Cette thèse porte sur l’éco-extraction et l’encapsulation de pigments naturels pour une exploitation et application dans les industries alimentaire, cosmétique et pharmaceutique. Dans ce but, l'extraction assistée par micro-ondes (MAE) ou par ultrasons (UAE) et celle par liquides ioniques (LI) ont été évaluées pour l'extraction de caroténoïdes et d'anthocyanes de plantes vietnamiennes. Les résultats obtenus montrent que le MAE a été un système permettant d'accélérer et d'améliorer tous les types d'extraction testés alors que les ultrasons se sont montrés particulièrement efficaces lorsque les pigments étaient présents à la surface des tissus végétaux. Cependant, l’UAE améliore également les résultats par rapport à des extractions sans assistance. Les LI classiques ne sont pas adaptés pour l’extraction des pigments caroténoïdes et anthocyaniques qui sont généralement non volatils et thermosensibles car il n'a pas été possible de séparer les pigments extraits des LI dans des conditions douces. Pour remédier à ce problème, des LI réversibles ont été évalués. Le DBU/ 1-hexanol était efficace pour extraire les caroténoïdes relativement accessibles, mais, en raison d'une viscosité élevée, il perdait son efficacité pour d'autres tissus. La deuxième partie de cette thèse concerne l’encapsulation d’anthocyanes d’hibiscus dans des levures. Nous avons d’abord travaillé avec des levures entières. Les résultats ont montré que les cellules de levure étaient un bon matériau pour l'encapsulation des anthocyanes. Cependant, pour les levures non désactivées, les enzymes ont provoqué une perte indésirable de couleur des anthocyanines pendant le stockage. Les microparticules de levures traitées thermiquement ont montré un effet protecteur élevé pendant le stockage. Puis, comme les anthocyanes étaient majoritairement encapsulées dans le réseau pariétal des levures, nous avons utilisé les écorces de levures séparées du reste des cellules. Les microparticules des écorces de levure ont apporté une bonne protection pour les anthocyanes contre l'humidité, la chaleur et la lumière. En comparant avec les microparticules de maltodextrine, celles des écorces de levure étaient plus stables dans des conditions d'humidité élevée. En général, les microparticules de levure ont montré une capacité à protéger les anthocyanes et à garder la couleur rouge de la poudre d’anthocyanes encapsulées. Ces résultats montrent que la poudre d’anthocyanes encapsulées dans des levures ou écorces de levure a un avenir prometteur pour être appliquée dans les industries alimentaire, cosmétique et pharmaceutique. / This thesis deals with extraction processes using assistance technologies or green solvents and encapsulation systems of natural pigments in order to exploit and apply them in the food, cosmetic and pharmaceutical industries. In this goal, microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE) and Ionic liquids (IL) were evaluated for the extraction of carotenoids and anthocyanins from Vietnamese plants. The results obtained show that the MAE was always a rapid and helpful system for all types of extraction tested whereas ultrasounds were particularly efficient when pigments are present on the surface of plant tissues. However, UAE was also improving results compared to conditions without assistance. Traditional IL are not suitable for the extraction of carotenoid and anthocyanin pigments that are generally non-volatile and heat-sensitive because it has not been possible to separate pigments extracted from IL under mild conditions. Therefore switchable IL were evaluated. DBU/ 1-hexanol was efficient to extract carotenoids that were relatively accessible, but, due to its high viscosity, it lost efficacy for other tissues. The second part of this thesis concerns the encapsulation of Hibiscus anthocyanins in yeasts. We have first worked with whole yeast cells. The results showed that yeast cells were a good material for the encapsulation of anthocyanins. However, yeast enzymes caused undesirable colour loss of anthocyanin during storage. Microparticles of heat-treated yeasts showed a high protective effect during storage. Then, as it was interesting to keep the pigments in the cell wall and deactivate the yeast enzymes, we used yeast hulls. Yeast hull particles brought a good protection to anthocyanins against moisture, heat and light. In comparison with maltodextrin microparticles, yeast hull ones were more stable in high humidity. In general, yeast microparticles have shown an ability to protect anthocyanins and to keep the red color of encapsulated anthocyanin powder. These results show that yeast encapsulated anthocyanins powder has a promising future to be applied in the food, cosmetic and pharmaceutical industries.

Cette thèse s’inscrit dans le cadre du projet SMILE de Microphyt qui vise à proposer une gamme d’ingrédients naturels issus de microalgues afin de répondre à deux enjeux sociétaux majeurs : le surpoids/obésité et le déclin des fonctions cognitives liées à l’âge (DCLA). Les acides gras polyinsaturés oméga-3 (AGPI-w3) et la fucoxanthine (Fx) ont des activités prouvées contre les voies métaboliques liées à la prise de poids et aux DCLA. C’est dans ce contexte que les efforts se sont tout d’abord focalisés vers la sélection de deux espèces de microalgues brunes dont le critère principal a été la productivité en ces molécules d’intérêts. Deux souches des espèces Tisochrysis lutea et Phaeodactylum tricornutum ont alors été sélectionnées du fait de leurs fortes teneurs et productivités en AGPI-w3 et Fx, pour être par la suite cultivées à l’échelle de 5000 L dans des photobioréacteurs (PBR) industriels Camargue©. Dans un second temps, les travaux ont porté sur l’optimisation des procédés post-culture pour les deux espèces, c’est-à-dire, de la récolte de la biomasse à l’obtention d’un extrait, afin de garantir la sécurité, la stabilité et l’efficacité des produits finis. L’étude des procédés de récolte/concentration de la culture a montré leur influence sur les classes lipidiques et l’apparition d’acides gras sous forme libre (AGL), engendrés par les stress mécaniques et thermiques subis par la biomasse lors de cette étape. La formation de ces AGL a pu être limitée par l’utilisation de la filtration tangentielle et de la centrifugation dans certaines conditions. De plus, le lien entre procédé et activité a été souligné via une étude sur modèle cellulaire CaCo2 : les AGL pourraient être à l’origine d’une cytotoxicité accrue des extraits. Enfin, l’optimisation des conditions de co-extraction des AGPI-w3 et de la Fx a abouti à la sélection d’un solvant éco-compatible (éthanol) et a mis en lumière le fort impact de la granulométrie et du ratio solvant/biomasse sur les rendements d’extractions. / This thesis is part of Microphyt's SMILE project, which aims to propose a range of natural ingredients derived from microalgae. The main objective of this project is to respond to two major societal issues: overweight/obesity and the decline of age-related cognitive functions (DCLA). Omega- 3 polyunsaturated fatty acids (PUFAs) and fucoxanthin (Fx) have proven activities against the metabolic pathways associated with weight gain and DCLA. In this context, the first efforts were initially directed towards the selection of two species of brown microalgae with their productivity in these molecules of interest as the main criterion. Two strains of the species Tisochrysis lutea and Phaeodactylum tricornutum were then selected as raw materials rich in PUFAs and Fx and were grown at a 5,000 L scale in Camargue© photobioreactors. The work then focused on optimizing the downstream processing steps to the cultivation of microalgae in order to guarantee the safety, stability and efficiency of the final products. Harvesting processes had, in particular, through the mechanical stress generated, an impact on lipid classes and the appearance of free fatty acids (FFA) in the studied species. A CaCo2 cell model study has suggested that FFA may be responsible for increased cytotoxicity of extracts. The formation of FFA during the concentration stage could be limited by the use of tangential filtration and centrifugation under certain conditions. Finally, the optimization of the co-extraction conditions of PUFAs and Fx resulted in the selection of an eco-friendly solvent (ethanol) and highlighted the strong impact of particle size and solvent/biomass ratio on extraction yields.

A expansão do consumo de alimentos submetidos a elevado grau de processamento em países em desenvolvimento é notória. Em paralelo, observa-se o aumento na prevalência de excesso de peso e de comorbidades associadas. O fenômeno também tem sido observado em famílias consideradas pobres que recebem benefício financeiro de programa federal de transferência condicionada de renda. O objetivo geral foi analisar o consumo alimentar de beneficiários do Programa Bolsa Família (PBF). Foi elaborado um sistema de classificação de alimentos, de acordo com o propósito e grau de processamento. Os dados utilizados são provenientes do módulo de consumo alimentar pessoal da Pesquisa de Orçamentos Familiares (n = 34.003; 7.600 beneficiários), conduzida pelo Instituto Brasileiro de Geografia e Estatística (IBGE) entre os anos de 2008 e 2009. As observações foram classificadas em três faixas etárias: crianças e adolescentes (10 a 18 anos), adultos (19 a 59 anos) e idosos (60 ou mais anos). Os integrantes da amostra também foram discriminados de acordo com o local do domicílio: regiões Norte, Sul, Nordeste, Centro-Oeste, estado de São Paulo e grupamento dos estados de Minas Gerais, Rio de Janeiro e Espírito Santo. Para estimar o conteúdo de carotenoides presente na dieta um banco de dados foi construído e a composição dessas substâncias nos alimentos foi obtida, prioritariamente, em fonte de dados nacional. Foram levadas em conta as distintas formas de preparo. A ingestão de energia, macronutrientes, fibra alimentar, vitaminas e minerais também foi analisada, com base nas composições dos alimentos divulgadas pelo IBGE. O IMC foi calculado e regressões múltiplas ajustadas aos dados, controlando fatores socioeconômicos e demográficos. Notou-se, destacadamente, que a energia fornecida pelos alimentos ultraprocessados torna-se menor para faixas etárias de maior idade. As pessoas beneficiárias do programa apresentaram tendência para obtenção de menor proporção de energia proveniente desses produtos. A ingestão de fibra alimentar foi, em geral, reduzida (exceto para beneficiários do sexo masculino), assim como de ácidos graxos poli-insaturados, e os ácidos graxos trans foram consumidos em excesso. Verificou-se conteúdo insuficiente (valores médios) de vitaminas E, A, D, folato, B1 (em idosas) e B6 (em idosos), cálcio, potássio, magnésio e fósforo (em meninos e meninas). O sódio foi consumido em excesso. As principais fontes dietéticas da maioria dos minerais foram alimentos minimamente processados e in natura, com exceção do sódio e do manganês. Alimentos processados e preparações culinárias (sem alimentos ultraprocessados na receita) foram importantes fontes de vitaminas C, D e do complexo B, mas também de colesterol, lipídeos e ácidos graxos saturados. A elevada quantidade de ácidos graxos trans contida em alimentos ultraprocessados foi notada. O conteúdo estimado de carotenoides na dieta foi baixo e não integrou intervalos preconizados como seguros. Destacaram-se como fontes dessas substâncias, além das frutas, legumes e verduras, o macarrão preparado com molho de tomate (para licopeno) e as sopas (para ?-caroteno e pró-vitamínicos A). Não foi captado efeito estatisticamente positivo, no IMC, da participação das categorias de alimentos. / The population\'s growing demand for high processed foods in developed countries is well known. At the same time, it is noted an increase of the prevalence of excess body weight and associated comorbidities. The fact has have also been observed among poor families that receive financial support from federal conditional cash transfer programs. The general aim of this thesis was to analyze food consumption of \"Bolsa Família\" Program (BFP) beneficiaries. A food classification system was developed, according to the purpose and processing level. The data used is from the individual food consumption module of a household expenditure survey (n = 34,003; 7,600 beneficiaries) carried out by Brazilian Institute of Geography and Statistics (BIGS) between 2008 and 2009. Observations were classified in three age strata: children and adolescents (10 to 18 years old), adults (19 to 59 years old) and elderly (60 years old or older). They were also identified according to the geographic regions or states where they live in: North, South, Northeast, Center-West, São Paulo state, and the group of Minas Gerais, Rio de Janeiro and Espírito Santo states. To estimate carotenoid intake in the diet, a database was built and food composition of these bioactive compounds were obtained, with priority, in a national database, and the distinct modes of preparation were considered. The ingestion of energy, macronutrients, vitamins, minerals and dietary fiber was analyzed as well, but according to food composition data from BIGS. The BMI was calculated and multiple regressions were fitted to data, controlling socioeconomic and geographic variables. Amidst the results, it was noted that the higher is the share of ultra-processed foods, expressed as energy intake, the lower is the age strata. BFP beneficiaries tend to obtain lower proportions of energy intake by these foods. In general, the ingestion of dietary fiber (except for men) and polyunsaturated fatty acids was considered low and the consumption of trans fatty acids was high. The amounts (average values) of vitamins E, A, D, folate, B1 (for elderly women) e B6 (for elderly men), calcium, potassium, magnesium and phosphorus (for children and adolescents) were evaluated as low. On the other hand, the sodium intake was expressively high. The main dietary sources of the majority of minerals were minimally processed or in natura foods, except for sodium and manganese. Processed foods and culinary preparations (without ultra-processed foods in their recipes) were important sources of vitamins C, D and B-vitamins, but of cholesterol, lipids and saturated fatty acids as well. The proportion of trans fatty acids obtained in ultra-processed foods was notable. Carotenoid intake in the diet did not fit into Prudent individual daily range intake, and the main sources of these phytochemicals were, beside fruits and vegetables, pasta prepared with tomato sauce (for lycopene) and soups (for ?-carotene and provitamin A carotenoids). No statistically significant effect from the share of energy obtained by foods, categorized into groups, was observed on BMI.

Ce travail de thèse porte sur l’étude de l’effet du traitement par champs électriques pulsés (CEP) sur différents procédés de séchage et de friture à partir de produits végétaux (pommes de terre et carottes). Les interactions entre différents modes de séchage et de prétraitement ont été étudiées. L’impact du traitement par CEP et du pré-séchage par l’air chaud ou pré-séchage par le vide sur la cinétique de friture et sur la qualité des produits frits ont été analysés. Le prétraitement par CEP entraîne une électro-perméabilisation des membranes cellulaires, ce qui favorise l’accélération des cinétiques de perte en masse (humidité). Les résultats montrent que le temps de séchage a été réduit significativement dans tous les procédés étudiés (séchage par l’air chaud, séchage par microonde, séchage sous vide). L’avantage du traitement par CEP se manifeste également par une diminution au niveau de la température interne du produit séché. Cette température basse présente un avantage notable dans la préservation des composés sensibles à la chaleur (caroténoïdes…). La couleur des échantillons prétraités par CEP puis séchés, gardent mieux la coloration initiale et présente une déviation réduite en termes de couleur après réhydratation. En ce qui concerne le procédé de friture, l’application du traitement par CEP montrent un avantage en termes de temps de friture mais également en termes de la teneur en huile absorbée. En effet, cette teneur en huile est moins élevée pour le cas des échantillons traités électriquement comparés aux échantillons non traités. La combinaison du CEP et du pré-séchage à l’air chaud (ou du pré-séchage sous vide) montre une réduction importante du temps de friture et également en terme de teneur en huile absorbée. / This research project focuses on the effect of pulsed electric field (PEF) treatment on various drying and frying processes from plant products (potatoes and carrots). Interactions between different drying modes and pretreatment have been studied. The impact of PEF treatment and pre-drying by hot air or pre-drying by vacuum drying on frying kinetics and the quality of fried products were analyzed. PEF pretreatment results in electro-permeabilization of the cell membranes, which favors the acceleration of mass transfer processes. The results showed that the drying time was significantly reduced in all processes (hot air drying, microwave drying, vacuum drying). The advantage of the PEF treatment was also manifested by a decrease of the internal temperature of the product during drying. This lower temperature has a significant advantage in the preservation of heat-sensitive compounds (carotene, etc.). The dried sample pretreated by PEF could better retain the initial product color and had a reduced color deviation after rehydration. In regards to the frying process, the application of the PEF treatment showed not only an advantage in terms of the frying time but also in terms of oil content absorbed. The oil content of PEF treated sample was lower compared to untreated ones. Moreover, the combination of the PEF pretreatment and hot air pre-drying (or vacuum pre-drying) showed a synergistic efficiency on frying time and also in terms of oil content absorbed.

Resumo: A atraente coloração da abóbora 'Rajada Seca' se deve a presença de carotenóides; compostos bioativos que estão associados ao adequado desenvolvimento e manutenção da saúde humana, bem como à redução de riscos de doenças degenerativas. As ações e funções biológicas desses compostos se devem ao sistema de duplas ligações conjugadas de sua estrutura, que os tornam altamente susceptíveis a degradações (isomerização e oxidação) durante o processamento. Dentre as técnicas de conservação de alimentos, a secagem apresenta vantagens por possibilitar a obtenção de produtos com baixos peso e volume, maior vida de prateleira a temperatura ambiente, diminuindo os custos de armazenamento e distribuição. No entanto, pode provocar alterações de cor e sabor e perda de nutrientes, decorrentes da exposição ao oxigênio e a temperaturas relativamente elevadas, principalmente quando realizada de forma convencional com ar aquecido. Assim, aplicação de tratamentos prévios a secagem, com o objetivo de melhorar a aparência, sabor, textura e retenção dos nutrientes, tem despertado o interesse de pesquisadores nos últimos anos. No presente trabalho, avaliou-se o efeito da aplicação de coberturas a base de amido no teor de carotenóides de abóbora desidratada com ar aquecido a 70 ºC, verificando o efeito do tipo de amido (nativo ou modificado de milho, mandioca e batata), da concentração dos géis formadores das coberturas (1,5; 2,0; 2,5; 3,0 e 3,5 %) e temperatura de aplicação (quente ou frio). Para análise dos carotenóides por cromatografia líquida de alta eficiência (CLAE), condições cromatográficas foram avaliadas e otimizadas. Fase móvel constituída de metanol e acetato de etila na proporção de 70:30 (v/v) com adição de 0,1 % de TEA mostrou boa separação e resolução de a-caroteno e b-caroteno e seus isômeros, em 35 minutos de corrida...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The attractive colour of the Rajada Seca variety pumpkin is due to the presence of carotenoids; bioactive compounds which are associated to adequate development and maintenance of human's health, and also to a reduction of risks of degenerative diseases. Biological actions and functions of carotenoids are due to the conjugated double bond system which makes them highly susceptible to degradation (isomerization and oxidation) during processing. Among the food preservation techniques, drying is advantageous because it results in lighter and smaller products with a longer shelf-life at room temperature, thus reducing the storage and distribution costs. However, it may cause flavor and colour alterations as well as the loss of nutrients due to exposure to oxygen and relatively high temperatures, principally when conventional drying with hot air is used. Thus, application of drying pretreatments aiming to improve the appearance, flavor, texture and nutrients retention, has awakened researchers' interest over the last years. In this study, the effect of starch edible coats on the carotenoid contents of dried pumpkin using hot air at 70 ºC was evaluated, verifying the effects of the coating gel concentration (1,5; 2,0; 2,5; 3,0 e 3,5 %) and temperature (hot and cold). For carotenoid analysis by high performance liquid chromatography (HPLC) using polymeric C30 column, chromatographic conditions were assessed and optimized. Mobile phase constituted of methanol and ethyl acetate (70:30, v/v) with 0.1 % of TEA provided good separation and resolution of the isomers of a-carotene and b-carotene in a 35 minutes run. Trans-a-carotene and trans-b-carotene content of fresh carrot and pumpkin obtained with C18 and C30 columns did not present significant differences. However, C18 column overestimated the trans-b-carotene content of processed samples due to a-carotene cis isomers coelution... (Complete abstract click electronic access below) / Orientador: Mieko Kimura / Coorientador: Maria A. Mauro / Banca: Helena Teixeira Godoy / Banca: José Antônio Gomes Vieira / Mestre

Les agrumes très consommés au niveau mondial, représente des sources de caroténoïdes tels que la β-cryptoxanthine, qui contribuent avec les flavonoïdes (hespéridine) aux effets santé de ces fruits et en particulier dans la prévention du diabète de type 2 (DT2). Le DT2 est une pathologie mondiale en croissance exponentielle. L’objectif général de ce travail est par conséquent d’étudier les propriétés nutrition-santé de concentrés de jus de clémentine, obtenus par une technologie membranaire innovante et spécifiquement enrichis en β-cryptoxanthine (βCX) et hespéridine (HES) mais également en pectines. Le devenir digestif de ces phytomicronutriments, garants de la qualité nutritionnelle des concentrés a évalué dans un premier temps en couplant le modèle de digestion in vitro aux cellules intestinales de type Caco-2. Pour une meilleure vision physiologique des mécanismes associés aux premières étapes de la digestion, des modèles de digestion, statique et dynamique, sont comparés. La bioaccessibilité et l’absorption intestinale des caroténoïdes sont fortement influencées par la teneur et structure des pectines. Dans un second temps, les activités biologiques (disglycémie, dislipidémie, inflammation) impliquées dans la prévention du DT2 sont évaluées in vivo chez le rat après administration du concentré d’agrume. L’étude a démontré qu'un aliment à base d'agrume spécifiquement enrichi en βCX et HES est efficace dans la prévention du syndrome métabolique/DT2, soulignant le rôle possible de la βCX et de sa bioconversion en rétinoïdes. Une étude in vitro complémentaire sur macrophages murins révèle des effets anti-inflammatoires synergiques des 2 phytomicronutriments. / Citrus fruits, which are widely consumed worldwide, represent sources of carotenoids such as βCX, which contribute with flavonoids (HES) to the health effects of these fruits, particularly in the prevention of type 2 diabetes (T2D). T2D is a worldwide pathology that is growing exponentially. The general objective of this work is therefore to study the nutritional and health properties of clementine juice concentrates obtained by innovative membrane technology and specifically enriched in both βCX and HES but also in pectins. The digestive behaviour of these phytomicronutrients, guarantors of the nutritional quality of the concentrates, was first assessed by coupling the in vitro digestion model with the Caco-2 intestinal cells. For a better physiological vision of the mechanisms associated with the first stages of digestion, models of static and dynamic digestion are compared. The bioavailability and intestinal absorption of carotenoids are strongly influenced by the content and structure of pectins. In a second step, the biological activities (disglycemia, dislipidemia, inflammation) involved in the prevention of T2D are evaluated in vivo in rat after administration of the citrus concentrate. The study demonstrated that a citrus food specifically enriched in βCX and HES is effective in preventing metabolic syndrome/T2D, highlighting the possible role of βCX and its retinoid bioconversion. A complementary in vitro study on murine macrophages reveals synergistic anti-inflammatory effects of the two phytomicronutrients.

<p>This thesis examines the role of dissolved inorganic nutrients in generating changes in phytoplankton community and pigment composition and if such changes can affect the production of the antioxidant astaxanthin in the ecosystem via pelagic copepods. The background of my studies is the possible relationship between eutrophication and a reproductive disturbance in Baltic populations of Atlantic salmon (M74), which is associated with astaxanthin and thiamine deficiencies and oxidative stress. In the southern Baltic Sea, changes in nutrient loads correlate with observed trends of flagellates replacing diatoms in the phytoplankton. Copepods are the main producers of astaxanthin and a major link between phytoplankton and higher trophic levels. In laboratory and field experiments in the Baltic Sea proper and the Norwegian Sea, I show that astaxanthin synthesis in copepods is fast and depends on pigment composition of the phytoplankton diet. Among single-species diets, a diatom and a green algal cyst yielded the highest astaxanthin levels in copepods, and another diatom species, a green alga and a cyanobacterium the lowest. In nutrient-generated phytoplankton blooms in mesocosms, copepods grazing on diverse communities dominated by weakly silicified diatoms produced more astaxanthin compared with copepods grazing on communities dominated by strongly silicified diatoms. This suggests that diatoms invested in defence mechanisms and escaped grazing at surplus Si. A nutrient-starved diatom culture subjected to intraspecific competition exhibited decreased pigment levels, increased thiamine levels and increased oxidative stress. </p><p>My results suggest that diatoms are beneficial for astaxanthin and thiamine production compared to other phytoplankton groups, but not under all circumstances. Copepod growth and development also responded to inorganic nutrient availability and affected total astaxanthin production per volume seawater, with highest production when the copepods grazed on diatoms. From an ecosystem perspective, increased N and P loads seem to promote high astaxanthin production, but not when diatoms disappear completely.</p>

Il verificarsi della presenza di micotossine nella granella di mais è di interesse mondiale perché la loro presenza negli alimenti è spesso associata a malattie acute e croniche nel bestiame e nell'uomo. Le micotossine sono metaboliti fungini secondari tossici per i vertebrati. Molti composti naturali e sintetici con proprietà antiossidanti sembrano avere una potenziale efficacia nella protezione contro gli effetti tossici delle micotossine. Questo lavoro ha avuto come obiettivo lo studio degli effetti degli antiossidanti naturali di mais (carotenoidi e tocoli) sulla crescita di funghi (fusarium verticillioides) e sull'accumulo di micotossine in preparati alimentari a base di mais e su alcuni sottoprodotti della lavorazione del mais. / The occurrence of mycotoxins in cereal grains is of great concern worldwide, because their presence in feeds and foods is often associated with chronic or acute mycotoxicoses in livestock and also in human. Mycotoxins are fungal secondary metabolites that are toxic to vertebrates. Several natural and synthetic compounds with antioxidant properties seem to be potentially efficient in protecting against the toxic effects of micotoxins. This work was aimed to study the effects of natural maize antioxidant (carotenoids and tocols) on fungi (fusarium verticillioides) growth and on micotoxins accumulation in maize-based food products and in maize by-products.

Poor diet precipitates significant social and economic burden, necessitating effective and economical dietary intervention strategies. Current population-level campaigns provide guidelines for living healthily and focus on the impact of lifestyle on chronic disease risk. Behavioural interventions which capitalise on individuals' existing cognitions are likely to be more effective. A programme of work is presented here which evaluates the feasibility and efficacy of an appearance-based dietary intervention approach. This project aims to improve fruit and vegetable consumption by illustrating the associated benefits to skin appearance. The impact of fruit and vegetable consumption on skin colour is assessed (Chapter 6), corroborating previous between-subjects evidence which finds that dermal yellowness (CIE b*) is positively associated with fruit and vegetable intake. This work also discovers that modest within-subject dietary change is sufficient to perceptibly alter skin colour within six weeks (Chapter 7). Perceptual preferences are examined (Chapters 5 to 9), finding that optimally healthy skin colouration is that associated with increased fruit and vegetable consumption. Two behavioural intervention trials are conducted (Chapters 6 and 9) to evaluate whether visualising the impact of fruit and vegetable consumption on skin colour motivates dietary improvement. Relative to control groups, participants receiving an appearance-based intervention (in which the above effects are illustrated and explained) reported improvements in diet, particularly when illustrations were performed upon images of one's own face. It may be valuable to disseminate such an intervention at a population level, though a number of further longitudinal studies are necessary to determine the wider effectiveness of this approach.

Το γένος Crocus ανήκει στην οικογένεια Iridaceae και περιλαμβάνει 84 είδη, τα οποία εξαπλώνονται από τη ΝΔ. Ευρώπη έως την Τουρκία και τη ΝΔ. Ασία. Στην Ελλάδα είναι γνωστά 23 αυτοφυή είδη, τα οποία περιλαμβάνουν 34 taxa, από τα οποία 17 taxa είναι ενδημικά της Ελλάδας. Στην Πελοπόννησο φύονται 12 taxa του γένους Crocus, εκ των οποίων τα 5 είναι ενδημικά της Πελοποννήσου. Το C. sativus είναι το πιο γνωστό και περισσότερο μελετημένο είδος του γένους. Στην παρούσα εργασία μελετήθηκαν πέντε ελληνικά ενδημικά taxa του γένους Crocus, τα C. biflorus ssp. melantherus, C. boryi ssp. boryi, C. goulimyi, C. laevigatus και C. niveus, ως προς τον καρυότυπό τους και τη μορφομετρία και χημική σύσταση των στύλων τους. Εξετάστηκαν ακόμα οι διαφορές στη μορφομετρία και χημική σύσταση των στύλων μεταξύ του C. sativus και των πέντε ελληνικών ενδημικών taxa καθώς και μεταξύ ίδιων taxa του γένους από διαφορετικές περιοχές. / The genus Crocus L. (Iridaceae) consists of 84 species worldwide, distributed from South-Western Europe through Central Europe to Turkey and South-Western parts of Asia. There are 23 native taxa in Greece and 17 taxa are endemic to it. In Peloponnese there exist 12 taxa and of these 5 are endemic to the region. Among these species, the cultivated C. sativus is the best known and studied. The present study examined five endemic taxa of the genus Crocus in Peloponnese: C. biflorus ssp. melantherus, C. boryi ssp. boryi, C. goulimyi, C. laevigatus and C. niveus. These taxa were examined concerning their cytology and the morphometry and chemical composition of their style. Moreover through this study was investigated the differences in morphometry and chemical composition of the styles between C. sativus and the five endemic taxa and among the same taxa from different regions.