Orientador: Roberto Herminio Moretti / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T02:30:32Z (GMT). No. of bitstreams: 1 Freitas_DanielaDeGrandiCastro_D.pdf: 989026 bytes, checksum: c9f4c5d7a467d08716626299b2917043 (MD5) Previous issue date: 2005 / Resumo: Nutrientes são necessários para o desenvolvimento e crescimento dos indivíduos. No entanto, uma nutrição preventiva pode proteger, minimizar ou mesmo protelar riscos a saúde que podem ser causados por pré-disposições genéticas, maus hábitos alimentares e até agressões do meio ambiente. As evidências epidemiológicas estão continuamente providenciando recomendações para que as pessoas consumam mais frutas e vegetais como medida preventiva para reduzir o risco de diversas doenças degenerativas. É notável o aumento do consumo de alimentos saudáveis devido à crescente preocupação com a melhoria da qualidade de vida, porém, o ritmo da vida moderna exige alimentos práticos. Dentro deste contexto, do crescimento visível do desenvolvimento de alimentos para fins especiais, da necessidade de combinar saúde e praticidade, e de reunir alguns ingredientes que vem recebendo grande atenção para a aplicação nestes alimentos funcionais, é que se elaborou o estudo de desenvolvimento e estabilidade de barra de cereais a base de proteína de soja, gérmen de trigo e aveia, incluindo como ingrediente a lecitina de soja, e suplementada com vitaminas C e E. Este trabalho teve por objetivo o desenvolvimento da formulação da barra de cereais e a avaliação das características físico-químicas, vitamínicas, enzimáticas, sensoriais e de textura durante o seu armazenamento. Um estudo preliminar de inativação enzimática no gérmen de trigo foi realizado devido à susceptibilidade a rancidez, fator adverso de qualidade de cereais desidratados. Amostras de aveia laminada integral e gérmen (produto natural inalterado da moagem do trigo) foram caracterizadas e a atividade de lipase e peroxidase medidas. Foi utilizado um delineamento fatorial completo para estudar os efeitos dos fatores ¿temperatura¿ e ¿tempo¿ na inativação das enzimas e para a determinação das condições ótimas de redução de atividade no gérmen de trigo. Foram determinadas como condições ótimas tratamentos térmicos à temperatura na faixa de 180 a 190°C, com duração de 4,8 a 8,0 minutos e obtidas reduções significativas (p£0,5) na atividade residual da lipase e peroxidase. O gérmen de trigo teve seu teor de umidade ajustado para 28% e a torração foi realizada em estufa a 180°C por 8,0 minutos, para que pudesse ser utilizado como ingrediente da barra de cereais. Desenvolveu-se então uma formulação de barra de cereais funcional sabor banana com alto teor protéico, à base de proteína de soja, gérmen de trigo e aveia, e enriquecida de vitaminas C (ácido ascórbico) e E (acetato de a-tocoferol 50%). A barra de cereais e seus principais ingredientes foram submetidos a análises físico-químicas para caracterização e três formulações variando o teor de ácido ascórbico foram avaliadas quanto à aceitação sensorial e intensidade ideal de doçura e acidez. A proteína de soja texturizada utilizada apresentou elevados teores dos oligossacarídeos rafinose e estaquiose (1,92 g/100g e 4,66 g/100g) e de isoflavonas totais (283,49 mg/100g) se comparados ao grão, farinha integral e isolado protéico. A formulação final da barra de cereais apresentou 15,31% de proteína e elevado teor de vitamina E (118,0 mg/100g) e minerais como fósforo (P), cálcio (Ca), cobre (Cu), ferro (Fe), manganês (Mn) e zinco (Zn). A formulação adicionada de 1,1g/100g de ácido ascórbico obteve maior aceitação sensorial diferindo significativamente (p£0,5) das demais amostras. Esta formulação, preferida pela equipe sensorial, foi então submetida ao estudo de estabilidade durante o seu armazenamento. Foram utilizados como embalagens três filmes (A: PET/PEBD; B: PETmet/PEBD; C: PET/PEBD/AL/PEBD) com diferentes propriedades de barreira. As barras de cereais foram armazenadas em condições de temperatura e umidade relativa ambiente por um período de 180 dias. Durante o armazenamento, estudou-se a estabilidade das vitaminas C, vitamina E, e a atividade de lipase e peroxidase. No período de 180 dias, as barras de cereais acondicionadas nos três materiais testados apresentaram uma retenção de vitamina C menor que 50%. No entanto, a embalagem com folha de alumínio proporcionou menor velocidade de reação e maior tempo de meia vida de 146 dias. Os teores de vitamina E (acetato de a-tocoferol) nas barras de cereais apresentaram pequenas variações durante o armazenamento. Houve um aumento significativo (p£0,5) da atividade de peroxidase durante o período de 90 dias de estocagem nas embalagens testadas, provavelmente devido à regeneração dessa enzima, enquanto que a atividade de lipase não demonstrou aumento significativo durante os 180 dias de estocagem. Foram acompanhados também a umidade, atividade de água, pH, acidez total e medidas físicas associadas à textura como resistência ao corte, dureza e coesividade. A avaliação sensorial foi realizada através de teste de aceitação e intenção de compra durante o armazenamento. As barras de cereais formuladas com os ingredientes alternativos apresentaram variações na atividade de água (Aa), umidade e acidez total durante o armazenamento. A umidade das barras de cereais tendeu a um aumento, o que acarretou influência significativa (p£0,5) nas características de textura de resistência ao corte e dureza. As barras de cereais formuladas com proteína texturizada de soja, gérmen de trigo e aveia obtiveram boa aceitação sensorial perante consumidores nos atributos de sabor e aspectos visuais, porém, a aceitação tendeu a um declínio ao longo do tempo, associado à diminuição da intenção de compra do produto. O efeito das diferentes propriedades de barreira dos filmes de embalagens testados foi significativo (p£0,5) na estabilidade das barras de cereais ao longo do período de estocagem / Abstract: Nutrients are required for development and growth of individuals. However a preventative nutrition could be protected, minimized or delayed by way from health risks arising from genetic aggressions, the environment and also eating habits. Epidemiological evidence is constantly providing recommendations that people should consume more fruits and vegetables as a preventative measure to reduce the risk of various degenerative diseases. The increase in consumption of health foods is notable, due to the increasing concern with the improvement of life quality, although the pace of modern life demands practical foods. Within this context of a visible growth in the development of foods for special ends, of the need to combine health and practicality and aiming to bring together some ingredients which have received special attention for application in such functional foods, a study of the development and stabilization of a cereal bar based on soy protein, wheat germ and oat was elaborated, with the addition of soy lecithin and supplemented with vitamins C and E. Thus the objective of this study was the development and formulation of a cereal bar and an evaluation of its physicochemical, vitamin, enzymatic, sensory and texture characteristics during storage. A preliminary study of the enzymatic inactivation of wheat germ was carried out due to its susceptibility to rancidity, a process reducing the quality of dehydrated cereals. Samples of whole rolled oats and wheat germ (natural, unaltered product from wheat milling) were characterized and their lipase and peroxidase activities determined. A complete factorial design was used to study the effects of time and temperature in the inactivation of the enzymes and to determine the optimal conditions to reduce their activity in wheat germ. The optimal conditions were shown to be a temperature in the range from 180 to 190°C for between 4.8 and 8.0 minutes, obtaining significant (p£0,5) reductions in the residual activities of lipase and peroxidase. The moisture content of the wheat germ was adjusted to 28%, which was then roasted at 180°C for 8.0 minutes such that it could be used as an ingredient in cereal bars. A functional, banana flavored cereal bar was formulated with high protein content, based on soy protein, wheat germ and oat, and enriched with vitamins C (ascorbic acid) and E (50% a-tocopherol). The cereal bar and its main ingredients were characterized by way of physicochemical analyses, and three formulations, varying in their ascorbic acid contents, prepared and submitted to a sensory acceptance test and ideal test for the intensity of sweetness and acidity. The textured soy protein used showed high contents of the oligosaccharides raffinose and stachyose (1.92 g/100g and 4.66 g/100g) and of total isoflavones (283.49 mg/100g) as compared to the bean, whole flour and protein isolate. The final formulation of the cereal bar showed 15.31% protein and high contents of vitamin E (118.0 mg/100g) and minerals such as phosphorus (P), calcium (Ca), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn). The formulation with 1.1 g/100g of ascorbic acid was the most accepted sample, differing significantly (p£0,5) from the other samples. This most accepted formulation was submitted to an evaluation during storage. Three films were used for packaging: (A: PET/PEBD; B: PETmet/PEBD; C: PET/PEBD/AL/PEBD), each with distinctive barrier properties. The cereal bars were studied under environmental conditions of temperature and relative humidity for 180 days. Vitamins C and E stabilities and the activities of lipase and peroxidase were determined during storage. The cereal bars packaged in the three materials tested showed vitamin C retention below 50% after 180 days storage. However the packaging including aluminum foil provided a lower reaction velocity and longer half life of 146 days. The vitamin E (a-tocopherol acetate) contents of the cereal bars presented slight variations during storage. There was a significant increase in peroxidase activity during the first 90 days of storage in all the types of packaging tested, probably due to regeneration, whilst lipase activity showed no significant increase during the 180 days of storage. The moisture content, water activity, pH and total acidity were also determined during storage as well as the textural measurements of cutting resistance, hardness and cohesiveness. The acceptance and intention to buy tests were used for the sensory evaluation during storage. The cereal bars formulated with alternative ingredients showed variations in water activity (Aw), moisture content and total acidity during storage. The moisture contents of the cereal bars tended to increase during storage, with a significant (p£0,5) influence on the textural characteristics of cutting resistance and hardness The cereal bars formulated with textured soy protein, wheat germ and oats were well accepted by the consumers in the sensory evaluation (flavor and visual aspect), although the acceptance tended to decline during storage, associated with a decrease in intent to buy. The effect of the different barrier properties of the packaging films tested was significant (p£0,5) in the stability of the cereal bars during storage / Doutorado / Tecnologia de Alimentos / Doutor em Tecnologia de Alimentos

Les protéines extraites des végétaux sont des matériaux relativement peu coûteux, non toxiques, biocompatibles et biodégradables. Elles représentent une bonne alternative aux protéines d’origine animale et aux polymères dérivés du pétrole. Dans le cadre de cette étude, les protéines extraites de graines de soja et de tournesol ont été utilisées en tant que matériaux enrobants pour la microencapsulation de la matière active hydrophobe (α-tocophérol) ou hydrophile (acide ascorbique) par le procédé d’atomisation. Les protéines de soja sont largement utilisées dans les applications alimentaires et non-alimentaires, notamment en microencapsulation. Elles sont donc étudiées dans ce travail comme matériau enrobant de référence. Les protéines de tournesol n’ont quant à elles pas d’application industrielle concrète, si ce n’est sous la forme de tourteaux dans l’alimentation animale. C’est pourquoi il nous semble pertinent de trouver des nouvelles voies de valorisation pour ce coproduit d’origine agricole. Plusieurs modifications des protéines, telles que l’hydrolyse enzymatique, l’acylation, la réticulation enzymatique et la cationisation ont été étudiées dans le but d’améliorer les propriétés encapsulantes du matériau enrobant. Dans le contexte de la chimie verte, toutes les modifications ont été effectuées sans utilisation de solvants organiques ni de catalyseurs chimiques. L’influence des modifications chimiques et enzymatiques des protéines, et des paramètres du procédé (pression d’homogénéisation, ratio matériau enrobant/matière active et concentration en protéines) sur les différentes caractéristiques des préparations liquides et des microparticules (viscosité, taille des gouttelettes dans le cas des émulsions, morphologie et taille des microparticules), ainsi que sur les paramètres liés au procédé d’atomisation (rendement et efficacité de microencapsulation) a été particulièrement étudiée au cours de ce travail. Les résultats obtenus confirment que l’extrait protéique de tournesol est tout à fait pertinent comme matériau enrobant et permet d’obtenir des efficacités de microencapsulation significativement plus élevées par rapport à celles obtenues avec l’extrait protéique de soja. / Proteins extracted from vegetables are relatively low-cost, non-toxic, biocompatible and biodegradable raw materials. They represent a good alternative to animal-based proteins and petroleum-extracted polymers. In this study, proteins derived from soybean and sunflower seeds were used as wall materials for microencapsulation of hydrophobic (-tocopherol) or hydrophilic (ascorbic acid) active material by spray-drying technique. Soybean proteins are widely used in food and non-food applications, especially in microencapsulation. They were studied in this work as wall material of reference. Sunflower proteins are not actually used in industrial application, but only in the form of oil-cake for animal feeding. That’s why new ways of valorization of this agricultural by-product should be investigated. Several proteins’ modifications such as enzymatic hydrolysis, acylation, cross-linking and cationization were studied in order to improve encapsulating properties of wall material. In the context of green chemistry, all the modifications and preparations were performed without use of organic solvents and chemical catalysts. The effect of protein chemical and enzymatic modifications, and process parameters (homogenization pressure, wall/core ratio and protein concentration) on different characteristics of liquid preparations and microparticles (viscosity, emulsion droplet size, microparticle size and morphology) and on parameters related to the spray-drying process (yield and efficiency of microencapsulation) was particularly investigated in this study. The obtained results confirmed that sunflower proteins are quite suitable as encapsulating agent and provide the microencapsulation efficiencies significantly higher compared to those obtained with soy proteins.

Les protéines isolées végétales sont une source renouvelable de matière première, disponible en grande quantité. Malgré des propriétés mécaniques faibles par rapport aux polymères traditionnels, elles possèdent d’autres spécificités intéressantes comme leur biodégradabilité, leur filmabilité et leur absence de toxicité. Cette étude s’est focalisée sur l’influence du procédé d’élaboration, la compatibilité et l’ajout de nanocharges sur les propriétés de mélanges poly(butylène succinate - co - adipate)/protéines de soja isolées plastifiées (PBSA/PISP). Dans un premier temps, les protéines de soja sont plastifiées et mélangées au poly(butylène succinate - co - adipate), dans des proportions différentes et extrudées simultanément en une étape d’extrusion. Ensuite, l’effet de l’ajout du poly(2-éthyl-oxazoline) comme compatibilisant a été étudié. L’addition de ce compatibilisant permet d’améliorer l’interface et les propriétés thermiques. En outre, l’addition de nanotubes d’halloysite permet d’améliorer certaines propriétés mécaniques et thermiques. Enfin dans le cas de films préparés avec une composition PBSA/PISP égale (50/50), le compatibilisant améliore les propriétés optiques, tandis que l’ajout des nanotubes d’halloysite améliore les propriétés de barrière à la vapeur d’eau et retarde la dégradation du film enfoui dans un sol. L’ensemble des résultats donne de premières indications sur l’usage potentiel de ces films dans le domaine de l’emballage et éventuellement dans le biomédical. / Vegetable isolated proteins are a renewable source of raw material, available in the large quantities. In spite of weak mechanical properties compared with the traditional polymers, they possess other important characteristics such as biodegradability, filmability and they are non-toxic. This study investigated the effect of processing type, compatibilization and addition of nanofillers on the properties of poly(butylene succinate-co-adipate)/plasticized isolated soy protein blends (PBSA/PISP). Initially, plasticizing and blending of soy protein with poly (butylene succinate-co-adipate) at various composition were carried out simultaneously in a single step extrusion. Then, the effect of adding poly(2-ethyl oxazoline) as compatibilizer has been studied. Addition of compatibilizer improves the interface and thermal properties of the blends. Besides, addition of halloysite nanotubes improves some mechanical and thermal properties. Finally, in the case of blend films prepared with equal PBSA/PISP composition (50/50), the compatibilizer increases the optical properties whereas addition of halloysite nanotubes improves the water vapour barrier properties and delay the degradation of blends as tested by soil buriel test. The overall results gives preliminary insights into potential usage of these films in packaging and possibly in biomedical sector.