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Vitis vinifera is one of the most widespread grapevines around the world representing the raw material for high quality wine production. The availability of more resistant interspecific hybrid vine varieties, developed from crosses between Vitis vinifera and other Vitis species, has generated much interest, also due to the low environmental effect of production. However, hybrid grape wine composition and varietal differences between interspecific hybrids have not been well defined, particularly for the simple phenols profile. The dynamic of these phenols in wines, where the glycosylated forms can be transformed into the free ones during winemaking, also raises an increasing health interest by their role as antoxidants in wine consumers. In this work an on-line SPE clean-up device, to reduce matrix interference, was combined with ultra-high liquid chromatography-high resolution mass spectrometry in order to increase understanding of the phenolic composition of hybrid grape varieties. Specifically, the phenolic composition of 4 hybrid grape varieties (red, Cabernet Cantor and Prior; white, Muscaris and Solaris) and 2 European grape varieties (red, Merlot; white, Chardonnay) was investigated, focusing on free and glycosidically bound simple phenols and considering compound distribution in pulp, skin, seeds and wine. Using a targeted approach 53 free simple phenols and 7 glycosidic precursors were quantified with quantification limits ranging from 0.001 to 2mgKg-1 and calibration R2 of 0.99 for over 86% of compounds. The untargeted approach made it possible to tentatively identify 79 glycosylated precursors of selected free simple phenols in the form of -hexoside (N=30), -pentoside (21), -hexoside-hexoside (17), -hexoside-pentoside (4), -pentoside-hexoside (5) and -pentoside-pentoside (2) derivatives on the basis of accurate mass, isotopic pattern and MS/MS fragmentation.

Grape pomace is a winemaking by-product that can be used to extract oenological tannins. Recently, some grape skin tannins were shown to contain very high amounts of two polyfunctional thiol precursors (3-S-glutathionylhexan-1-ol, 3-S-cysteinylhexan-1-ol) whose free forms are responsible for appreciated tropical-like flavours. This study shows that an oxidative treatment (no SO2) of white grape pomace and the presence of grape leaves and stems can increase the content of the above mentioned precursors. Moreover, it shows significant differences between Sauvignon Blanc, Gewuerztraminer and Mueller-Thurgau grape pomace for the 3-mercaptohexan-1-ol precursors and 4-S-cysteinyl-4-methylpentan-2-one. The grape cultivar is crucial, but the technological ability of enhancing the level of the volatile thiol precursors simply by treating the grape marc in different ways is a promising and powerful tool for the production of potentially flavouring tannins intended for food and beverage industry.

The recent finding that grape tannin may contain significant amount of S-glutathionylated (GSH-3MH) and S-cysteinylated (Cys-3MH) precursors of the varietal thiols 3-mercapto-1-hexanol and 3-mercaptohexyl acetate, characteristic of Sauvignon blanc wines, offers new opportunities for enhancing the tropical aroma in fermented beverages. In this study this new hypothesis was investigated: Muller Thurgau (17 samples) and Sauvignon blanc (15 samples) grapes were fermented with and without addition of a selected grape tannin. As expected, the tannin-added juices were higher in precursors, and they produced wines with increased free thiols. Preliminary informal sensory tests confirmed that in particular the Sauvignon wines produced with the tannin addition were often richer with increased “fruity/green” notes than the corresponding reference wines. This outcome confirms that grape tannin addition prior to fermentation can fortify the level of these compounds.

Volatile sulfur-containing compounds (VSCs) play an important role in wine aroma conferring at high concentrations unpleasant odors but also participating positively at low concentration. A large number of VSCs are formed at different stages of winemaking and storage. To monitor this phenomenon, a HS-SPME-GC-MS/MS method has been developed. The method is proposed in order to quantify 27 different sulfur-containing compounds. SPME extraction was performed using a carboxen-polydimethylsiloxane (CAR-PDMS) fiber, which resulted the most effective fiber coating. Time and temperature extraction conditions were optimized using response surface methodology. The selectivity and sensitivity of the method were considerably increased using triple-quadrupole in multiple reaction monitoring (MRM) mode. The number of VSCs analyzed in a single run was higher than in any other method previously reported using single-quadrupole MS or other detectors. The overall process was successfully applied to identify and quantify sulfur compounds both in white and red wines.

The present study follows arsenic (As) transfer through the chain of soil-vine-leaves-grapes-wine to assess the possible risk of arsenic intake related to consuming grapes and wines produced in 10 vineyards located in a mining area rich in this element. The results are compared with date from 18 uncontaminated areas. In the soil, the content of As extracted with acqua regia and that extracted with ammonium acetate, were analyzed. Leaves and berries were analyzed after washing with acidified aqueous solution and acid mineralization in a closed vessel, whereas wines were simply diluted before analysis. All analyses were performed using an inductively coupled plasma mass-spectrometer. The aqua regia extractable As concentration in soil ranged from 3.7 to 283 mg/kg, whereas available As varied from 18 to 639 µg/kg, and As total concentration ranged from 16.3 to 579 µg/kg dry weight in leaves and from

O aroma é um dos fatores mais importantes na determinação da qualidade e do caráter do vinho. Isso se deve à presença de compostos voláteis que estão associados às suas características organolépticas ou diferentes proporções entre estes compostos que podem ser influenciadas por fatores vitícolas (clima, solo, cultivar, manejo) e enológicos (maturação da uva, fermentação, tratamentos pósfermentativos). A região do sul de Minas Gerais vem se destacando na produção de espumantes de qualidade, e, nesse contexto, o presente trabalho teve como objetivo conhecer a influência do manejo da videira no desenvolvimento do aroma, da baga até o espumante, a fim de estabelecer associações com a qualidade do produto final. Os experimentos foram realizados com a cultivar Chardonnay em diferentes condições de manejo, em que foram avaliados clones, porta-enxertos, sistemas de condução e densidades de plantio. Foram analisados os compostos voláteis livres por HS-SPME/GC-MS das bagas, mostos, vinhos base e espumantes nas safras 2016, 2017 e 2018. O trabalho foi dividido em quatro partes para a apresentação dos resultados. A primeira consistiu em verificar a influência do material genético na composição volátil da cv. Chardonnay com os experimentos de clones e portaenxertos; a segunda parte avaliou a composição volátil do clone 809 até o espumante; a terceira, em analisar as vinificações dos diferentes sistemas de condução; e a quarta, em avaliar a evolução dos compostos voláteis da baga ao espumante e analisar os aromas que as densidades de plantio podem conferir ao espumante. As principais classes de compostos aromáticos identificados nas matrizes foram: C6-C9 aldeídos, álcoois superiores, aldeídos ramificados, benzenoides, monoterpenoides, norisoprenoides, sesquiterpenoides, cetonas e ácidos graxos. Os resultados mostraram que os clones e os porta-enxertos apresentaram perfis voláteis diferentes, indicando que a variabilidade entre os clones e que a enxertia têm influência no metabolismo da baga; o clone 809 apresenta maior abundância de compostos monoterpenoides, confirmando o seu caráter moscato, das uvas aos espumantes; os diferentes sistemas de condução e densidades de plantio alteram o metabolismo da14 baga, refletindo no perfil volátil dos espumantes nas safras estudadas. Dessa forma, os dados indicam que a composição volátil sofre influência do manejo da videira ao espumante. Aroma is one of the most important factors in determining the quality and character of wine. This is due to the presence of volatile compounds that are associated with their organoleptic characteristics or different proportions among these compounds that can be influenced by viticultural (climate, soil, cultivar, management) and oenological factors (grape maturation, fermentation, post fermentation treatments). The southern region of Minas Gerais has been standing out in the production of quality sparkling wines, and in this context, the purpose of the present work was to learn about the influence of grapevine management on the development of aroma, from berry to sparkling wine, in order to establish associations with the quality of the final product. The experiments were carried out with the Chardonnay cultivar under different management conditions, in which clones, rootstocks, trellising systems and planting densities were evaluated. The free volatile compounds by HS-SPME/GC-MS of the berries, musts, base and sparkling wines in the 2016, 2017 and 2018 harvests were analyzed. The work was divided into four parts in order to present the results. The first part consisted of verifying the influence of genetic material on the volatile composition of the cv. Chardonnay with the experiments on clones and rootstocks; the second part evaluated the volatile composition of clone 809 up to the sparkling wine; the third one part analyzed the vinification of the different trainig systems; and the fourth part evaluated the evolution of the volatile compounds from the berry to the sparkling wine and analyzed the aromas that the planting densities can confer to the sparkling wine. The main classes of aromatic compounds identified in the matrices were: C6-C9 aldehydes, higher alcohols, branched aldehydes, benzenoids, monoterpenoids, norisoprenoids, sesquiterpenoids, ketones and fatty acids. The results showed that the clones and the rootstocks have different volatile profiles, indicating that variability among clones and that grafting have great relevance to the berry secondary metabolism; the 809 clone presents a greater abundance of monoterpenoid compounds, confirming its muscat character, from grapes to sparkling wines; the different training systems and planting densities alter the berry´s metabolism, reflecting16 in the volatile profile of sparkling wines in the studied harvests. The data indicate that the volatile composition is influenced by the management of the berry to the sparkling wine.