Au cours de leur élevage, les animaux sont exposés à divers contaminants chimiques, qui peuvent s’accumuler au niveau des tissus animaux et être retrouvés in fine dans les produits carnés consommés par l’Homme, représentant alors un risque pour la santé des consommateurs. L’évaluation de ce risque repose classiquement sur la mesure de teneur en contaminants de la viande fraîche alors que plusieurs travaux suggèrent que seule une fraction de ces contaminants est effectivement assimilée par le consommateur du fait des transformations technologiques comme la cuisson et physiologiques comme la digestion. L’objectif de cette thèse est d’étudier ces effets modulateurs de la cuisson et de la digestion sur les contaminants chimiques de la viande et leur bioaccessibilité. En s’appuyant sur le développement d’une méthode multirésidus GC×GC-TOF/MS pour le suivi de 206 polluants environnementaux et sur des collaborations avec des Laboratoires Nationaux de Référence, le premier objectif de ce travail était d’étudier l’impact de la cuisson sur un large spectre de contaminants chimiques d’une viande intentionnellement contaminée. Les résultats montrent que la cuisson n’a pas d’impact significatif sur la teneur en PCDD/F et en métaux lourds de la viande alors que des pertes significatives (d’autant plus importantes que l’intensité de cuisson est élevée) en PCB, antibiotiques et pesticides ont pu être détectées. Ces pertes ont pour origine soit une libération dans le jus de cuisson des contaminants thermorésistants, soit une dégradation sous l’effet de la cuisson des contaminants thermosensibles, comme cela a été observé pour un antibiotique, le sulfaméthoxazole, pour lequel un schéma de dégradation thermique est proposé. Le second objectif de ce travail était d’évaluer la bioaccessibilité des contaminants chimiques de la viande en s’appuyant sur un protocole standardisé de digestion in vitro statique. Dans le cas des PCB, les résultats obtenus indiquent que la bioaccessibilité dans la viande est relativement faible (26%). La teneur initiale de la viande en matière grasse et les variations physiologiques liées à l’âge du consommateur influencent significativement ces valeurs de bioaccessibilité alors que la cuisson de la viande a moins d’influence sur la bioaccessibilité. A terme, les résultats obtenus durant ce travail devraient conduire à proposer de nouvelles procédures d’évaluation des risques liés aux contaminants chimiques de la viande, prenant en compte les modulations induites par la cuisson et la digestion. / Livestock animals are exposed to various chemical contaminants during breeding. These contaminants are rapidly transferred from the environment to animal edible tissues, thus representing a public health risk. This risk is classically assessed based on the level of contaminants in raw meat. However, due to technological processes such as cooking or physiological transformations such as digestion, only a fraction of meat contaminants can be absorbed by the body. The purpose of this PhD thesis is to investigate the modulating effect of cooking and digestion on chemical contaminants in meat and on their bioaccessibility. Thanks to a GC×GC-TOF/MS multiresidue method developed in this study for the analysis of 206 environmental pollutants and to collaborations with French National Reference Laboratories, the first aim of this work was to assess the effects of pan cooking on a broad range of chemical contaminants in spiked meat. Cooking did not impact the level of PCDD/Fs and heavy metals in meat whereas significant losses (more important as cooking conditions were more intense) of PCBs, antibiotics and pesticides were observed. These losses may originate from juice expelling of heat-resistant compounds or from degradation by breakdown of thermolabile compounds such as the sulfamethoxazole antibiotic. The second aim was to assess the bioaccessibility of chemical contaminants in meat based on a standardized in vitro static digestion. For PCBs, results showed that their bioaccessibility was low (26%). Both the meat fat content and the age of consumer significantly affect this bioaccessibility value. In contrast, meat cooking was shown to have less influence on PCB bioaccessibility. The ultimate goal of the project will be to improve chemical risk assessment procedures taking into account the changes induced by cooking and digestion on micropollutants in meat.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objectives of this work were: (1) to evaluate the nutritional and microbiological quality of common beans (Phaseolus vulgaris L.) processed with or without soaking water; (2) to analyze the sensorial traits of common bean cultivars and to compare the efficiency of quantitative descriptive analysis with not-trained and trained people; (3) to investigate the sensorial traits of common bean cultivars and to compare the efficiency of quantitative descriptive analysis with not-trained and trained people;(4) to evaluate the effect of storage under refrigeration during six months on the cooking quality, the content of minerals and the darkness of common bean cultivars with black and color tegument. Grains of Iraí and BRS Expedito beans cultivars were submitted to soaking in distilled water for eight hours, at environmental temperature. The cooking was made with the use or discard of soaking water. The minerals were determined in the grains and in the broth separately, and the microorganisms, in the mixture of grains and broth. The sensorial analysis was carried with grains of four common bean cultivars: BRS Expedito, BRS Campeiro, Iraí and Carioca. Each common bean sample was macerated for eight hours and the water was separated of the grains and placed under firing in pressure pan. The not-trained and trained people received 25 g of the four cooked cultivars and the analysis was taken using an evaluation file following the technique of Quantitative Descriptive Analysis. To evaluate the cooking time, it was used four cultivars of beans: BRS Expedito, BRS Campeiro, Pérola and Carioca and the cooking was carried through in a domestic pressure pan during 15, 20, 25 or 30 minutes. The sensorial analysis was effected in two stages: training for Qualitative Descriptive Analysis and the sensorial analysis properly, with seven trained panel. It was used six cultivars (Macanudo, Guapo Brilhante, BRS Campeiro, Pérola, Carioca and LH 5) and three times of storage (0, 3 and 6 months). It was evaluated the cooking quality (water absorption, normal and hard grains and cooking time), the mineral content and the grain clarity ( L value). According to the results, minerals composition in the grains and in the bean broth were not modified by the discarding maceration water. The bean broth presented high amount of potassium, magnesium and sulphur content. The discard of the soaking water did not improve microbiological quality of the processed common bean. Iraí and BRS Expedito cultivars may be cooked with the use or discard of soaking water because minerals content and microbiological quality of the processed common bean are maintained. The sensorial attributes texture and bean broth were evaluated with the highest experimental precision to the trained people, because lesser coefficient of variation and error mean squares were observed. The not-trained people discriminate greater number of sensorial attributes in common bean cultivars, but with a reduced amount of experimental precision. The trained group recognizes differences in the texture and broth the beans, with highest experimental precision. The panel recognized differences among the cultivars such as: uniformity tegument color, hardness, graininess, broth color and viscosity. The rupture of the tegument of the grains was bigger as it was increased the cooking time. The hardness and the graininess received best notes as longer as the cooking time of the common bean. The use of 20 the 25 minutes to cook in domestic pressure pan seems to identify black and carioca cultivars of common bean with the best evaluation profile, besides keeping the integrity of the cooked grains. Beans storage for six months reduces the grains capacity of water absorption and influences negatively in the darkness of Carioca group. However, it does not increase the amount of hardshell grains and the cooking time, as well as the minerals content of the grains. / Os objetivos desse trabalho foram: (1) analisar se o processamento do feijão deve ser realizado com o aproveitamento ou não da água de maceração, visando à manutenção da qualidade nutricional e microbiológica; (2) avaliar o perfil sensorial de cultivares de feijão e comparar a eficiência da técnica de análise descritiva quantitativa com avaliadores nãotreinados e treinados; (3) investigar o tempo de cozimento que deverá ser utilizado, em panela de pressão doméstica, para a identificação de cultivares de feijão de grãos preto e carioca com atributos sensoriais de melhor perfil para o consumo; (4) avaliar o efeito do armazenamento sob refrigeração (temperatura de 0 ºC e umidade relativa do ar de 50%) ao longo de seis meses sobre a qualidade para o cozimento, o teor de minerais e a claridade dos grãos de feijão de cultivares de tegumento preto e de cor. Grãos das cultivares de feijão Iraí e BRS Expedito foram submetidos à embebição em água destilada por oito horas, à temperatura ambiente. O cozimento foi realizado com e sem o aproveitamento da água de maceração. Os minerais foram determinados nos grãos e no caldo, separadamente, e os microrganismos, na mistura de grãos e caldo. Para a avaliação do perfil sensorial, grãos de quatro cultivares de feijão: (BRS Expedito, BRS Campeiro, Iraí e Carioca) foram submetidos à análise sensorial por avaliadores treinados e não-treinados. As amostras de feijão, de cada cultivar, foram maceradas por oito horas e colocadas sob cocção em panela de pressão. Os avaliadores não treinados e os treinados receberam 25 g de feijão cozido, de cada uma das quatro cultivares. A análise foi realizada com o auxílio de uma ficha de avaliação e utilizou-se a técnica da 14 Análise Descritiva Quantitativa (ADQ). Para se avaliar o tempo de cozimento, utilizaram-se grãos de quatro cultivares de feijão: BRS Expedito, BRS Campeiro, Pérola e Carioca, os quais foram submetidos ao cozimento em panela de pressão doméstica por 15, 20, 25 ou 30 minutos e em seguida realizou-se uma análise sensorial com avaliadores treinados. Seis cultivares (Macanudo, Guapo Brilhante, BRS Campeiro, Pérola, Carioca e LH 5) e três tempos de armazenamento dos grãos (0, 3 e 6 meses) foram avaliados quanto à qualidade para o cozimento (absorção de água, grãos normais, grãos hardshell e tempo de cozimento), o teor de minerais e a coloração dos grãos (valor de L ). Os resultados obtidos evidenciaram que a composição de minerais nos grãos e no caldo de feijão não foi alterada pelo descarte da água de maceração para o cozimento. O caldo de feijão apresentou altos teores de fósforo, potássio, magnésio e enxofre. A eliminação da água de maceração não melhorou a qualidade microbiológica do feijão processado. O cozimento das cultivares de feijão Iraí e BRS Expedito pode ser realizado com o aproveitamento ou com o descarte da água de maceração, pois há manutenção do teor de minerais e da qualidade microbiológica do feijão. Em relação ao perfil sensorial, os avaliadores reconheceram diferenças para as cultivares de feijão quanto à uniformidade da cor do tegumento, à dureza, à granulosidade, à cor do caldo e à viscosidade. Os atributos sensoriais textura e caldo foram avaliados com maior precisão experimental pelos avaliadores treinados, enquanto que os avaliadores não-treinados diferenciaram maior número de atributos sensoriais nas cultivares de feijão, mas com menor precisão experimental. Em relação aos diferentes tempos de cocção observou-se que a ruptura no tegumento dos grãos foi maior à medida que se aumentou o tempo de cozimento. A dureza e a granulosidade receberam melhores notas quanto maior foi o tempo de cozimento dos grãos de feijão. A utilização de 20 a 25 minutos de cozimento em panela de pressão doméstica possibilita a identificação de cultivares de feijão de grãos preto e carioca com o melhor perfil para o consumo, mantendo a integridade dos grãos cozidos. O armazenamento de feijão por seis meses reduz a capacidade de absorção de água de algumas cultivares e influencia negativamente na claridade dos grãos do tipo Carioca. Entretanto, não aumenta a porcentagem de grãos hardshell e o tempo de cozimento, além disso, não altera o teor de minerais dos grãos avaliados após seis meses de armazenamento.