Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. / Made available in DSpace on 2012-10-18T22:27:13Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-09T04:16:00Z : No. of bitstreams: 1 151973.pdf: 10782459 bytes, checksum: f403101da283921cf7a942cb5ba38b0d (MD5) / A síntese de acetoína por Hanseniaspora guilliermondii a partir de glicose como fonte de carbono sob condições aeróbias é estudada. Um planejamento experimental e análise de superfície de resposta são desenvolvidos para avaliar a influência da concentração inicial de glicose, temperatura e pH na produção de acetoína. Os ensaios foram desenvolvidos em frascos agitados contendo meio YM à temperatura controlada. Um monitoramento do consumo de glicose, produção de biomassa e metabólitos (acetoína, acetato de etila e etanol) foi realizado. Os efeitos da concentração inicial de glicose e da temperatura apresentaram-se significativos para a resposta concentração máxima em acetoína. Já para a resposta produtividade, a concentração inicial de glicose e a interação entre temperatura e pH foram os efeitos que apresentaram significância estatística. Modelos empíricos para a produtividade e concentração máxima de acetoína foram determinados, os quais demonstraram-se não só significativos, como também preditivos. A otimização do processo foi realizada determinando-se os pontos de máximo nas equações representativas dos modelos acima citados. As condições ótimas encontradas são concentração inicial de glicose de 63 g/l e temperatura de 28 oC para a obtenção de uma concentração máxima em acetoína, sendo esta em torno de 365 mg/l. O ponto máximo considerando a produtividade e a concentração de acetoína é encontrado nas condições de concentração inicial de glicose igual a 64 g/l, temperatura de 30 oC e pH de 4,5.

Orientador : Orlando Bravo / Dissertação (mestrado) - Universidade Estadual de Campinas. Faculdade de Tecnologia de Alimentos / Made available in DSpace on 2018-07-14T06:13:56Z (GMT). No. of bitstreams: 1 Brealey_Orlando_M.pdf: 1314331 bytes, checksum: 34df48fc47c3aa926bf65e8ba48b6327 (MD5) Previous issue date: 1972 / Resumo: Por ser extremamente difícil evitar a perda do aroma nos alimentos, quando estes são processados, é que a ciência tem se dedicado, nas últimas décadas, à tarefa de isolar e identificar os componentes voláteis responsáveis por essa propriedade sensorial. O advento da cromatografia de gás e da espectrometria de massas, assim como o melhoramento das técnicas analíticas de extração, tem permitido grandes progressos neste campo, durante os últimos anos. Nesta investigação bibliográfica discutir-se-ão os caminhos seguidos pelos pesquisadores, com o objetivo de determinar e identificar os componentes voláteis da laranja e sua correlação com o aroma. / Abstract: Due to the fact that is extremely difficult to avoid a loss of aroma in foods during processing, intensive studies have been carried out in the last few decades on the isolation and identification of the volatile compounds responsible for food aromas. The advent of gas-chromatography and mass spectrometry, as well as the improvement of analytical techniques, during the last few years , has made possible a considerable progress in this field. In this bibliographic survey will be discussed the methods employed by the researchers to determine and identify the volatile compounds of the orange and their correlation with the aroma. / Mestrado / Mestre em Tecnologia de Alimentos

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Für die Authentizitätsbewertung achiraler Aromastoffe ist die gaschromatographische Isotopenverhältnismessung mittels massenspektrometrischer Analyse ein etabliertes Verfahren. Diese Technik ermöglicht es, über geeignete Datenbanken authentischer Referenzproben gesicherte Aussagen hinsichtlich deren Herkunft aus natürlicher oder synthetischer Quelle zu treffen. Zunehmend ins Interesse rückt allerdings auch die Frage, ob es mittels Techniken der Stabilisotopenanalytik ebenso möglich ist, das breite Feld der legislativ als „natürlich“ deklarierten Aromastoffe analytisch weiter in deren Herkunft aus biotechnologischer oder natürlicher („ex plant“) Quelle aufzutrennen. Zwar kann dieser Fragestellung prinzipiell über die Erweiterung bestehender Stabilisotopen-Datenbanken mit authentischen Proben nachgegangen werden, sie scheitert jedoch häufig an der limitierten Verfügbarkeit authentischer biotechnologischer Referenzen oder der eingeschränkten Kenntnis über die der Produktion „natürlicher“ Aromastoffe zugrundeliegenden Verfahrenstechniken. Eine mögliche Vorgehensweise zur Umgehung dieses Sachverhalts stellt daher die in Anlehnung an beschriebene biotechnologische Verfahren im Labormaßstab durchgeführte Produktion ausgewählter und somit auch authentischer Referenz-Aromastoffe dar. Diese Methode hat zudem den Vorteil, dass gegebenenfalls zusätzliche Informationen über mögliche Isotopenfraktionierungen in solchen Systemen ermittelt werden können, welche sich nicht nur zur Authentizitätsprüfung als nützlich erweisen können, sondern auch zur stetig wachsenden Grunderkenntnis über Isotopenfraktionierungen in biologischen Systemen beitragen. Ziel der vorliegenden Arbeit war es daher, der geschilderten Fragestellung bezüglich ausgewählter Aromastoffe aus den Gruppen der C6-Aldehyde und -Alkohole („Grünnoten“) sowie der Gärungsalkohole nachzugehen. Zu diesem Zweck erfolgten zum einen im Labormaßstab die biogenetische Bildung von C6-Aldehyden und -Alkoholen ausgehend von den ungesättigten Fettsäuren Linol- und Linolensäure, ferner wurden parallel Edukte, Intermediate und Produkte isoliert und hinsichtlich ihrer Stabilisotopengehalte durch Bestimmung der Delta-2H(V-SMOW)- und Delta-13C(V-PDB)-Werte untersucht. Zum anderen sind auf fermentativem Wege ausgehend von unterschiedlichen Kohlenhydratquellen die Gärungsalkohole 2-Phenylethanol und 2-Methyl-1-propanol dargestellt worden. Des weiteren galt es, die bei den Gärungsalkoholen resultierende Datenlage dahingehend zu prüfen, ob sich diese über eine Korrelation der Delta-2H(V-SMOW)- und Delta-13C(V-PDB)-Werte dazu eignet, eine Authentizitätsbewertung dieser Aromastoffe hinsichtlich natürlicher oder synthetischer Herkunft zu ermöglichen. / For the authenticity assessment of achiral flavor substances gas chromatography-isotope ratio mass spectrometry (HRGC-IRMS) is an established method. Using authentic reference data, this technique allows the differentiation between a “natural” or synthetic origin. The problem, however, to distinguish biotechnologically produced “natural” flavors from other “natural” ones, e.g. “ex plant” origin, is still unsolved. A suitable approach would be to expand the already existing stable isotope databases using authentic samples. However, this often fails due to the limited availability of authentic biotechnological references or restricted knowledge about the production processes for “natural” flavors. An appropriate alternative is the controlled production of authentic reference flavors according to published biotechnological processes on a laboratory scale. With this strategy additional information about eventual isotopic fractionations can be obtained, which is not only useful for authenticity assessment, but also to extend our basic knowledge about isotopic discriminations in biological systems. The aim of the present study was therefore to elucidate this question regarding selected flavor substances from the groups of the C6-aldehydes and -alcohols (“green notes”), as well as some fermentation alcohols. For this purpose, the biogenetic production of C6-aldehydes and -alcohols from the unsaturated fatty acids linoleic and linolenic acid was realized, and, in parallel, educts, intermediates and products were isolated and analysed as to their delta-2H(V-SMOW)- and delta-13C(V-PDB)-values. In addition, the fermentative production of 2-phenylethanol and 2-methyl-1-propanol was performed by using different sources of carbohydrates. Regarding these fermentation alcohols, the resulting data should also be tested, whether the correlation of the delta-2H(V-SMOW)- and delta-13C(V-PDB)-values enables the authenticity assessment of the flavor substances towards their synthetic or “natural” origin.

Processing techniques for red wines and their potential health benefits have intensively been investigated, however, information relevant to the grape and wine industry in Texas is less frequently available. The overall objective of this work was to investigate the reduction of 3-alkyl-2-methoxypyrazines that can affect the quality of Texas wines and to study the health benefits of Texas wines. The methods used include SPME-GC-MS and molecular bioassays. The first objective was to demonstrate the anti-inflammatory potential effect of red wine polyphenols from Black Spanish wine (Vitis aestivalis hybrid) in colonic human fibroblast cells. Results show that an extract prepared from Black Spanish wine decreased gene expression and activation of NF-kB transcription factor and target proinflammatory cytokines and cell adhesion molecules. Induction of microRNA-126 (miR- 126) by wine extract was found to be one of the underlying molecular mechanism by which wine extract decreased vascular cell adhesion molecule (VCAM-1) and inflammation in colon cells. These mechanisms may be relevant to the prevention of iv inflammatory bowel disease (IBD) that may increase the risk for colon cancer. The second objective was to investigate the role of the green june beetle (GJB ) as exogenous source of MPs other than the multicolored Asian Lady beetle (Harmonia axyridis). Over the last decade, the green june beetle has been suspected to be a source of MPs based on intermittent reports from Texas growers of an atypical aroma and flavor reminiscent of crushed green June beetles (GJB). Specifically the North region of Texas seems affected. Results demonstrated GJB as source of 3-isopropyl-2- methoxypyrazine, where one GJB could elevate MPs above sensory perceptible levels in 4.3 gallons of wine. The incorporation of GJB to the winemaking process may contribute negatively to the sensory properties of Texas wines and therefore should be strictly controlled. The third objective was to explore the potential effect of micro-oxygenation treatment and accelerated aging techniques relevant for the state of Texas in the reduction of 3-Isobutyl-2-methoxypyrazine (IBMP), and 3-isopropyl-2-methoxypyrazine (IPMP) levels as determined by SPME-GC-MS. Results show that MPs were not affected by MOX or oak interaction. Although the data suggest that MOX and oak exposure do not directly affect MPs concentration. The fourth research objective was to explore the potential effect of three commercial available yeast strains, BM45, K1, and D80, on MPs levels in Black Spanish wines. Black Spanish wines were fermented with MB45 strain resulted in the highest amount of MPs. Conversely K1 and D80 yeast strains reduced IBMP levels in comparison with the control. An increase in IBMP was not expected. However it has been demonstrated that amino acids valine and leucine are MPs precursors. If Vitis v aestivalis hybrid grapes contained a similar methyltransferase enzyme found in Vitis vinifera grapes and S. cerevisiae contained similar IPMP biosynthesis pathway found in Pseudomonas perolens BM45 may have led to the increased IBMP observed in the fermentation. In addition we evaluated MPs levels of wines fermented over 20 days with a chemical defined grape juice medium containing a concentration of yeast available nitrogen of 200 mg N/L. Data suggest that wines fermented with BM45 and D80 yeast strains reduced IBMP but K1 yeast did not show any effect in comparison with the control. In addition MPs were evaluated in the yeast mannoproteins fraction. Results show the presence of IBMP in low concentration below the method detection limit. This data demonstrate for the first time that yeast mannoproteins binds IBMP. to evidence for interactions between mannoproteins secreted by the D80 yeast strain and IBMP. This work will provide valuable information regarding the potential health benefits of Vitis aestivalis hybrid grapes and reduction of MPs and thus improving the quality of Texas wines

The aim of this diploma thesis was to study the literature related to terpene compounds in aromatic varieties of wine and to describe muscat and tramin variety. The study used varieties 'Irsai Oliver', 'Moravian Muscat' and 'Red traminer'. For these varieties in a given year, was determined content of free and bound terpene compounds in berries and wine. There was different time of must maceration for given varieties, namely 5, 12, 24 hours and control without maceration of pomace. The experimental part of the thesis dealt with assessment of the terpene compounds and sensory evaluation. The aim was to find out which terpene compounds are characteristic for different wine varieties and what is the most suitable length of maceration for the particular wine variety.

Orientador: Natália Soares Janzantti / Banca: Maria Regina Bueno Franco / Banca: Magali C. Monteiro da Silva / Resumo: A uvaia (Eugenia pyriformis cambess) é uma fruta exótica que apresenta sabor adocicado e ácido, típica da Mata Atlântica. A revisão da literatura mostrou que, até o presente momento, não existe estudo sobre a composição de voláteis de uvaia, assim como não se conhece os compostos voláteis odoríferos importantes para a sua qualidade sensorial. Os parâmetros físico-quimicos da polpa da uvaia foram avaliados. A polpa de uvaia apresentou teor de sólidos solúveis de 5,0 ºBrix, pH 3,80, ratio de 4,65, teor de ácido ascórbico 54,06 mg/100 mL de polpa, teor de compostos fenólicos totais de 79,94 mg de ácido gálico/100 mL e foi caracterizada como uma fruta de baixa acidez (1,08 g de ácido cítrico/100 mL), conteúdo de açúcares predominantemente de açúcares redutores (açúcares redutores 2,81 g de glicose/100 mL, açúcares totais 2,81 g de glicose/100 mL) e elevada atividade antioxidante total (656,29 μmol de Trolox/100 mL de polpa). Os compostos voláteis da uvaia foram isolados usando a técnica de headspace dinâmico. As condições para o isolamento dos compostos voláteis de uvaia foram a captura por 3 horas e eluição com hexano. O isolado obtido foi representativo da amostra original de uvaia. Os compostos voláteis foram separados por cromatografia gasosa de alta resolução e identificados por cromatografia gasosa-espectrometria de massas, índices de retenção e uso de padrões puros. Foram detectados 55 compostos voláteis, dos quais 43 foram identificados, compreendendo 19 terpenos, 16 ésteres, 3 álcoois, 1 cetona e 4 compostos pertencentes a outras classes químicas. Os compostos majoritários na uvaia foram butanoato de etila com 27,82% da área relativa total do cromatograma, hexanoato de etila com 20,04%, octanol com 8,56%, D-limoneno com 7,16% e vinilbenzeno com 6,57%. Os compostos voláteis do headspace da uvaia foram avaliados por análise... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The uvaia (Eugenia pyriformis cambess) is a Brazilian exotic fruit that presents a sweet and sour flavor, native to the Mata Atlântica. A review of the literature shows that no research has been conducted on the volatile composition of uvaia, as well as on its sensory quality. The physicochemical parameters were analyzed in the uvaia pulp. The uvaia pulp showed 5,0 ºBrix for soluble solids, pH 3,80, ratio 4,65, 54,06 mg ascorbic acid/100 mL pulp, 79,94 mg acid galic/100 mL pulp for phenolic compounds, and was characterized as a low acidic fruit (1,08 g citric acid/100 mL), sugar content predominantly of reducing sugars (2,81 g glucose/100 mL for reducing sugars, 2,81 g glucose/100 mL for total sugars), high antioxidant activity (656,29 μmol Trolox/100 mL pulp). The volatile compounds from the headspace of the uvaia were isolated using the dynamic headspace technique. The conditions fixed for the isolation were three hours of trapping and elution with hexane. The isolate obtained was representative of the original uvaia sample. The volatile compounds were separated by high resolution gas chromatography and identified by gas chromatography/mass spectrometry, retention indices and pure reference compounds. Fifty-five compounds were detected, from which forty-three were identified, comprising 19 terpenes, 16 esters, 3 alcohols, 1 ketone and 4 miscellaneous. Major compounds were ethyl butanoate (27,82% of the chromatogram's total area), ethyl hexanoate (20,04%), octanol (8,56%), D-limonene (7,16%) and vinylbenzene (6,57%). The volatile compounds from the headspace of the uvaia pulp were evaluated by five trained judges using the OSME olfactometry technique. Forty-nine odorants were found in the sample, twenty-eight of which were identified. The most important odorant were ethyl hexanoate, ethyl butanoate, methyl butanoate, ethyl 2-butenoate and hexyl hexanoate... (Complete abstract click electronic access below) / Mestre

Orientador: Glaucia Maria Pastore / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-23T02:49:12Z (GMT). No. of bitstreams: 1 Macedo_GabrielaAlves_D.pdf: 9030250 bytes, checksum: 47a229aeca60ac9fd2f042205a387ab7 (MD5) Previous issue date: 1997 / Resumo: A síntese por esterificação direta de 54 ésteres de cadeia curta, componentes de aroma, foi testada utilizando lípases microbianas não comerciais de Geotrichum sp, Alcaligenes sp, Aspergillus linhagem 1068 e 1099 sp, Rhizopus sp e a lipase comerciai de Candida rugosa. Os ésteres testados foram os derivados dos ácidos acético, butírico, propiônico e láurico com os álcoois metanol, etanol, propanol, isopropanol, butano!, isobiitanol, isopentanol, citronelol e óleo fúsel, constituído por uma mistura de álcoois onde predomina o álcool isoamilico. As lipases não comerciais foram produzidas no Laboratório de Bioquímica de Alimentos da UNICAMP. A síntese foi realizada em meio livre de solvente orgânico e adição de água. Muitos ésteres foram sintetizados com boas taxas de conversão, as quais dependeram do tipo de substrato e da especificidade da lípase empregada. Foram selecionadas as lípases de Geotrichum sp e Rhizopus sp bem como os ésteres acetato, propionato e butirato de isoamila, para o estudo e otimização das condições de síntese. Foi realizado um delineamento experimental inicial do tipo íátorial completo com pontos centrais a fim de se avaliar o efeito das variáveis: temperatura, relação molar entre substratos, quantidade de lípase e tipo de lípase no processo. Como resultado deste delineamento experimental inicial foi selecionada a lípase de Rhizopus sp dentre as duas lípases testadas por ter apresentado melhor rendimento e produtividade na síntese dos três ésteres. A concentração enzimática e relação molar entre os substratos foram, as variáveis mais importantes na síntese dos ésteres acetato e butirato de isoamila. Para a síntese do propionato, a temperatura também foi importante no processo. Em seguida foi realizado um segundo delineamento experimental fatorial completo com dois níveis mais os pontos central e axiais, totalizando 5 condições para cada variável estudada na síntese de cada éster a fim de se otimizar as condições do processo proposto para a síntese dos ésteres acetato, propionato e butirato de isoamila. Baseado nos resultados obtidos, foi passível estabelecer as condições ótimas para a síntese de acetato e butirato de isoamila; relação molar entre ácido e álcool de (1,5:l),concentração enzimática em massa dos reagentes de 5,5 %,temperatura de 40 °C, após 48 horas de reação. Foi também possível estabelecer as condições ótimas para a síntese de propionato de isoamila: relação molar entre ácido e álcool de (3:1), concentração enzimática ein massa dos reagentes de 5,5 %, temperatura de 50 °C, após 48 horas de reação. / Abstract: The preparative synthesis of 54 short chain flavour esters by non commercial lipases from Geotrichum sp, Rhizopus sp, Aspergillus sp, Alcaligenes sp and commercial Candida rugosa, was investigated in organic solvent free medium. Acetic, propionic, butyric and lauric acids as well as methanol, ethanol, butanol, i-butanol, propanol, i-propanol, i-pentanol, citronellol and fusel oil, were used as substrates. The non commercial lipases were isolated and produced in the Laboratório de Bioquímica de Alimentos of UNICAMP. Most of the esters were synthesized in good yield by at least one of the lipase specificity toward the acid or alcohol moiety of the ester. It was selected the lipases from Geotrichum sp and Rhizopus sp to continue the study and optimize the sinthesys of isoamyl acetate, butyrate and propionate esters. A two level Fatorial Design (with central point) was used to evaluate the effects of synthetic variables, such as temperature, molar ratio of isoamyl to acid, enzyme amount and type of lipase used. Rhizopus sp lipase was the most effective in the synthesis. Molar ratio and amount of lipase were the most important variables for the isoamyl acetate and butyrate synthesis. Temperature was important to propionate synthesis. Another five level central composite design were used to optimize the synthesis of these three esters. Based on surface plots, optimum conditions to the isoamyl acetate and butyrate synthesis were; time reaction 48 hours, temperature 40°C, enzyme amount 5,5 % and molar ratio (alcohol: acid) ( 1,5:1). Based on surface plots, optimum conditions to the isoamyl propionate synthesis were: time reaction 48 hours, temperature 50°C, enzyme amount 5,5 % and molar ratio (alcohol: acid) (3:1) / Doutorado / Doutor em Ciência de Alimentos