Consommateurs, chercheurs et industriels cherchent de plus en plus à associer à la valeur nutritionnelle des aliments, un effet bénéfique pour la santé. Les aliments caractérisés par des pouvoirs antioxydants élevés semblent correspondre à cette demande. En effet, plusieurs travaux mentionnent les bénéfices santé de ces aliments. Pour répondre à cette demande les industriels mettent en avant ce critère. La fonctionnalité alimentaire, aux bénéfices prometteurs pour la santé publique, reste un concept néanmoins complexe dans la pratique. Ce travail met l’accent sur le fait que les propriétés fonctionnelles d’un aliment ne sont pas directement liées à la composition en ingrédients. L’évaluation du pouvoir antioxydant d'un aliment est dans la plupart des cas réalisée à partir des valeurs des différents ingrédients avant formulation et mise en œuvre des procédés. Pourtant, plusieurs phénomènes sont susceptibles de modifier le pouvoir antioxydant lors de la durée de vie d'un produit alimentaire. D’un point de vue industriel, il est nécessaire de développer une méthode de prédiction de cette activité. Les objectifs de ce travail étaient d’adapter une méthode reproductible et facile à réaliser de quantification du pouvoir antioxydant sur des aliments complexes et de comparer cet index d'un ensemble de produits contenant une large gamme de matières premières. Enfin, a été discuté l’intérêt que représente, dans le domaine des propriétés anti oxydantes, la quantification de l’index créé. Au moment où les industriels vont être amenés à proposer des allégations liées à l’effet bénéfique de l’aliment choisi parmi un échantillon de plus en plus ample / Consumers, researchers and industrialists try more and more to associate with the nutritional value of food, a beneficial effect for the health. Food characterized by high antioxidant powers seems to correspond to this demand. From an industrial point of view, it is necessary to develop methods of predicting this antioxidant capacity. The objectives of this work were to adapt a method reproducible and easy to realize of quantification of the antioxidant power on complex food and to compare this index of a set of products containing a wide range of raw materials. Until now, it has been considered that the use of raw materials characterized by a high antioxidant capacity also leads to a preparation with a high antioxidant activity. We evaluated many of the factors affecting the antioxidant activity of convenience foods (phenol content, effects of formulation, culinary reheating, and preservation) and to provide data on convenience foods consumed by the French population. The total antioxidant capacity of the ethanolic extracts was evaluated by the method of the equivalent Trolox (TEAC) using the radical cation ABTS•+. The concentration of the total phenolic compounds of the same extracts was determined by the Folin-Ciocalteu method. The results show that the food matrix is an important factor for the modulation of activities of antioxidants. A standardised testing protocol for evaluating antioxidative effects is necessary. Then, we discussed the interest of an index, as the industrialists are going to be brought to claim to the beneficial effect of the food chosen among a more and more ample sample

Made available in DSpace on 2014-12-17T15:01:58Z (GMT). No. of bitstreams: 1 RosaneLAS_TESE.pdf: 1312520 bytes, checksum: 82a532d76af3f2c9d016ea88510460fc (MD5) Previous issue date: 2014-08-01 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The Brazilian caatinga is characterized by low annual rainfall and arid soils. Several cactaceae, either native or adapted species, grow in this semi-arid region, including the prickly pear (Opuntia f?cus indica) and facheiro ((Philosocereus pachycladus Ritter) which produce underexploited edible fruits. In addition to these species, the algaroba is a leguminous with little studied technological applications and bioactive potential so far. Therefore, this research aims to investigate the physicochemical, bioactive and functional attributes of the prickly pear and facheiro fruit pulps and the algaroba flour. Specifically, this study approaches the physicochemical characterization, total phenolic compounds (TPC) and the betalain identification and quantification by HPLC-DAD-ESI-MS. It is also investigated the DPPH antioxidant capacity and the antienzymatic activities against alpha-amylase and alphaglucosidase of water and ethanolic extracts of these food material. In order to address their potential to be used as food ingredients, juice blends prepared with mixtures of caj? and prickly pear, biofilms with facheiro and cereal bars with algaroba flour were elaborated and analyzed. The prickly pear fruits presented low acidity and high sugar content when compared to facheiro. The Philosocereus pachycladus Ritter fruits had higher protein and ash content, but the algaroba flour was the species with higher protein and sugar content among all. The algaroba flour also presented outstanding food fiber content, which reveals its potentiality to be used as a natural intestinal regulator. The TPC of water and ethanol extracts ranged from 3.87 to 16.21 mg GAE/100g for algaroba flour, 79.24 to 110.20 GAE/ 100g for prickly pear and 412.23 to 539.14 mg GAE/100g for facheiro. The 70% (w/v) ethanol extract reached the highest DPPH antioxidant activity, which was linearly correlated to its high TPC content. In regard to the enzymatic inhibitory activities, the best performance was observed for the prickly pear extracts which presented a moderate inhibition for both investigated enzymes, but interestingly, no alpha-glucosidase inhibition was observed for facheiro extracts. This work shows, for the first time in the literature, the functional attributes of facheiro fruits, as well as the presence of betacianins and isobetanin in the pulp of this exotic fruit. When it comes to the food products developed here, the sensory attributes that better described the juice blend caj?-prickly pear were sweetness, acidity, color yellow-orange, body, turbidity and caj? flavor. The discriminative test applied for cereal bars produced with and without algaroba revealed that the texture was the only sensory attribute that differed (p<0.05) between these two samples. It was also observed that the addition of facheiro extracts did not influence the visual characteristics of the biofilms. Overall, this work unveils the physicochemical and bioactive attributes of these commercial and technologically underexploited species widely found in the Brazilian caatinga and presents alternatives for their rational use / O semi?rido brasileiro configura-se por condi??es clim?ticas e de solo desfavor?veis e vegeta??o resistente a longos per?odos de estiagem. As esp?cies de cact?ceas nativas ou adaptadas ? regi?o, como o figo da ?ndia (Opuntia f?cus indica) e facheiro (Philosocereus pachycladus Ritter), t?m frutos comest?veis pouco conhecidas. Al?m destas esp?cies, a leguminosa algaroba ? uma mat?ria-prima com caracter?sticas ainda pouco investigadas do ponto de vista tecnol?gico e teor de subst?ncias bioativas. Desta forma, este trabalho objetivou realizar a caracteriza??o f?sico-qu?mica, bioativa e funcional da polpa das cact?ceas figo da ?ndia e facheiro e da farinha de algaroba. O estudo incluiu a determina??o do teor de compostos fen?licos, identifica??o e quantifica??o das betala?nas por HPLC-DADESI- MS, al?m da investiga??o da atividade antioxidante e inibi??o das enzimas alfa-amilase e alfa-glicosidase, utilizando extratos aquosos e etan?licos obtidos a partir das esp?cies avaliadas. Como estrat?gias de aproveitamento, elaborou-se suco misto do figo da ?ndia, biofilmes a partir do facheiro e barra de cereal a partir da farinha de algaroba. A caracteriza??o do figo da ?ndia revelou baixa acidez e elevada do?ura, quando comparada ao facheiro. O fruto do Philosocereus pachycladus Ritter, por sua vez, apresentou maior conte?do prot?ico e de cinzas. No entanto, a maior fra??o proteica e a??cares est? contida na farinha de algaroba. O conte?do de fibra alimentar total (FAT) revelou a potencialidade da farinha de Prosopis juliflora para atuar como reguladora da fun??o intestinal. O teor de fen?lico total para extratos aquosos e etan?licos variaram de 3,87 a 16,21 mg GAE/100g para a farinha de algaroba, 79,24 a 110,20 mg GAE/100g para o figo da ?ndia e facheiro 412,23 a 539,14 mg GAE/100g. O extrato etan?lico a 70% do figo da ?ndia apresentou elevada atividade antioxidante, por?m o meior percentual fen?lico foi observado no facheiro. Em rela??o ? inibi??o enzim?tica, o melhor desempenho foi observado em extratos do figo da ?ndia, os quais exibiram inibi??o moderada para as duas enzimas estudadas, enquanto que n?o foi identificada inibi??o glicol?tica para o extrato aquoso de facheiro. O presente trabalho mostra, pela primeira vez na literatura, resultados in?ditos sobre a funcionalidade do facheiro, que incluem a presen?a das betala?nas betacianina e isobetanina na polpa desse fruto. No que diz respeito aos produtos desenvolvidos, as caracter?sticas sensoriais que melhor descreveram o suco misto de figo da ?ndia e caj? foram do?ura, acidez, cor amarela-alaranjada, corpo, turbidez e aroma de caj?. A an?lise discriminativa da barrinha de cereal elaborada com e sem farinha de algaroba mostrou que apenas o atributo textura foi diferente estatisticamente (p < 0,05) para as formula??es testadas. Os resultados tamb?m indicam que a adi??o do extrato do facheiro n?o modificou visualmente as caracter?sticas dos biofilmes. De maneira geral, o presente estudo revela as caracter?sticas f?sico-qu?micas e bioativas desses vegetais abundantemente encontrados na caatinga brasileira, mas ainda pouco explorados sob pontos de vista tecnol?gico e comercial, bem como sugere alternativas de aproveitamento para tais esp?cies