol concentrations were below the detection limits in the wine produced. In 2010, berry weight and chemistry measurements were not significantly different, except for grapes from lightly- and greatly-thinned vines which varied in pH at harvest. The 2009 wines were subjected to discrimination and preference testing by trained tasters. No significant difference was found in the discrimination test and no difference was found using the Friedman and Kramer’s Rank test for the preference test. Only a very slight difference was found between the wines made from unthinned and greatly-thinned vines according to Tukey’s Multiple Comparison Test. The findings of this thesis suggest that cluster thinning does not affect methoxypyrazine and resveratrol concentrations or sensory analysis in Cabernet sauvignon grown on the east side of Paso Roble, CA.