This diploma thesis deals with the stability and basic properties of combined beverages and fruit concentrates. The theoretical part describes the production and use of fruit concentrates. Furthermore, the work deals with anthocyanic pigments and phenolic substances. The principle and instrumentation of liquid chromatography and electron paramagnetic resonance were described. In the next subchapter, the methods of determination of total anthocyanins and phenolic substances were described. The experimental part of the thesis described the determination of soluble solids, viscosity and antioxidant activity. The total content of phenolic compounds were determined by the Folin-Ciocalteua method and the total anthocyanins were determined by the pH-differential method. In the samples were determined cyanidine-3-glucoside and cyanidin-3-galactoside by liquid chromatography.

The discovery and dissemination of new knowledge are essential in food science. To advance our understanding of fruit chemistry, analytical methods were compared and applied. Polyphenols are secondary metabolites in fruits of particular importance in food science, as they contribute to the sensory attributes and health benefits of the products. Evaluation of common analytical methods for the quantification of polyphenols, including the Folin-Ciocalteu (F-C), Lowenthal permanganate (L-P), 4-dimethylaminocinnamaldehyde (DMAC) and the bovine serum albumin (BSA) precipitation methods, was conducted using analytical method validation procedures. The F-C method was not specific to polyphenols, and the L-P method had the widest working range but lacked accuracy. The DMAC method was the most specific to flavanols, and the BSA method was not suitable for quantification of smaller flavanols. Quantitative performance of these four methods was evaluated using a broad range of fruit-derived samples. Variation in quantitative results obtained using these four methods was explained by differences in polyphenol and matrix composition of these samples and differences in operating principles of the methods. The reactivity of individual polyphenol compounds (catechin, epicatechin, PC B2, PC pentamer, chlorogenic acid, phloretin, and quercetin) to the polyphenol and flavanol quantification results using Prussian blue (P-B), F-C, DMAC and BSA precipitation methods were also assessed and determined to differ by up to thirteen-fold, depending on the assay. Furthermore, the contribution and interactions of polyphenol compounds (catechin, PC B2, and chlorogenic acid) and potentially interfering compounds likely to be found in fruit and fruit products (ascorbic acid, glucose, and SO2) to the quantitative results of these methods were evaluated using a full factorial design. Significant interactions among polyphenol compounds, and among the interfering compounds were found. The standardized coefficient (β) for all factors and interactions of polyphenol compounds varied from 0.347 to 129, and from near 0 to -46.8 for all factors and interactions of interfering compounds. Our findings indicate that the choice of standards, polyphenol and matrix composition of the sample may cause disparity among the quantitative results of these methods. Amino acids in apple (Malus × domestica Borkh.) juice not only influence the quality of fermented cider through fermentation kinetics but also impact the flavor of the cider through yeast metabolism. Due to recent advances in analytical instrumentation, amino acids profiles in apple juice were determined much faster and more accurately than by previously applied methods. Twenty amino acids were quantified by UPLC-PDA in juices from 13 apple cultivars grown in Virginia. The relative amino acid profile was significantly different among the apple juices evaluated. The total amino acid concentration ranged from 18 mg/L in Blacktwig juice to 57 mg/L in Enterprise juice. L-Asparagine, L-aspartic acid and L-glutamine are the principal amino acids observed in most apple juices. These results will inform future research on yeast metabolism and nitrogen management during cider fermentation. To better disseminate knowledge gained through research to the next generation of food scientists, the effectiveness of new instructional technology—a cellphone-based personal response system—in food science education was evaluated. Students' academic performance was improved by the incorporation of this technology into lectures, and its use was well perceived by the students (easy to use and positively impacted their learning). This finding contributes to the scholarship of teaching and learning in food science by providing useful insight into the potential for application of such tools with improved student engagement and learning outcomes. Advances in food chemistry research will enable the development of value-added food products, and the pedagogical advancement in food science education will better convey new and existing knowledge to students, who will apply this knowledge to promote a safe and nutritious food supply that enhances human health and increases the value of specialty crops. / Doctor of Philosophy / In food science, both the discovery and dissemination of new knowledge are essential. To advance our understanding in fruit chemistry, several analytical methods were compared and applied. Polyphenols are important bioactive compounds in fruits associated with health benefits, and they also contribute to the bitterness and astringency of the products such as chocolate and red wines. Systematic evaluation of common analytical methods used to quantify polyphenols was conducted. When different methods were used to evaluate a broad range of fruit-derived samples, different results were obtained for a given sample, depending on the method applied. This was explained by the difference in polyphenol composition of these samples. Furthermore, different individual polyphenol compounds contributed differently to quantitative results for these methods. Interactions among polyphenol compounds and interference from constituents of the juice samples other than polyphenols were also found. These findings demonstrate that when comparing fruit chemistry (polyphenol concentration) results obtained using the methods evaluated, it is necessary to consider the polyphenol composition as well as the sample matrix composition. This knowledge will improve our ability to interpret and compare existing data on polyphenol content in fruits, advancing the understanding the polyphenols and health and informing producers to improve their fruit products with optimized quality and sensory characters. Secondly, amino acids in apple juice influence the quality of fermented cider, through not only controlling the fermentation rate, but also impacting the flavor of the cider through yeast metabolism. Twenty amino acids were quantified in juices from 13 apple cultivars grown in Virginia with potential use in cider making using a recently developed method in analytical chemistry. The relative amino acid profile was significantly different among the apple juices evaluated. L-Asparagine, L-aspartic acid and L-glutamine are the principal amino acids observed in most apple juices. This knowledge will help with the development of fermentation strategies for production of ciders with targeted sensory attributes. To better disseminate new knowledge in food science to the next generation, the effectiveness of a new educational technology application—a cellphone-based personal response system (similar to clickers)—in food science education was evaluated. Using this application during lecture resulted in improved quiz grades, and students felt that it was easy to use and positively impacted their learning. This application has the potential to improve effectiveness of lectures in higher education classrooms. Advances in food chemistry research will enable development of value-added food products, and the pedagogical advancement in food science education will better convey new and existing knowledge to students, who will apply this knowledge to promote a safe and nutritious food supply that enhances human health and increases the value of specialty crops.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O amendoim A. hypogaea L. é a quarta oleaginosa mais consumida no mundo e suas sementes são altamente energéticas, com grandes quantidades de lipídios, proteínas, vitaminas e carboidratos. Diversas atividades farmacológicas já foram observadas em extratos de raízes, folhas e sementes, sendo a principal delas a atividade antioxidante. Neste trabalho, foi realizada a comparação entre duas metodologias (por maceração e assistida por micro-ondas) para a extração de compostos antioxidantes, incluindo o resveratrol. Também foi realizada a comparação entre extratos de diferentes órgãos de cultivares brasileiras (IAC 886, IAC Caiapó, IAC Tatu ST, IAC 8112 e IAC 99-1) quanto à atividade antioxidante, por DPPH, ao teor de compostos fenólicos, por Folin-Ciocalteu, e ao teor de resveratrol, por HPLC. Por fim, foram estabelecidos protocolos de cultura de tecidos para explantes de sementes, visando à produção de calos e plantas in vitro para posterior dosagem de compostos de interesse, tendo em vista a possibilidade de modulação das condições in vitro. As melhores condições determinadas para a extração por maceração de antioxidantes de A. hypogaea foram 80% de etanol em água como solvente, trituração com almofariz e pistilo, 50 mL solvente por grama de material vegetal seco, 120 minutos de incubação e dois estágios de extração. As melhores condições para a extração de resveratrol assistida por micro-ondas foram o uso de 37 mL de solvente/g material vegetal seco, com agitação de 1200 rpm por 15 minutos, a 37C. De uma maneira geral, os extratos de raízes e oriundos de micro-ondas apresentaram maior atividade antioxidante (até 92,36 2,71%), teor de compostos fenólicos (até 54,15 1,39 mg EAG/g extrato) e teor de resveratrol (até 1,614 0,356 mg/g extrato). Dentre as cultivares estudadas, IAC Tatu e IAC 99-1 foram as que apresentaram os teores mais elevados. Brotos e calos friáveis foram obtidos a partir de cotilédones, eixos embrionários e folíolos embrionários cultivados em meios suplementados com BAP e picloram, respectivamente. / Peanut A. hypogaea L. is the fourth most consumed oleaginous in the world and its seeds are high energetic, with high amounts of lipides, proteins, vitamins and carbohidrates. Several pharmacological activities have been observed in extracts of roots, leaves and seeds, especially an antioxidant activity. In this work, the comparison between two extraction methodologies (by maceration and microwave assisted extraction) for the extraction of antioxidant compounds, including resveratrol, was studied. We also carried out a comparison between extracts from different organs of Brazilian cultivars (IAC 886, IAC Caiapó, Tatu ST IAC, IAC 8112 and IAC 99-1) for antioxidant activity by DPPH, the content of phenolic compounds by Folin-Ciocalteu and the resveratrol content by HPLC. Finally, we established tissue culture protocols for seed explants, aiming at the production of in vitro plant material for future measurement of compounds of interest in the view of possible modulation of in vitro conditions. The best conditions for the extraction of antioxidant from A. hypogaea compounds by maceration were 80% of ethanol in water as a solvent, trituration by mortar and pestle, 50 mL solvent/g dry plant, 120 minutes of incubation and two stages of extraction. The best conditions for the extraction of resveratrol assisted by micro-wave were the use of 37 mL of solvent for each gram of dry plant, with 1200 rpm of agitation for 15 minutes, with 37oC. In general, root extracts and assisted by microwave showed higher antioxidant activity (until 92,36 2,71%), phenolic (untill 54,15 1,39 mg AGE/g extract) and resveratrol content (untill 1,614 0,356 mg/g extract). Among the studied cultivars, IAC Tatu and IAC 99-1 showed the best results. In tissue culture, shoots and friable calli were obtained from cotiledons, embryonic axis and embryonic leaflet cultured in media supplemented with BAP and picloram, respectively.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O amendoim A. hypogaea L. é a quarta oleaginosa mais consumida no mundo e suas sementes são altamente energéticas, com grandes quantidades de lipídios, proteínas, vitaminas e carboidratos. Diversas atividades farmacológicas já foram observadas em extratos de raízes, folhas e sementes, sendo a principal delas a atividade antioxidante. Neste trabalho, foi realizada a comparação entre duas metodologias (por maceração e assistida por micro-ondas) para a extração de compostos antioxidantes, incluindo o resveratrol. Também foi realizada a comparação entre extratos de diferentes órgãos de cultivares brasileiras (IAC 886, IAC Caiapó, IAC Tatu ST, IAC 8112 e IAC 99-1) quanto à atividade antioxidante, por DPPH, ao teor de compostos fenólicos, por Folin-Ciocalteu, e ao teor de resveratrol, por HPLC. Por fim, foram estabelecidos protocolos de cultura de tecidos para explantes de sementes, visando à produção de calos e plantas in vitro para posterior dosagem de compostos de interesse, tendo em vista a possibilidade de modulação das condições in vitro. As melhores condições determinadas para a extração por maceração de antioxidantes de A. hypogaea foram 80% de etanol em água como solvente, trituração com almofariz e pistilo, 50 mL solvente por grama de material vegetal seco, 120 minutos de incubação e dois estágios de extração. As melhores condições para a extração de resveratrol assistida por micro-ondas foram o uso de 37 mL de solvente/g material vegetal seco, com agitação de 1200 rpm por 15 minutos, a 37C. De uma maneira geral, os extratos de raízes e oriundos de micro-ondas apresentaram maior atividade antioxidante (até 92,36 2,71%), teor de compostos fenólicos (até 54,15 1,39 mg EAG/g extrato) e teor de resveratrol (até 1,614 0,356 mg/g extrato). Dentre as cultivares estudadas, IAC Tatu e IAC 99-1 foram as que apresentaram os teores mais elevados. Brotos e calos friáveis foram obtidos a partir de cotilédones, eixos embrionários e folíolos embrionários cultivados em meios suplementados com BAP e picloram, respectivamente. / Peanut A. hypogaea L. is the fourth most consumed oleaginous in the world and its seeds are high energetic, with high amounts of lipides, proteins, vitamins and carbohidrates. Several pharmacological activities have been observed in extracts of roots, leaves and seeds, especially an antioxidant activity. In this work, the comparison between two extraction methodologies (by maceration and microwave assisted extraction) for the extraction of antioxidant compounds, including resveratrol, was studied. We also carried out a comparison between extracts from different organs of Brazilian cultivars (IAC 886, IAC Caiapó, Tatu ST IAC, IAC 8112 and IAC 99-1) for antioxidant activity by DPPH, the content of phenolic compounds by Folin-Ciocalteu and the resveratrol content by HPLC. Finally, we established tissue culture protocols for seed explants, aiming at the production of in vitro plant material for future measurement of compounds of interest in the view of possible modulation of in vitro conditions. The best conditions for the extraction of antioxidant from A. hypogaea compounds by maceration were 80% of ethanol in water as a solvent, trituration by mortar and pestle, 50 mL solvent/g dry plant, 120 minutes of incubation and two stages of extraction. The best conditions for the extraction of resveratrol assisted by micro-wave were the use of 37 mL of solvent for each gram of dry plant, with 1200 rpm of agitation for 15 minutes, with 37oC. In general, root extracts and assisted by microwave showed higher antioxidant activity (until 92,36 2,71%), phenolic (untill 54,15 1,39 mg AGE/g extract) and resveratrol content (untill 1,614 0,356 mg/g extract). Among the studied cultivars, IAC Tatu and IAC 99-1 showed the best results. In tissue culture, shoots and friable calli were obtained from cotiledons, embryonic axis and embryonic leaflet cultured in media supplemented with BAP and picloram, respectively.

Ce travail de thèse s'attache à identifier des plantes et/ou molécules à activités cytotoxique, antioxydante, anti-inflammatoire et antivirale ciblant le virus du chikungunya (CHIKV) dans le but de trouver des alternatives thérapeutiques vis-à-vis du stress oxydatif et de l'inflammation, mécanismes impliqués dans les maladies chroniques non transmissibles (diabète, obésité…), et de la maladie du chikungunya, maladie vectorielle réémergente. La première partie de ces travaux présente les résultats obtenus lors d'un criblage d'activités biologiques réalisé sur une sélection de dix-huit plantes endémiques et indigènes de La Réunion. Les activités ciblées ont été les activités cytotoxiques sur une lignée cellulaire humaine (cellules THP-1), les activités antioxydantes évaluées par un test in cellulo d'hémolyse et par quatre tests chimiques (TEAC/DPPH/FRAP/ORAC) ainsi qu'une évaluation de la teneur en composés phénoliques (test FOLIN) et les activités anti-inflammatoires testées sur des macrophages murins (cellules RAW-BlueTM). Les résultats obtenus ont permis de mettre, plus particulièrement, en évidence les activités de différents extraits : cytotoxique pour Carissa spinarum, antioxydantes pour Agarista buxifolia et Dryopteris wallichiana et anti-inflammatoire pour Stillingia lineata et Indigofera ammoxylum. La deuxième partie du travail est consacrée à l'étude phytochimique d'une espèce indigène de La Réunion, Stillingia lineata, choisie en raison des résultats obtenus lors de ce criblage biologique préliminaire et de ceux du programme Phytochik. Un fractionnement bioguidé par un test antiviral, réalisé sur des cellules Vero (cellules rénales de singe vert Cercopithecus aethiops) contaminées par le CHIKV, a conduit à l'isolement de trois macrocycles diterpéniques rares de type tonantzitlolone dont l'un présente une structure non caractérisée jusque-là, et d'un pimarane de structure nouvelle. La 4'-acétoxytonantzitlolone a été identifiée comme molécule candidate contre le CHIKV (CE50 = 7 μM). Des relations structure-activité ont pu être définies ; la présence d'un groupement oxygéné sur la chaîne latérale des tonantzitlolones semble jouer un rôle important sur la réponse antivirale de ces squelettes diterpéniques. / The aims of this PhD work were to identify plants and/or molecules with cytotoxic, antioxidant, anti-inflammatory or antiviral (chikungunya virus , CHIKV) activities in order to find therapeutic alternatives towards oxidative stress and inflammation, mechanisms involved in chronic noncommunicable diseases (diabetes, obesity ...), and chikungunya disease, reemerging vector-borne disease. The first part of this work presents the results obtained from a biological screening carried out on a selection of eighteen endemic and indigenous plants of La Réunion. The targeted activities were cytotoxicity on a human cell line (THP-1), antioxidant activities evaluated using an in cellulo hemolysis assay and four chemical tests (TEAC / DPPH / FRAP / ORAC) together with an evaluation of the content of phenolic compounds (FOLIN test) and anti-inflammatory activity tested in murine macrophages (RAW cells-BlueTM). The results allowed to highlight activities of different extracts in particular : cytotoxic for Carissa spinarum, antioxidant for Dryopteris wallichiana and Agarista buxifolia and anti-inflammatory for Stillingia lineata and Indigofera ammoxylum.The second part of this work is devoted to the phytochemical study of Stillingia lineata, an indigenous species of La Réunion chosen because of the results obtained in this preliminary biological screening and those carried out in Phytochik programme. Bioassay-guided fractionation performed on Vero cells (green monkey kidney cells Cercopithecus aethiops) infected with CHIKV led to the isolation of three rare macrocycle-type diterpenes called tonantzitlolone and a new pimarane. The 4'-acetoxytonantzitlolone was identified as a candidate molecule against CHIKV (EC50 = 7 μM). Structure-activity relationships have been defined, the presence of an oxygenated group on the side chain of tonantzitlolones seems to play an important role in the antiviral response of the diterpene skeleton.