Made available in DSpace on 2014-06-11T19:32:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-02-15Bitstream added on 2014-06-13T20:03:30Z : No. of bitstreams: 1 aiura_fs_dr_jabo.pdf: 425838 bytes, checksum: b3849e04c44d3f472d981ea17c4412ea (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo desse trabalho foi avaliar a qualidade dos filés de tilápias do Nilo alimentadas com dietas contendo óleos de soja e de linhaça e extrato de alecrim, e também verificar a ação antioxidante do extrato de alecrim em filés embalados a vácuo. No primeiro experimento, os peixes foram alimentados com dietas contendo óleo de soja, óleo de linhaça e extrato de alecrim, sendo abatidos, filetados, embalados em filme plástico e armazenados a -18ºC por 90 dias. No segundo experimento, filés de tilápia do Nilo provenientes de um cultivo em represa foram imersos em solução de extrato de alecrim nas concentrações de 0, 400, 800 e 1200 ppm, embalados sob ar atmosférico ou a vácuo e armazenados em gelo por 21 dias. Os filés de tilápias alimentadas com dietas contendo o extrato de alecrim apresentaram menores teores de lipídios (1,52%) em relação aos sem extrato (1,77%). A quantidade de ácidos graxos da série n-3 foi maior (6,22%) nos filés de tilápias alimentadas com dietas contendo óleo de linhaça do que o de soja (5,42%). Os valores de pH e BNVT para ambos os experimentos ficaram abaixo dos propostos pela legislação brasileira que estabelece limites de 6,50 e 30 mg/100g músculo, respectivamente. Todos os tratamentos apresentaram diminuição do NNP nos filés durante o armazenamento. Os filés de tilápias que receberam extrato de alecrim na dieta e na imersão apresentaram minimização da oxidação avaliada pelo TBARS. A força de cisalhamento diminuiu de 1,61 a 0,36 kgf e de 0,81 a 0,59 kgf, respectivamente para os filés do primeiro e segundo experimento. A capacidade de retenção de água diminuiu para os filés de tilápias alimentadas com dietas contendo óleo de soja (71,04%) e de linhaça (69,74%) no final do tempo de armazenamento e para os filés embalados a vácuo os valores mantiveram-se estáveis do 7º ao 21º dia... / The objective of this work was to evaluate the quality of Nile tilapia fillets fed with diets contends soy and flaxseed oil and rosemary extract, and also verify antioxidant action of rosemary extract in fillets vacuum packed. In the first experiment, the fish were fed with diets contend soybean oil, flaxseed oil and rosemary extract, being slaughtered, processed, packing in plastic film and stored at -18ºC for 90 days. In the next experiment, fillets were immersed in rosemary extract solution in the concentrations of 0, 400, 800 and 1200 ppm, packed under atmospheric or the vacuum and ice stored for 21 days. Fillets of tilapias fed with diets contend rosemary extract presented lower content of lipids (1.52%) in relation those without extract (1.77%). The amount of n-3 fatty acids was larger (6.22%) found in fillets of tilapias fed with diets contends flaxseed oil of that of soy (5.42%). The values of pH and BNVT for both the experiments were below of recommending for Brazilian legislation that establishes 6.50 e 30 mg/100g muscle, respectively. All the treatments presented reduction of the NNP in fillets during the storage. Fillets of tilapias that received rosemary extract in the diet and the immersion presented minimized of the oxidation evaluated at TBARS. The shear force decrease of 1.61 for 0.36 kgf and of 0.81 for 0.59 kgf, respectively for the fillets of first and second experiment. The liquid holding capacity decrease for fillets of tilapias fed with diet contends soybean oil (71.04%) and flaxseed oil (69.74%) at end of storage time and for fillets packed vacuum the values maintained stable of 7º to 21º day. The luminosity increased in fillets, for both the experiments, during the storage. It was verified bigger losses for cooking in the end of the storage for fillets immersed in solution of rosemary extract and packed under atmospheric air and the vacuum...(Complete abstract, acess undermentioned eletronic adress)

Orientador: Lireny Aparecida Guaraldo Gonçalves / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-16T15:19:46Z (GMT). No. of bitstreams: 1 Mascarenhas_Maria_Cristina_Chiarinelli_Nucci_M.pdf: 34073658 bytes, checksum: 2317d29ea00a70488b5f569fb05c6ce5 (MD5) Previous issue date: 2010 / Mestrado / Mestre em Tecnologia de Alimentos

Novas alternativas de produção de ácidos graxos altamente insaturados n-3 (HUFA n-3) são procuradas mediante várias abordagens experimentais na área aquícola considerando que a oferta atual de óleos marinhos é limitada. Como os ácidos graxos das séries n-3 e n-6 são metabolizados mediante os mesmos processos enzimáticos, o aporte de ácidos graxos essenciais da dieta poderia influenciar nos níveis de alongamento e desaturação em função da disponibilidade relativa destes compostos. O objetivo deste trabalho foi determinar a influência de diferentes relações 18:3n3/18:2n6 (ALA/LA - ácido linolênico/ácido linoleico) de rações exclusivamente vegetais, sobre o metabolismo de ácidos graxos de juvenis de pacu (Piaractus mesopotamicus). Inicialmente 18 unidades experimentais (caixas com 16 peixes) foram alimentadas por 34 dias (C1) com uma dieta controle (tratamento T6) contendo óleo de tilápia como único ingrediente de origem animal. Posteriormente, foram formados aleatoriamente, 6 grupos com 3 unidades experimentais cada. Em uma segunda fase, durante 72 dias, 5 grupos receberam dietas, contendo óleo de linhaça e soja em substituição ao óleo de tilápia, com relações calculadas de ALA/LA de: 2,98 (T1); 1,68 (T2); 1,03 (T3); 0,61 (T4) e 0,35 (T5) e um grupo continuou com a dieta controle (T6). Nesta segunda fase, determinaram-se parâmetros de desempenho zootécnico e metabolismo de ácidos graxos em 3 intervalos de 24 dias (C2=58 dias, C3=82 dias e C4=106 dias). Os animais apresentaram crescimento e ganho de peso sem diferenças significativas entre os grupos e com aumento progressivo da proporção de gordura corporal total. A composição de ácidos graxos da dieta influenciou de forma proporcional sobre a composição da maioria de ácidos graxos de corpo inteiro. Os coeficientes de digestibilidade aparente aumentaram conforme o grau de instauração dos ácidos graxos e sua abundância relativa na dieta. A concentração de ácidos graxos polinsaturados nos lipídios de corpo inteiro não diferiu entre a maioria de tratamentos. O teor e aparecimento do ácido graxo 20:5n3 (EPA) e a atividade da enzima Δ-5 desaturase dos grupos T1, T2 e T3 foi menor que os demais tratamentos no período C4. O aparecimento de HUFA n-3 e n-6, atividade Δ-6 desaturase total e atividade Δ-6 desaturase sobre os ácidos graxos n-3 totais dos tratamentos T1 a T5 foram maiores que no T6 (controle). Estes resultados demonstram que o pacu (Piaractus mesopotamicus) é capaz de alongar e desaturar ácidos graxos essenciais para produzir ácidos graxos altamente insaturados (ácidos graxos com no mínimo 20 C e 3 ligações duplas - HUFA). Esta atividade é diminuída pela presença, mesmo em quantidades pequenas, de HUFA na dieta. Além disso, sugerem que relações ALA/LA da dieta, iguais ou maiores que 1, provocam diminuição na taxa de produção de 20:5n3, nos níveis testados neste estudo. / New alternatives for production of highly unsaturated fatty acids n-3 (n-3 HUFA) are sought by various experimental approaches in aquaculture, considering that the current supply of marine oils is limited. Since fatty acids of the n-3 and n-6 series are metabolized by the same enzyme processes, the supply of essential fatty acids of the diet could influence the elongation and desaturation levels, depending on the relative availability of these compounds. The objective of this study was to determine the influence of different 18:3n-3/18:2n-6 ratios (ALA/LA - linolenic acid/linoleic acid) of diets containing exclusively vegetable ingredients on the metabolism of fatty acids, of pacu juveniles (Piaractus mesopotamicus). Initially, 18 experimental units (boxes with 16 animals) were fed a control diet (T6 treatment) containing tilapia oil as the sole animal ingredient for 34 days (C1). Later, 6 groups with 3 experimental units each were formed at random. In a second phase, during 72 days, five groups were fed diets containing linseed and soy oils to replace tilapia oil, with calculated ALA/LA ratios: 2.98 (T1); 1.68 (T2); 1.03 (T3); 0.61 (T4) and 0.35 (T5) and a group continued with the control diet (T6). In the second phase were determined growth performance parameters and fatty acid metabolism in three intervals of 24 days (C2 = 58 days = 82 days and C3 C4 = 106 days). The animals showed growth and weight gain with no significant differences between groups and progressive increase in the proportion of total body fat. The fatty acid composition of the diet influenced proportionally on the composition of the majority of whole body fatty acids. The apparent digestibility increased as the degree of unsaturation of fatty acids and their relative abundance in the diet. The concentration of polyunsaturated fatty acids in whole body lipids did not differ among the most treatments. The content and appearance of the fatty acid 20:5n3 (EPA) and the activity of Δ-5 desaturase enzyme of groups T1, T2 and T3 was lower than the other treatments in C4 period. The appearance of n-3 and n-6 HUFA, Δ 6-desaturase activity and the total Δ 6-desaturase activity on the total n-3 fatty acids from T1 to T5 treatments were higher than T6 (control). These results demonstrate that pacu juveniles are able to elongate and desaturate essential fatty acids to produce highly unsaturated fatty acids. This activity diminishes by the presence of even small amounts of HUFAs in the diet. Moreover, it suggests that ALA/LA ratio of diet, equal to, or greater than one, cause a decrease in the rate of production of 20:5n3, within the levels tested in this study.

Orientador: Rosiane Lopes da Cunha / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-23T01:16:34Z (GMT). No. of bitstreams: 1 Kuhn_KatiaRegina_D.pdf: 3588047 bytes, checksum: 56035122a0c4826c829bf99675b3f00c (MD5) Previous issue date: 2013 / Resumo: A encapsulação de compostos bioativos vem sendo utilizada como uma alternativa para minimizar a degradação destes ingredientes durante o processamento, armazenamento e/ou processo digestivo, permitindo o aumento da vida de prateleira dos alimentos e a liberação controlada destes compostos. Nesse sentido, o objetivo geral deste trabalho foi produzir microgéis a partir da extrusão de emulsões O/A contendo isolado protéico de soro de leite (IPS) e gelana em uma solução gelificante de cloreto de cálcio visando a encapsulação e liberação controlada de óleo e hidrolisado protéico da linhaça. Na primeira parte deste estudo, a influência das condições de homogeneização (pressão e número de passagens) no preparo de emulsões estabilizadas por IPS foi avaliada com o intuito de obter sistemas mais estáveis e com menor oxidação lipídica. Todos os sistemas foram estáveis à cremeação e um aumento da pressão de homogeneização para 800 bar e do número de passagens para até 3 vezes, diminuiu o tamanho médio de gota das emulsões. Condições extremas de homogeneização levaram à formação de agregados protéicos de alta massa molecular (>200 kDa), favorecendo o aumento na viscosidade das emulsões. Com o aumento da pressão, uma distribuição de tamanho de gotas bimodal, indicando que coalescência pode ter ocorrido, e um aumento na formação de produtos primários da oxidação foram observados. Na segunda etapa do trabalho, avaliou-se o potencial do isolado protéico da linhaça (IPL) como agente emulsificante em sistemas puros e mistos com proteínas do soro de leite preparados sob alta pressão de homogeneização. As emulsões estabilizadas por IPL ou IPSIPL mostraram-se cineticamente instáveis e o aumento da concentração de IPL e das condições de homogeneização melhoraram a estabilidade dos sistemas puros, o que foi atribuído à sua maior viscosidade. No entanto, a maior estabilidade foi obtida com a adição de IPS nas emulsões contendo menor concentração de IPL (0,14% m/v) e utilizando condições mais drásticas de homogeneização. Por último, microgéis de IPS e gelana foram produzidos a partir da gelificação iônica de emulsões visando a encapsulação de compostos bioativos da linhaça. Os microgéis foram avaliados quanto à estabilidade, resistência e liberação destes compostos bioativos através da simulação in vitro do processo digestivo. Os resultados mostraram que óleo e hidrolisado protéico da linhaça foram encapsulados e que os microgéis resistiram às condições gástricas, mas foram desintegrados no meio intestinal. Além disso, a adição de hidrolisado diminuiu o tamanho das partículas e parece ter auxiliado na encapsulação do óleo de linhaça. Sendo assim, os microgéis produzidos poderiam ser utilizados para a proteção e liberação controlada dos compostos bioativos encapsulados / Abstract: The encapsulation of bioactive compounds has been used as an alternative to minimize degradation of these ingredients during processing, storage and/or digestive process, allowing increased shelf life of foods and the controlled release of these compounds. In this way, the general purpose of this work was to produce microbeads from extrusion of the O/W emulsions containing whey protein isolate (WPI) and gellan into a gelling solution of calcium chloride aiming the encapsulation and controlled release of oil and protein hydrolysate from flaxseed. In the first part of this study, the influence of homogenization conditions (pressure and number of passes) in the preparation of emulsions stabilized by WPI was assessed in order to obtain more stable systems and decreased lipid oxidation. All the systems were stable to creaming and an increase of homogenization pressure to 80 MPa and the number of passes up to 3 times, decreased the mean droplet size of the emulsions. Extreme homogenization conditions led to the formation of high molecular weight protein aggregates (>200 kDa), favoring the increase in viscosity of the emulsions. Increasing pressure, a bimodal droplets size distribution, indicating droplets coalescence, and an increase in the formation of primary oxidation products were observed. In the second step of the work, the potential of flaxseed protein isolate (FPI) as an emulsifying agent was evaluated in pure systems and mixed with whey proteins prepared under high pressure homogenization. The emulsions stabilized by FPI or WPI-FPI were kinetically unstable and the increase of FPI concentration and homogenization conditions improved the stability of pure systems, which was attributed to its higher viscosity. However, the greatest stability was achieved with the WPI addition in the emulsions containing the lowest FPI concentration (0.14% w/v) and using more drastic homogenization conditions. Finally, WPI-gellan microgels were produced by ionic gelation of the emulsions aiming the encapsulation of bioactive compounds from flaxseed. Microgels were evaluated in relation to stability, resistance and release of these bioactive compounds by simulating in vitro digestion process. The results showed that oil and protein hydrolysate from flaxseed were encapsulated and that microbeads resisted to gastric conditions, but were disintegrated in intestinal medium. Furthermore, the hydrolysate addition decreased the particle size and seems to have contributed for the flaxseed oil encapsulation. Thus, microbeads produced could be used for protection and controlled release of the encapsulated bioactive compounds / Doutorado / Engenharia de Alimentos / Doutora em Engenharia de Alimentos

More than 50% of the world population presents conditions of lactase deficiency, in Brazil, 58 million people undergo such genetic disorder. The goal of the present work was to produce probiotic yogurt with reduced contend of lactose added flaxseed oil and to study the viability of lactic and bifid bacteria compared to the flaxseed oil and different contends of lactose. Three out of the seven developed treatments were added with 0,2; 0,5 and 0,8g of lactase enzyme per liter of milk respectively. Microbiological and physic-chemical analysis were carried out in the yogurts. The yogurts with reduced lactose presented a decrease in pH and an increase in the acidity less strong than the other yogurts during twenty-eight days of storage. The contends of lactose found in the yogurts which were added with lactase are considered low, within the patterns and regulations of the for special dietary uses legislation. The ratio found between Streptococcus salivarius ssp. Thermophilus and Lactobacillus delbrueckii ssp. bulgaricus was 2:1, which favors the decrease of postacidification. The number of viable cells of Bifidobacterium sp. and Lactobacillus acidophilus as well as the lactic bacteria stood until the end of the storage period according to the recommendations of the legislation. The fat contends were higher in yogurts added with flaxseed oil and rice flour concomitantly. Only one of the yogurts fit the legislation concerning protein contend, probably due to the substitution of powder milk by the rice flour in the yogurts. Considering the results it is possible to infer that the enzyme lactase used in the experiment efficiently hydrolyzed the lactose of the yogurts and did not compromised the viability of microorganisms of the traditional culture as the probiotic culture. / Mais de 50% da população mundial apresenta condições de deficiência de lactase, sendo que no Brasil, 58 milhões de pessoas sofrem de tal desordem genética. O objetivo deste trabalho foi o de produzir iogurte probiótico com teor reduzido de lactose e adicionado de óleo de linhaça e estudar a viabilidade das bactérias lácticas e bífidas frente ao óleo de linhaça e diferentes teores de lactose. Três dos sete tratamentos desenvolvidos foram adicionados de 0,2; 0,5 e 0,8g de enzima lactase por litro de leite respectivamente. Foram realizadas análises microbiológicas e físico-químicas nos iogurtes. Os iogurtes com reduzidos teores de lactose apresentaram queda de pH e aumento de acidez menos acentuada que os demais iogurtes em vinte e oito dias de armazenamento. Os teores de lactose encontrados nos iogurtes com adição de lactase são considerados baixos, dentro dos padrões regulamentados pela legislação de alimentos para fins especiais. A relação encontrada entre Streptococcus salivarius ssp. thermophilus e Lactobacillus delbrueckii ssp. bulgaricus foi de 2:1 favorecendo a diminuição da pós-acidificação. O número de células viáveis de Bifidobacterium sp. e Lactobacillus acidophilus assim como o de bactérias lácticas se mantiveram até o final da estocagem conforme preconizado na legislação brasileira. Os teores de gordura foram maiores para os iogurtes adicionados de óleo de linhaça e farinha de arroz concomitantemente. Apenas um dos iogurtes apresentou-se de acordo com a legislação quanto ao teor de proteínas, provavelmente pela substituição do leite em pó pela farinha de arroz na formulação dos iogurtes. Considerando os resultados obtidos pode-se inferir que a enzima lactase utilizada hidrolisou eficientemente a lactose dos iogurtes e não comprometeu a viabilidade dos microrganismos da cultura tradicional como da cultura probiótica.

Eggs enriched with omega-3 polyunsaturated fatty acids (PUFA), particularly the longer chain PUFA (LCPUFA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) can boost human consumption of these fatty acids implicated in human health. Alpha-linolenic acid (ALA) from plant seeds/oils, primarily serve as the source of omega-3 PUFA for hens, however, the scarcity of ALA-rich plants and the limited conversion of ALA to LCPUFA are challenges for egg enrichment. Two major experiments were conducted to determine potential factors regulating egg enrichment of omega-3 LCPUFA based on detailed assessment of PUFA profiles in different lipid pools of hen tissues. In experiment 1, supplementation of graded levels of hempseed products, provided ~ 0.1 to 1.3% of ALA in the diets. Experiment 2, investigated dietary supplementation of flaxseed oil (ALA-rich) and algal DHA (preformed LCPUFA), each providing similar graded levels of total omega-3 PUFA. Both ALA-containing models demonstrated a plateau in DHA enrichment of eggs at higher ALA intakes. ALA-containing diets led to high concentrations of ALA in the triacylglycerol (TAG) fraction of eggs and plasma, and the adipose tissue of flaxseed oil-fed hens. In total phospholipid (PL), particularly the phosphatidylethanolamine (PE), the levels of EPA and ALA in the yolk were linearly associated with those in the liver. In all tissues, DHA dominated the PE pool, exhibiting a plateau with a strong inverse correlation to the ratio of ALA to EPA in the liver, suggesting limited ALA availability for egg DHA enrichment. The use of algal DHA should therefore permit further accumulation of DHA in the total PL and TAG fractions of yolk. However, enrichment via preformed DHA (at 3.36% algal product) was also limited by hepatic PL resulting in more DHA and EPA being shunted to the adipose TAG, concurrent with elevated hepatic acyl-CoA synthetase (ACSL1) expression. As a function of total omega-3 PUFA intakes (regardless of source), similar levels of stearidonic acid (SDA) and particularly EPA accumulated in liver PE. Therefore, hepatic PL regulation, possibly aimed at maintaining EPA level, may potentially be limiting the amount of ALA accumulation in the same pool, hence limiting the endogenous synthesis of DHA and subsequent enrichment in eggs. / February 2017

Doctor of Philosophy / Department of Human Nutrition / Richard C. Baybutt / Weiqun George Wang / Although omega-3 fatty acids have been a hot issue in nutrition for years, there remains a paucity of research on the topic of omega-3 fatty acid and pulmonary fibrosis and the mechanism is still unclear. The purpose of this research is to investigate the preventive effects of flaxseed oil for bleomycin-induced pulmonary fibrosis in rats and to find the possible underlying mechanisms. There are two experiments demonstrated in this dissertation, one is with various doses of flaxseed oil in the diet (0, 2.5, 5, 7.5, 10, 12.5, and 15 % (w/w)), and the other is with different times of sacrificing animals after oropharyngeal bleomycin treatment (days 7 and 21). In the first study, three proteins including transforming growth factor-[beta] (TGF-[beta]), interleukin-1 (IL-1), and [alpha]-smooth muscle actin ([alpha]-SMA), commonly associated with fibrotic inflammation in the lung, were examined by Western blot and fatty acids composition of the diets and tissues were analyzed by gas chromatography (GC). Fifteen percent of flaxseed oil group significantly reduced septal and vascular thickness and fibrosis in the lung, and significant cardiac fibrosis in the heart. The amount of IL-1 and [alpha]-SMA decreased significantly as the amount of omega-3 fatty acids increased, whereas TGF-[beta] did not change significantly. The next study further reported the time-course effect and potential underlying mechanisms. Both interleukin-6 (IL-6), a protein associated with fibrotic inflammation in the lung, and renin, an enzyme related to renin-angiotensin system, were examined by Western blot. The time-dependent increase of IL-6 in response to bleomycin treatment was reversed by flaxseed oil diet. Although renin was not significantly different in the kidney, it suggested that the renin-angiotensin system may be involved locally. In addition, the profiles of fatty acids in both liver and kidney tissues as measured by lipidomics demonstrated a significant increase of omega-3: omega-6 ratio in the flaxseed oil-fed groups. Overall, these results indicated for the first time that the omega-3 fatty acids rich in flaxseed oil inhibited the formation of pulmonary fibrosis in a dose-dependent manner - however the moderate dose of flaxseed oil was most effective - via anti-inflammatory mechanisms, which appears associated with the modulated fatty acid composition in the tissues.

Orientadores: Miriam Dupas Hubinger, Renata Valeriano Tonon / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-18T16:18:35Z (GMT). No. of bitstreams: 1 Carneiro_HelenaCristinaFerrer_M.pdf: 21138565 bytes, checksum: e9e86ca2fb3c8dd5e10ab4589e33c15e (MD5) Previous issue date: 2011 / Resumo: O óleo de linhaça é um óleo rico em ácidos graxos poliinsaturados bastante susceptível à oxidação lipídica, que pode ocorrer durante o processamento, manipulação e estocagem, provocando o aparecimento de aromas desagradáveis e a redução de sua vida de prateleira. Nesse contexto, a microencapsulação por spray drying representa uma alternativa no sentido de proteger o óleo contra a oxidação, diminuir as reações do mesmo com o ambiente externo e facilitar seu manuseio. A maltodextrina é um amido hidrolisado muito utilizado como material de parede e possui vantagens como baixo custo, boa disponibilidade e eficiência na proteção contra oxidação; porém é deficiente em relação à capacidade emulsificante. Este trabalho teve como objetivo avaliar o efeito da combinação de maltodextrina com diferentes materiais de parede (goma arábica, concentrado protéico de soro e dois tipos de amidos modificados), em diferentes concentrações, na microencapsulação do óleo de linhaça por spray drying, visando-se maximizar a eficiência de encapsulação e minimizar a oxidação lipídica. As propriedades da emulsão a partir da qual as partículas foram produzidas influenciaram o processo de microencapsulação por spray drying. O aumento da concentração de maltodextrina levou a uma diminuição da viscosidade das emulsões. Em relação às propriedades das partículas, todos os pós apresentaram baixo conteúdo de umidade e atividade de água e uma distribuição de tamanho com comportamento bimodal. As combinações de HiCap/maltodextrina e goma arábica/maltodextrina apresentaram maiores eficiências de encapsulação na proporção de 75/25, sendo que a primeira apresentou a maior eficiência entre todas as combinações estudadas. Dessa forma, a proporção 75/25 (material de parede/maltodextrina) foi selecionada e as partículas produzidas nessas condições, assim como o óleo não encapsulado foram submetidos a um estudo de estabilidade sendo que a combinação de concentrado protéico de soro/maltodextrina foi considerada a melhor na proteção do óleo de linhaça contra oxidação / Abstract: Flaxseed oil is rich in polyunsaturated fatty acids highly susceptible to lipid oxidation, which can occur during processing, handling and storage, causing the appearance of unpleasant aromas and reducing its shelf life. In this context, the microencapsulation by spray drying is an alternative way to protect the oil against oxidation, reducing the reactions of this product with the external environment and to facilitate its handling. Maltodextrin is a hydrolyzed starch that has been used as wall material. It has advantages such as low cost, good availability and good efficiency in protection against oxidation, but it lacks in relation to emulsifying capacity. This study aimed to evaluate the effect of combinations of maltodextrin with different wall materials (gum arabic, whey protein concentrate and two types of modified starch) at different concentrations, in the microencapsulation of flaxseed oil by spray drying, in order to maximize the encapsulation efficiency and minimize lipid oxidation. Emulsion properties from which the particles were produced influenced the microencapsulation process by spray drying. The increase in maltodextrin concentration led to a decrease in emulsion viscosity. About particles properties, all powders showed low moisture content and low water activity. Particles size distribution had a bimodal behavior. The HiCap/maltodextrin and gum arabic/maltodextrin combinations had higher encapsulation efficiencies in the 75/25 proportion and the first one was the most efficient of all. Thus, this proportion was selected and the particles produced under these conditions, as well as the oil not encapsulated, were subjected to a stability study where the whey protein concentrate/maltodextrin combination was considered the best in protection of the active material against oxidation / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos

The objectives of our study were to determine the potential of 1H MRS in detecting (1) early colonic inflammation, (2) effects of various fatty acids on normal colon and (3) their effects on IBD. Sprague dawley rat fed with 2% carrageenan was used as a model of IBD. Flaxseed oil served as ω-3, corn oil as ω-6 and beef tallow as saturated fatty acid sources. Control group animals were fed 5% corn oil, whereas, those in high-fat diet groups received an additional 7% of the respective fatty acids. After 2 weeks, 1H MRS and histology were conducted on excised colonic mucosa. Statistical classification strategy (SCS) used for analyzing 1H MRS data achieved an accuracy of 82 % in stage 1, 90-100% in stage 2 and 96-100% in stage 3. This implies that 1H MRS is a sensitive tool to diagnose early IBD and the effects of dietary fat on IBD.

The objectives of our study were to determine the potential of 1H MRS in detecting (1) early colonic inflammation, (2) effects of various fatty acids on normal colon and (3) their effects on IBD. Sprague dawley rat fed with 2% carrageenan was used as a model of IBD. Flaxseed oil served as ω-3, corn oil as ω-6 and beef tallow as saturated fatty acid sources. Control group animals were fed 5% corn oil, whereas, those in high-fat diet groups received an additional 7% of the respective fatty acids. After 2 weeks, 1H MRS and histology were conducted on excised colonic mucosa. Statistical classification strategy (SCS) used for analyzing 1H MRS data achieved an accuracy of 82 % in stage 1, 90-100% in stage 2 and 96-100% in stage 3. This implies that 1H MRS is a sensitive tool to diagnose early IBD and the effects of dietary fat on IBD.