A carne de frango apresenta vários problemas no processamento e conservação, sendo a oxidação lipídica um dos principais fatores limitantes da qualidade e aceitabilidade comercial deste produto. A indústria de alimentos busca desenvolver novas formulações que visem melhorar a qualidade e, principalmente, a segurança dos produtos alimentícios. Neste sentido, o uso de antioxidantes de fontes naturais, como os extratos de semente e casca de uva, mostra-se como uma alternativa segura e saudável para o processamento de carne de frango. O objetivo desse estudo foi caracterizar quimicamente extratos de semente e casca de uva das variedades Isabel e Niágara (Vitis labrusca) e determinar a atividade antioxidante e o efeito destes extratos sobre a estabilidade oxidativa e a qualidade da carne de frango processada e armazenada sob refrigeração (4±1ºC), em dois tipos de embalagem (aeróbica e a vácuo). Os compostos fenólicos dos extratos foram quantificados e a identificação feita pelo método da cromatografia líquida de alta eficiência (CLAE). A atividade antioxidante foi determinada pelo método do seqüestro do radical DPPH e pelo método da inibição da peroxidação lipídica. Primeiramente, carnes de frango processadas, contendo diferentes concentrações dos extratos (10, 20, 40 e 60 mg compostos fenólicos totais (CFT)) foram avaliadas em relação à estabilidade oxidativa. Posteriormente, as concentrações 40 e 60 mg CFT foram testadas, em embalagem aeróbica e a vácuo, sob refrigeração, por um período de 14 dias, sendo avaliadas a estabilidade oxidativa e a qualidade da carne. Os extratos de semente e casa de uva da variedade Niágara apresentaram os maiores teores de compostos fenólicos em relação os da variedade Isabel, sendo que pela técnica de CLAE foi possível identificar e quantificar os flavonóides catequina e epicatequina. Esses extratos apresentaram alta atividade antioxidante in vitro, sendo esta atividade atribuída à presença de compostos fenólicos. Os extratos de semente e casca de uva das variedades Isabel e Niágara (Vitis labrusca) demonstraram resultados satisfatórios quanto à estabilidade oxidativa, e quando aplicados nas concentrações de 40 a 60 mg CFT apresentaram resultados semelhantes ao antioxidante sintético BHT. A eficiência dos extratos de semente e casca de uva foi altamente dependente da concentração utilizada. A adição dos extratos de uva combinado com a embalagem a vácuo demonstrou ser uma boa técnica para aumentar a estabilidade lipídica na carne de frango cozida sob refrigeração, a 4±1ºC, num prazo de armazenamento de 14 dias. / Poultry meat has serious problems regarding processing and conservation. The lipid oxidation is one of the main factors limiting the quality and commercial acceptance of meat. The food industry has been trying to develop new formulations in order to improve the quality, and mainly, the safety of food products. Therefore, the use of natural antioxidants, such as grape seed and peel extracts, can be a safe and healthy alternative to poultry meat processing. The aim of this study was to chemically characterize grape seed and peel extracts from Isabel and Niagara varieties (Vitis labrusca) and to assess antioxidant activity and effect of these extracts on the quality and oxidative stability of processed and cold stored (4±1ºC) poultry meat, into two package types (aerobic and vacuum packaging). After quantified, the phenolic compounds found in the extracts were identified by the high-performance liquid chromatography (HPLC) method. The antioxidant activity was determined by the free radical scavenging activity on the DPPH method and by the linoleic acid peroxidation method. In a first essay, processed poultry meat, treated with different extracts concentrations (10, 20, 40 and 60 mg of total phenolic compounds (CFT)) were evaluated in relation to the oxidative stability. In sequence, the 40 and 60 mg CFT concentration extracts were tested over processed and cold stored poultry meat, packaged under aerobic and vacuum conditions, during 14 days; the poultry meat was then evaluated with regard to quality and oxidative stability. Due to the presence of catechins and epicatechin flavonoids, extracts from both grape varieties exhibited high in vitro activity. However, Niagara variety extract showed higher values of CFT when compared to Isabel variety. When applied to poultry meat, the grape seed and peel extracts from both varieties exhibited satisfactory results in relation to oxidative stability. Moreover, when applied with concentrations of 40 and 60 mg CFT, these extracts showed results similar to the ones found with BHT synthetic antioxidant. The grape extract efficiency showed high dependence of extract concentration. The addition of grape extracts combined with a vacuum package can be considered a good technique to raise lipid stability in cooked and cold stored (4±1ºC) poultry meat, until 14 days of storage.

A indústria alimentícia tem oferecido ao consumidor muitas opções para aquisição de pães, dentre essas estão os pães enriquecidos e os integrais. A linhaça é um alimento com alegação funcional que vem se destacando pela presença do Omega-3, fibra solúvel e proteína, porém seu consumo é baixo devido à falta de hábito e também por escassez de informação dos consumidores. O objetivo do estudo foi formular pães com adição de grãos de linhaça nas concentrações de 3%, 6% e 9% e compará-los ao controle, sem adição de linhaça. Foram realizadas análises de determinação do perfil de ácidos graxos, composição centesimal, quantificação do teor de minerais, determinação de antinutricionais (ácido fítico, taninos, compostos fenólicos totais), digestibilidade de proteína in vitro, análise da qualidade dos pães através do peso da massa crua, peso da massa assada, perdas durante a cocção e índice de conversão. As propriedades físicas dos pães também foram avaliadas através da textura, volume e cor. As características sensoriais foram analisadas através de teste de aceitabilidade realizado em padaria com 116 provadores e também pela Análise Descritiva Quantitativa (ADQ) com 13 provadores treinados. Com os dados obtidos das análises químicas, elaborou-se um rótulo nutricional para cada formulação. Dentre os ácidos graxos quantificados, o palmítico, o oléico e o linoléico foram os maiores representantes nas 4 amostras de pães o que contribuiu para a frágil estabilidade dos produtos e para a formação de compostos indesejáveis, porém a presença de antioxidantes naturais nas sementes de linhaça controlou a oxidação lípidica. Nenhuma das amostras pode ser considerada fonte de fibra alimentar pelo fato de não conter 3g/100g de alimento pronto para consumo. O teor de fitatos presente nas amostras aumentou de acordo com a adição de sementes de linhaça. Nas 4 formulações de pães o teor de fitato diminuiu significativamente quando comparado ao da semente de linhaça. As amostras controle e com 6% de linhaça foram classificadas como volume específico Muito bom e as amostras com 3% e 9% de linhaça foram classificadas como volume específico Bom. Entre as amostras que receberam adição de linhaça, a amostra com 9% foi a melhor aceita pelos provadores e na ADQ, essa amostra apresentou médias superiores às demais em relação a maioria dos atributos levantados pelo provadores. Não foram identificados atributos indesejáveis para nenhuma das amostras através da ADQ. / Food industries offer to consumer several types of breads options which vary from whole wheat to enrich with multigrain such with flax seed. Flax seed is considered a functional food that has important content of omega 3 fat acids, soluble fiber and protein, however it intakes is very low in our diet. The aim of the research was to prepare a wheat bread enrich with flax seed at 3% or 6% or 9% concentration and to compare with a wheat bread control with no flax seed added. Analysis of fat acids composition, mineral composition, antinutritionals content (phytic acid, tannin, total phenolic compounds) and in vitro protein digestibility were carried out in the bread samples. Bread quality was evaluated analyzing the weight of the raw dough, the baked bread, and the lost during baking process and its conversion index. Physical properties of breads were evaluated for texture, volume and color. The sensory characteristics were evaluated using acceptability test with 116 panelists and by quantitative descriptive analysis (QDA) with 13 trained panelists. A nutritional label was formulated to each one of the bread preparations. The quantified fat acids profile showed that palmitic, oleic and linolenic acids were the most representative fat acids in the 4 bread sample analyzed. The presence of those fat acids possibly contributes to poor stability of product and for the development of undesirable compound. However, the presence of natural antioxidants in flax seed may help to control fat acid oxidation. None of the samples were considered source of dietary fiber because they have less then 3g/100 g of bread. The phytate content present in the samples increased according to the increase of flax seed concentration in the bread. Compared to raw flax seed, the phytate content in the bread samples were lower. The control and the sample with 6% of flax seed had the ranking for specific volume described as Very good and the samples with 3% and 9% of flax seed as Good. Between the bread samples, the best score in the acceptability test was obtained in the sample with 9% of flax seed. The same was observed for QDA which showed that the panel had high attributes for this sample compared to other ones. No undesirable attributes were identified in any other sample analyzed in QDA.

O setor agroindustrial tem se expandido muito nos últimos anos, levando o país a um aumento na geração de resíduos agroindustriais, sendo que a maior parte deles ainda é descartada no meio ambiente, sem tratamento adequado, ou utilizada na alimentação animal, destinos que a priori, não geram ganhos econômicos para a agroindústria além de representarem gargalos logísticos e ambientais na sua disposição. Nesse sentido, o presente trabalho teve como objetivos otimizar o processo de extração de compostos bioativos, avaliar in vitro as atividades antioxidante, por meio da desativação de espécies reativas de oxigênio, e anti-inflamatória, bem como determinar a composição fenólica dos resíduos agroindustriais a saber: película de amendoim (Arachis hypogaea) (cultivares IAC886 e IAC505), pimenta-rosa (Schinus terebinthifolius Raddi) e pimenta-do-reino (Piper Nigrum L). O processo de otimização da extração de compostos antioxidantes foi realizado utilizando dois processos de extração, extração convencional e subcrítica, em delineamento composto central rotacional, utilizando como variáveis a temperatura e tempo e a pressão e temperatura, respectivamente, com os solventes etanol 80%, água e propilenoglicol 80%. Durante o processo de otimização a atividade antioxidante foi avaliada pelo método de sequestro do radical ABTS. Os melhores resultados foram obtidos para a extração convencional com os solventes etanol 80%, água e propilenoglicol 80%. A película de amendoim (IAC505) apresentou as maiores atividades antioxidantes (1.396,67, 580,44 e 859,89 μmol.g-1 em equivalentes de trolox, para os solventes etanol 80%, água e propilenoglicol 80%, respectivamente). A partir dos resultados obtidos para os solventes testados, utilizando a extração convencional, foram feitas outras análises de atividade antioxidante considerando o tempo e temperatura ideal de extração. Foram realizadas análises de avaliação da capacidade de redução de Folin-Ciocalteau e potencial de desativação dos radicais livres sintéticos (DPPH e ABTS) e espécies reativas de oxigênio (radicais peroxila, superóxido e ácido hipocloroso). O solvente de extração que apresentou melhores resultados em todos os ensaios foi o etanol 80%, sendo, portanto o solvente utilizado nas análises subsequentes. A partir da definição do melhor sistema extrator foram realizadas análises da composição fenólica, por meio das técnicas de cromatografia líquida de alta eficiência em modo analítico (HPLC-RP), cromatografia gasosa acoplada com espectrometria de massas (GC-MS), e avaliação in vitro da atividade anti-inflamatória. Foram identificados nos resíduos estudados procianidinas B1 e B2, ácido p-cumárico, miricetina, ácido ferúlico, ácido siríngico, ácido sinápico, epicatequina e catequina. A pimenta-do-reino diminui significativamente os níveis de TNF-α e nitritos, reduzindo assim o processo inflamatório gerado. Os resultados obtidos neste trabalho demonstram que estes resíduos agroindústrias possuem grande potencial biológico, podendo assim ser melhores aproveitados tanto pela indústria de alimentos quanto pela indústria farmacêutica. / The agribusiness sector has expanded greatly in recent years, leading the country to an increase in the generation of agro-industrial residues, even though most of them are still discarded in the environment without proper treatment, or used in animal feed, destinations that a priori do not generate economic gains for agribusiness besides representing logistical and environmental bottlenecks at your disposal. In this sense, the present study aimed to optimize the bioactive compounds extraction process, to evaluate in vitro the antioxidant activities, through the deactivation of reactive oxygen species, and anti-inflammatory as well as determine the phenolic composition of agro-industrial residues namely peanut skin (Arachis hypogaea) (IAC886 and IAC505 cultivars), pink pepper (Schinus terebinthifolius Raddi) and black pepper (Piper nigrum L). The optimization process of extraction of antioxidants was performed using two extraction processes, conventional extraction and subcritical on central composite design, using as variable temperature and time and the pressure and temperature, respectively, with solvents ethanol 80%, water and propyleneglycol 80%. During the optimization process the antioxidant activity was evaluated for the kidnapping method of ABTS radical. The best results were obtained for the conventional extraction with solvents ethanol 80%, water and propyleneglycol 80%. Peanut skin (IAC505) showed the highest antioxidant activity (1,396.67, 580.44 and 859.89 μmol.g-1 in Trolox equivalents, for solvents ethanol 80%, water and propyleneglycol 80%, respectively). From the results obtained for the solvents tested, using conventional extraction, other analyzes were done considering the antioxidant activity optimum time and temperature of extraction. Valuation analyzes were carried out of the Folin-Ciocalteau reduction capability and potential disabling of synthetic free radical (DPPH and ABTS) and reactive oxygen species (peroxyl radicals, superoxide and hypochlorous acid). The extraction solvent that showed better results in all tests was ethanol 80%, and therefore the solvent used in subsequent analyzes. From the definition of the best extraction system analyzes were made of phenolic composition by means of liquid chromatography techniques of high efficiency in analytic way (HPLC-RP), gas chromatography coupled with mass spectrometry (GC-MS), and reviewed in vitro anti-inflammatory activity. They were identified at residues studied procyanidins B1 and B2, p-coumaric acid, myricetin, ferulic acid, syringic acid, sinapic acid, epicatechin, and catechin. The black pepper significantly reduces TNF-α and nitrite levels, thereby reducing the inflammatory process generated. The results of this study demonstrate that these agribusinesses waste have great biological potential, and thus can be best availed by both the food industry and the pharmaceutical industry.

Os compostos fenólicos e os glucosinolatos vêm sendo pesquisados quanto à atividade antimicrobiana contra diversos microrganismos patogênicos, dentre eles a Listeria monocytogenes, um perigoso contaminante de alimentos. Este trabalho teve como objetivo principal avaliar resíduos agroindustriais com atividade contra Listeria monocytogenes, bem como identificar a composição química, visando a aplicação na indústria de alimentos. Neste trabalho foram analisados 23 resíduos agroindustriais. Os extratos destes resíduos foram preparados a partir de cinco solventes (hexano; clorofórmio; acetato de etila; etanol:água (80:20 v/v) e água), os quais foram utilizados na avaliação do potencial antimicrobiano contra Listeria monocytogenes por meio do teste de difusão em ágar. Os extratos que apresentaram resultado positivo foram selecionados para as análises de Concentração Inibitória Mínima (CIM), Concentração Bactericida Mínima (CBM), citometria de fluxo e composição química por CG-EM. A L. monocytogenes mostrou-se sensível apenas aos extratos aquosos de talo de brócolis e casca de abóbora moranga e extrato clorofórmico de semente de mamão apresentando valores de CIM de 102,4 mg/mL, >102,4 mg/mL e de 6,4mg/mL, respectivamente. A análise de citometria de fluxo demonstrou alterações na morfologia das células, frente aos extratos testados. A principal ação dos extratos foi em função da inibição do crescimento do microrganismo e da redução de sua população. Os extratos apresentaram uma composição química peculiar. Nos extratos de talo de brócolis e casca de abóbora foram encontrados alguns ácidos fenólicos e orgânicos, enquanto que no extrato de semente de mamão o único composto encontrado com potencial antimicrobiano foi o benzil-isotiocianato. Diante da dificuldade em evitar a contaminação de alimentos por L. monocytogenes, a utilização de compostos antimicrobianos naturais derivados de resíduos agroindustriais se mostra promissora e pode ser uma alternativa para auxiliar na segurança dos alimentos. / The phenolic compounds and glucosinolates have been investigated for their antimicrobial activity against several pathogenic microorganisms, including Listeria monocytogenes, a dangerous contaminant of food. This study has as main objective valuate agroindustrial residues with activity against Listeria monocytogenes, well as evaluate the chemical composition, aimed at their application in food industry. In this work we analyzed 23 agroindustrial residues. The extracts of these residues were prepared from five solvents (hexane, chloroform, ethyl acetate, ethanol:water (80:20 v/v) and water), which were used in evaluating the antimicrobial potential against Listeria monocytogenes by the agar diffusion test. The extracts that tested positive were selected for analysis of Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), flow cytometry and chemical composition by GC-MS. L. monocytogenes showed sensibility only to aqueous extracts of stalk of broccoli and peel pumpkin and chloroform extract of papaya seed showing MIC values of 102.4 mg / mL,> 102.4 mg / mL and 6.4 mg / mL, respectively. The flow cytometry analysis showed changes in cell morphology, front of to tested extracts. The main action of the extracts was as a function the inhibition of growth of microorganisms and reducing its population. The extracts showed a peculiar chemical composition. In extracts of broccoli stalks and peel pumpkin were found some phenolic acids and organic, while the extract in papaya seed found the single compound with antimicrobial potential was benzyl-isothiocyanate. Given the difficulties in preventing food contamination by L. monocytogenes, the use of natural antimicrobial compounds derived from agroindustrial residues shows promise and can be an alternative to aid in safety of food.

\'Piraroxa\' e \'Vanda\' são cultivares de alface cujos comportamentos pós-colheita ainda não foram caracterizados. Um dos diferenciais destas cultivares pode estar relacionado ao seu alto potencial antioxidante como resultado da ação de seus compostos fenólicos. A fim de avaliar os parâmetros pós-colheita e a viabilidade do uso destas cultivares como fontes de antioxidantes, o presente trabalho teve como objetivo investigar suas respostas fisiológicas e bioquímicas, comparando-as entre si em diferentes temperaturas de armazenamento e em épocas de colheita distintas. Tanto no verão quanto no inverno, as hortaliças foram armazenadas por 28 dias à 0ºC e 95-97%UR e por quatro dias em condição ambiente monitorada. Em todas as condições de armazenamento e períodos de colheita, não houve diferença entre as cultivares e tendências decrescentes foram observadas para a produção de etileno e as taxas respiratórias. O armazenamento refrigerado proporcionou acentuado declínio destas variáveis. Já em condição ambiente, na colheita de verão, a cv. Vanda apresentou produção superior de etileno e, na colheita de inverno, a cv. Piraroxa apresentou taxas respiratórias mais elevadas. Os parâmetros de coloração permaneceram constantes. As cultivares apresentaram tendências similares entre si, tanto para a perda de massa fresca quanto para o conteúdo de clorofila e carotenoides, e o armazenamento refrigerado e as altas umidades relativas mostraram-se eficazes para o controle da perda de massa. O conteúdo de antocianinas foi influenciado pela temperatura de armazenamento, mas não pela época de colheita, e não demonstrou estar diretamente relacionado ao potencial antioxidante da cv. Piraroxa. As características de qualidade representadas pela aparência das hortaliças foram preservadas, em armazenamento refrigerado, até o 28º dia e, em condição ambiente, até o primeiro e segundo dias. A atividade da polifenoloxidase (PPO) e o potencial antioxidante das hortaliças foram influenciados pela época de colheita, mas não pela temperatura de armazenamento. A cv. Vanda apresentou atividade da PPO superior na colheita de verão e a cv. Piraroxa apresentou potencial antioxidante superior em todas as condições de armazenamento e épocas de colheita. O teor de compostos fenólicos e a atividade sequestrante do radical livre DPPH apresentaram valores superiores na colheita de verão para ambas as cultivares, com tendências à constância de valores, enquanto o sistema-modelo ?-caroteno/ácido linoleico demonstrou tendências crescentes, com elevações significativas a partir do segundo dia de armazenamento em condição ambiente e a partir do 21º dia de armazenamento refrigerado. Os parâmetros fisiológicos analisados evidenciaram grande similaridade em relação ao comportamento pós-colheita das duas cultivares e a durabilidade e manutenção das características qualitativas das hortaliças durante o armazenamento refrigerado foi extremamente satisfatória. Em contrapartida, o armazenamento, tanto em condição ambiente monitorada quanto em refrigeração, não demonstrou constituir-se como técnica válida para a maximização do potencial antioxidante das hortaliças, embora a alface constitua fonte dietética importante de antioxidantes. / \'Piraroxa\' and \'Vanda\' are lettuce cultivars whose postharvest behavior has not yet been characterized. One of the differentials of these cultivars may be related to its high antioxidant potential as a result of its phenolic compounds action. In order to evaluate the postharvest parameters and feasibility of using these cultivars as sources of antioxidants, this study aimed to investigate their physiological and biochemical responses, comparing them to each other at different storage temperatures and at different harvest times. Vegetables were stored for 28 days at 0ºC and 95-97%RH and for four days at ambient monitored condition regardless of summer or winter seasons. In all storage conditions and harvest periods there was no difference between cultivars and decreasing trends were observed for ethylene production and respiratory rates. Cold storage provided dramatic decline of these variables. At ambient condition, however, cv. Vanda showed higher production of ethylene in the summer harvest and cv. Piraroxa had higher respiratory rates in the winter harvest. Color parameters remained constant. Cultivars showed similar trends among one another for both weight loss and the content of chlorophyll and carotenoids. Also, cold storage and high relative humidity were effective for the control of weight loss. Anthocyanins content was influenced by storage temperature, not by the harvest season, and did not show to be directly related to the antioxidant potential of cv. Piraroxa. Vegetables quality appeared to be preserved on cold storage until day 28, and at ambient condition until the first and second days. Polyphenol oxidase (PPO) activity and antioxidant potential of vegetables were influenced by harvest time, but not by the storage temperature. \'Vanda\' showed higher PPO activity in the summer harvest and \'Piraroxa\' showed higher antioxidant potential in all storage conditions and harvest times. Phenolic content and free radical scavenging activity of DPPH showed higher values in summer harvest for both cultivars, with constant value tendencies, while the model system ?-carotene/linoleic acid showed increasing trends, with significant increases in the second day of storage at ambient condition and after 21 days of refrigerated storage. The physiological parameters analyzed showed great similarity to postharvest behavior of the two cultivars, and the durability and maintenance of vegetables quality during refrigerated storage were extremely satisfactory. In contrast, both ambient and refrigerated monitored storages did not show as valid techniques for maximizing the antioxidant potential of vegetables, although lettuce constitutes an important source of dietary antioxidants.

O estudo de compostos antimicrobianos em espécies vegetais tem gerado cada vez mais interesse na indústria de alimentos, devido ao aumento da demanda por alimentos livres de conservantes sintéticos por parte dos consumidores. Espécies vegetais são ricas em compostos bioativos com reconhecidas propriedades de interesse industrial, como farmacológicas, antioxidantes e antimicrobianas. Antibacterianos naturais podem ser encontrados não só em folhas, ramos, flores, tubérculos e raízes, mas também em subprodutos gerados pelo processamento de frutas, legumes e hortaliças. O objetivo do presente estudo foi avaliar a atividade antimicrobiana de diversos resíduos agroindustriais e erva-mate para preparo de chimarrão (Ilex paraguariensis St. Hil.) sobre micro-organismos patogênicos de importância em alimentos, tais como Staphylococcus aureus, Listeria monocytogenes, Salmonella Enteritidis e Escherichia coli. Foram realizados screening da atividade antimicrobiana pela técnica da difusão em ágar, determinação das Concentrações Inibitória (CIM) e Bactericida Mínimas (CBM), análise dos efeitos dos extratos sobre o crescimento microbiano através da construção de curvas de crescimento, determinação do teor de fenólicos totais e caracterização química dos materiais de maior atividade antibacteriana. Os resultados demonstraram o potencial antimicrobiano da ervamate e de vários resíduos agroindustriais. O extrato etanólico de erva-mate mostrou ser um potente antimicrobiano natural frente às bactérias S. aureus, L. monocytogenes e S. Enteritidis. Em relação à sua composição química, foi encontrada uma grande quantidade de compostos fenólicos, porém sua atividade mostrou-se ineficiente em pH 6. Os resíduos agroindustriais de talos de beterraba, película de amendoim, bagaços de uvas Petit Verdot e Pinot Noir, sementes de uvas Petit Verdot, borra de fermentação de uvas tintas e bagaço de goiaba apresentaram atividade sobre S. aureus e L. monocytogenes. E. coli não foi inibida pelos extratos de erva-mate e por nenhum dos resíduos agroindustriais avaliados. Na composição química destes resíduos foi encontrada a presença de compostos fenólicos de reconhecida atividade antimicrobiana, demonstrando assim a importância e necessidade de pesquisas de prospecção de antimicrobianos naturais destas fontes para uso pela indústria de alimentos e bebidas. / Study of antimicrobial compounds in plant species has driven to increasing interest within the food industry due to raised demand from consumers for food free of synthetic preservatives. Vegetable species are rich of bioactive compounds with known antioxidant and antimicrobial properties worthy of industrial and pharmacological interest. Natural antimicrobials can be found not only in leaves, stems, flowers, tubers and roots, but also in by-products from processing of fruit, vegetables and greenery. This study aimed to evaluate antimicrobial activity of various agroindustrial residues and yerba mate for preparing chimarrão (Ilex paraguariensis St. Hil.) on relevant pathogenic microorganisms in foods such as Staphylococcus aureus, Listeria monocytogenes, Salmonella Enteritidis and Escherichia coli. Screening of antimicrobial activity was performed by agar diffusion technique, determination of Minimal Inhibitory Concentration and Minimum Bactericidal Concentration (MIC/MBC), analysis of extracts effects on microbial rise through elaboration of growth curves, determination of total phenolic content, and chemical characterization of the compounds with the highest antibacterial activity. Results demonstrated antimicrobial potential of yerba mate and some agroindustrial residues. Ethanol extract of yerba mate revealed to be a potent natural antimicrobial on S. aureus, L. monocytogenes and S. enteritidis; chemical composition indicated large quantities of bioactive phenolic compounds yet activity was ineffective at pH 6. Agroindustrial residues of beet stems, peanut skin, pomace of Petit Verdot and Pinot Noir grapes, Petit Verdot grape seed, fermentation lees of red grapes and pomace of guava showed activity on S. aureus and L. monocytogenes. E. coli was not inhibited by any extracts of yerba mate or residues evaluated. Residual chemical composition showed the presence of phenolic compounds with acknowledged antimicrobial activity, demonstrating the relevance of prospective research into the natural antimicrobial properties of these sources within the food and beverage industries.

Les maladies d’Alzheimer et de Parkinson (MA et MP) sont des maladies neurodégénératives entrainant une diminution des fonctions cognitives et locomotrices et toujours dépourvues de traitements curatifs. La consommation d’huile d’olive et des polyphénols qu’elle contient atténuerait la survenue des démences telles qu’observées dans la MA ou la MP. À ce jour, ces composés phénoliques ont été étudiés de manière isolée afin de caractériser leur réactivité vis à vis des radicaux et leurs effets biologiques, mais les concentrations utilisées (5–100 µM) sont supérieures aux concentrations retrouvées dans le plasma (0.5-2,8 ng/ml). Jusqu’à présent, aucune étude n’a observé les effets de ces composés combinés, alors que l’oleuropéine et le tyrosol, des composés phénoliques parmi les plus abondants dans l’huile d’olive et que l’acide p-coumarique, un dérivé d’acide hydroxycinnamique, sont connus pour leurs activités antioxydantes et leur biodisponibilité. Dans un contexte cellulaire, les composés phénoliques agissent à travers leurs capacités de donneurs d’atomes d’hydrogène et/ou d’électrons, et impactent la régulation des défenses antioxydante. En conditions oxydatives, ils peuvent subir des modifications structurelles et mener à de nouveaux composés. L’impact cellulaire de ces derniers est encore peu étudié, car leur devenir dans le contexte d’un métabolisme oxydatif reste obscur. L’étude des métabolites issus de l’oxydation des composés phénoliques est donc d’une réelle importance afin d’approfondir les connaissances sur leurs mécanismes d’actions au niveau biologique. Nous avons émis l’hypothèse que la combinaison de l’oleuropéine, du tyrosol et de l’acide p-coumarique potentialise leurs effets neuroprotecteurs à travers leurs capacités de donneurs d’électrons et en lien avec la production des métabolites associés. Ce propose une approche pluridisciplinaire intégrant des composantes biologiques et des questions relevant de la physico-chimie, en s’appuyant sur des outils électrochimiques. En premier lieu, nous avons démontré que l’association de ces trois composés (Mix 1) permettait de potentialiser leurs effets neuroprotecteurs avec concentrations efficaces à 0.1 et 1µM, contrairement aux concentrations neuroprotectrices lorsque ces composés sont utilisés individuellement (5 à 10 fois plus élevées). Le Mix1 augmente la réactivité des composés phénoliques vis-à-vis d’espèces réactives de l’oxygène et permet une diminution de leur génération intracellulaire. Cette neuroprotection semble en partie médiée par une régulation des facteurs de régulation rédox endogènes. Dans un second temps, nous avons comparé le comportement en conditions oxydatives acellulaires de l’oleuropéine, du tyrosol et de l’acide p-coumarique individuellement et dans le Mix1. L’analyse en LC-MS2 des composés stables issus de l’oxydation du Mix 1 a montré une diminution des taux d’oxydation relatifs de chacun des composés, ainsi que la détection de trois néocomposés spécifiques de l’oxydation du Mix1. De plus, un effet neuroprotecteur significatif du Mix1 oxydé a été observé dès 1 et 5 nM, ce qui soutient l’hypothèse que les produits issus de l’oxydation des composés phénoliques peuvent participer aux effets biologiques des composés natifs. Notre troisième objectif était d’évaluer si les composés issus de l’oxydation des composés phénoliques pouvaient être générés dans un système biologique. L’analyse en LC-HRMS des extraits de cellules neuronales traitées avec le Mix1 en conditions oxydatives a révélé que ces composés étaient toujours présents sous leurs formes natives dans les cellules après plusieurs heures de traitement. Ce projet multidisciplinaire a permis d’observer les effets des composés phénoliques sous plusieurs angles. Il confirme qu’un effet neuroprotecteur de composés issus de l’oxydation est possible et ouvre la voie à de nouvelles approches pour le développement de formulations efficaces pour limiter le stress oxydatif au niveau cérébral. / Alzheimer and Parkinson diseases (AD and PD) are neurodegenerative disorders leading to cognitive function decline and curative treatments are still missing. Olive oil and related phenolic compounds consumption could prevent or slow down cognitive decline through neuronal preservation. Indeed, they have direct antioxidant properties as electrons or H-atom donors, which are largely suspected of being responsible for their biological effects, but also of some indirect properties as modulators of endogenous antioxidant defenses. The secoiridoid oleuropein and the monophenols tyrosol and p-coumaric acid have shown abilities to counteract oxidative injuries and associated neuronal death in several cellular and in vivo models. However, the basic mechanisms of action of phenolic compounds remain to be elucidated. In fact, phenolic compounds are highly sensitive to oxidative modifications and could be transformed into new compounds in an oxidative context. Cellular impacts of these products are rarely considered, probably because their intracellular detection is a great challenge and remain an important field to explore. Moreover, oleuropein, tyrosol and p-coumaric were individually evaluated in order to characterize their own reactivity towards ROS and their biological properties. However, the concentration ranges used to observe neuroprotection in cellular models (5 – 100 µM) were far from the possibly recovered phenolic concentration in plasma (0.5 - 2,8 ng /ml of plasma). To observe an effect with concentration range closer to the physiological ones, several antioxidant combinations could be proposed. Nevertheless, despite the biological promises of phenolic compounds from olive oil, studies which combined some of the most abundant phenolic compounds in the neuroprotection field is still missing. We thus hypothesized that the combination of oleuropein, tyrosol and p-coumaric acid in equimolar proportion (Mix 1) could potentiated their ROS scavenging and neuroprotective properties to counteract oxidative stress-induced neuronal death. These effects could be in part due to their oxidized metabolites. First, we demonstrated that the association of these three phenolic compounds potentiated their neuroprotective effects with efficient concentrations at 0.1 and 1µM, contrary to concentration ranges when there are used individually (5 to 10 higher). The Mix1 increase the reactivity of phenolic compounds towards ROS and decreases their intracellular production. These neuroprotective properties seems, at least in part, lead by a regulation of the endogenous redox factors. Then, we compared the behavior of Oleuropein, tyrosol and p-coumaric acid individually and in the Mix1 under acellular oxidative conditions. The oxidized Mix1 LC-ESI-MS2 profiles showed a regeneration of oleuropein through a decrease of the phenolic compounds oxidation rate and highlight the presence of specific oxidized products in Mix 1. This study also showed a significant neuroprotection of oxidized Ole and oxidized Mix1 with very low concentrations (1 and 5 nM), suggesting the putative relevant role of oxidized Ole products to protect or delay neuronal death. Our third objective was to evaluate if these oxidized metabolites could be produced in a biological system. Even under oxidative conditions, we recovered these compounds in cellular extracts under their native forms after few hours of treatments, attesting their accumulation in neuronal cells. Taking together, our results pointed out the relevance to study the phenolic compounds from a chemical and a biological point of view, which should always be as cellular redox reactions are between biological and chemical fields. Lastly, we confirmed the significance to take into account the oxidized metabolites from phenolic compounds to deeper understand their biological properties.

This diploma thesis deasl with the chemical charakterization of wine from selected PIWI varieties. The theoretical part describes the general origin and reason for breeding PIWI varieties, a closer characterization of selected three PIWI varieties, Johaniter, Hibernal and Solaris. The next part is devoted to the description of analytical methods that were used to determine the chemical characteristics. The experimental part is developed to the determination of chemical characteristics, namely general characteristics such as alcohol, total phenols, phenolic substances, volatile substances and elemental composition. The results show that are differences between wines from selected PIWI varieties in therms of chemical composition. The most represented organic acid was in the range of 735,1-1286,2mg/l malic acid. This was followed by acetic in the range of 100-400mg/l. The antioxidant activity was determined in the range of 0,2988-0,9683 mmol/l of Trollox and content of total phenols 273,5-390,3mg/l. Of the phenolic substances, gallic acid was the most represented, ranging from 6,9-13,9mg/l. As another, abundant phenolic substances, catechin in the range of 1,6-6,0mg/l was detected. Of the determined elements, phosphorus in the range of 165,4-450,5mg/l was the most represented. Representatives of ethyl ester, ethyl acetate, decanoic acid ethyl acetate and hexanoic acid ethyl ester, were detected as the most abundant volatiles. From the measured data it was evident that wines from PIWI varieties different from standard varieties, especially in the profile of aromatic substances.

The aim of this work was to compare authenticity analysis in selected food products with fruit component by using, instrumental and molekular methods. Particularly, the presence of blueberries in fruit–based foodstuffs was verified. The theoretical part is focused on the characterization, chemical composition and botanical classification of blueberries (European blueberry and Canadian blueberry). It also contains an overview of instrumental and molecular diagnostic methods that can be used for the analysis of these fruits. The experimental part focuses on the selection of a suitable method of DNA isolation, and primers for the detection of blueberries in commercial products. DNA analysis was performed by qPCR and HRM analysis. In the experimental part, DNA was isolated in sufficient quality for PCR and the presence of blueberries in foodstuffs was verified by qPCR. Using HRM analysis, we were able to differentiate between bilberry (Vaccinium myrtillus) and blueberry (Vaccinium corymbosum) in control samples and in some commercial products. Certain phenolic acids and some flavonoids specific for blueberries were detected by HPLC. The total content of polyphenols and flavonoids was determined by UV / VIS spectrophotometry.

The presented doctoral thesis is focused on the study of the biological effects of active compounds found in cereals, on the development of methods of analysis these effects, on the determination of the content of active substances and characterization of the relationship between composition and biological effects of cereals and cereal products. For the analysis several kinds of raw cereal samples (flakes, flour, germ, bran), flavored extruded cereal products and also samples of paddy and husked rice were chosen. To major types of analysed active compounds belong mainly phenolic compounds in the form of glycosides and aglycones, and also saccharides. Group parameters such as total polyphenols, flavonoids and total and reducing saccharides were determined spectrophotometrically, individual phenolics and saccharides were determined by high performance liquid chromatography (HPLC). TEAC, DPPH and CLAMS methods were used to determine the antioxidant activity. Indirect methods of determination of substances with antioxidant effect were used as well. Results of the total antioxidant activity were compared with values of antimutagenic/genotoxic activity obtained by several microbial test systems. Antimutagenic effect was expressed as a percentage of inhibition of effect of standard mutagen and could be considered as a potential preventive effect of cereals to DNA arising primarily by free radicals effect. The highest values of group and individual phenolics, antioxidant and antimutagenic activity were found in germs, bran, in buckwheat products and in coloured and raw rice. In flavoured cereal products addition of chocolate or fruit positively influences content of active phenolic substances as well as sugars, antixidant and antimutagenic activity. In a representative sample of Czech population, questionnairy study was performed to monitor interest in cereals and consumer preferences. The most of consumers consider cereals with chocolate flavour as less healthy than confirmed results of laboratory analyses. In this study some new food products were developed. Several types of model cereal products containing plant (fruit, vegetables) extracts were proposed. Extracts were added to cereals in freeze-dried and encapsulated form. The highest positive effect exhibited addition of local forrest fruit extract. Within preparation of encapsulated extracts several methods of preparing lipid or saccharides particles were also tested. The encapsulation efficiency of the methods and stability and size of particles were analysed. Optimal type of fortified cereal foods could be suggested based on the acquired results. Selected cereals were used as alternative carbon substrates (processed or raw) for the cultivation of microorganisms to produce enriched biomass usable in the feed industry. We can conclude that cereals in raw as well as processed form belong to universal foods and rich sources of biologically active substances. They can be processed by many ways. They can be used for direct consumption, as a part of new products and also undirectly as a substrate for feedstock.