The impact of the source of n-3 fatty acids on cardiovascular disease has not been fully investigated. This study was carried out to investigate cardiovascular benefits of diets with a low ratio (2:1) of n-6:n-3 fatty acids from different sources, either fish or flaxseed oil, in C57BL/6 mice. Twenty-one mice were divided into 3 groups (n=7) and fed an atherogenic diet supplemented with either a fish or flaxseed oil-based ‘designer oil’ with low n-6:n-3 fatty acid ratio (treated groups) or safflower oil-based formulation with a high ratio (control group) for 16 weeks. Plasma cholesterol levels declined significantly in both treated groups, by greater than 30%, compared to those in control. The ratio of n-6:n-3 fatty acids in liver was significantly lower in fish and flax groups as compared to control. Our data suggest that lowering dietary ratio of n-6:n-3 fatty acids may significantly reduce cardiovascular risks regardless of the source of n-3 fatty acids. / October 2008

The impact of the source of n-3 fatty acids on cardiovascular disease has not been fully investigated. This study was carried out to investigate cardiovascular benefits of diets with a low ratio (2:1) of n-6:n-3 fatty acids from different sources, either fish or flaxseed oil, in C57BL/6 mice. Twenty-one mice were divided into 3 groups (n=7) and fed an atherogenic diet supplemented with either a fish or flaxseed oil-based ‘designer oil’ with low n-6:n-3 fatty acid ratio (treated groups) or safflower oil-based formulation with a high ratio (control group) for 16 weeks. Plasma cholesterol levels declined significantly in both treated groups, by greater than 30%, compared to those in control. The ratio of n-6:n-3 fatty acids in liver was significantly lower in fish and flax groups as compared to control. Our data suggest that lowering dietary ratio of n-6:n-3 fatty acids may significantly reduce cardiovascular risks regardless of the source of n-3 fatty acids.

The impact of the source of n-3 fatty acids on cardiovascular disease has not been fully investigated. This study was carried out to investigate cardiovascular benefits of diets with a low ratio (2:1) of n-6:n-3 fatty acids from different sources, either fish or flaxseed oil, in C57BL/6 mice. Twenty-one mice were divided into 3 groups (n=7) and fed an atherogenic diet supplemented with either a fish or flaxseed oil-based ‘designer oil’ with low n-6:n-3 fatty acid ratio (treated groups) or safflower oil-based formulation with a high ratio (control group) for 16 weeks. Plasma cholesterol levels declined significantly in both treated groups, by greater than 30%, compared to those in control. The ratio of n-6:n-3 fatty acids in liver was significantly lower in fish and flax groups as compared to control. Our data suggest that lowering dietary ratio of n-6:n-3 fatty acids may significantly reduce cardiovascular risks regardless of the source of n-3 fatty acids.

The overall goal of this research was to develop a plant protein-based microcapsule capable of carrying, protecting and delivering flaxseed oil within the food and gastrointestinal environment. Specifically, the research aimed to: a) screen a variety of plant proteins and pre-treatment conditions based on their emulsifying properties for use as a wall material; b) develop and optimize encapsulation protocols for entrapping flaxseed oil; and c) study the oxidative stability and delivery of entrapped oils from capsules under different environmental and simulated gastrointestinal conditions. In Chapter 3 and 4, the emulsifying and physicochemical properties of legume and oilseed protein isolates, respectively produced from isoelectric precipitation and salt extraction were investigated. Findings in Chapter 3 indicated that both the legume source and method of production showed significant effects on the emulsifying and physicochemical properties of chickpea (ChPI), faba bean (FbPI), lentil (LPI), pea (PPI), and soy (SPI) protein isolates. The emulsion capacity (EC) values ranged between 476-542 g oil/g protein with LPI showing the highest capacity. Isoelectric-precipitated ChPI and LPI displayed higher emulsion activity index (EAI) (~46.2 m2/g), (emulsion stability index) ESI (~84.9 min) and (creaming stability) CS (98.6%), which were comparable to those of SPI. In Chapter 4, findings indicated that both protein source and method of production had significant effects on the physicochemical and emulsifying properties of canola (CaPI) and flaxseed protein isolates (FlPI). CaPI showed significantly higher EC (~515.6 g oil/g protein) than FlPI (~498.9 g oil/g protein). EAI for FlPI was found to be higher (~40.1 m2/g) than CaPI (~25.1 m2/g) however, ESI values of CaPI and FlPI were similar. Creaming stability of emulsions stabilized by CaPI and FlPI ranged between 86.1 and 96.6%. CaPI and FlPI were shown to have emulsion forming properties; however their stability was low. In Chapter 5, ChPI and LPI-stabilized emulsions were optimized based on pH, protein concentration and oil content for their ability to form and stabilize oil-in-water emulsions using response surface methodology. Droplet charge was shown to be only affected by pH, while droplet size and creaming index were affected by protein concentration, oil content and pH. Optimum conditions for minimal creaming (no serum separation after 24 h), small droplet size (<2 μm), and high net droplet charge (absolute zeta potential (ZP) value >40 mV) were identified as: 4.1% protein, 40.0% oil, and pH 3.0 or 8.0, regardless of the plant protein used for emulsion preparation. Flaxseed oil was microencapsulated by freeze (Chapter 6) or spray (Chapter 7) drying employing ChPI or LPI and maltodextrin. Effects of emulsion formulation (oil, protein and maltodextrin levels) and protein source (ChPI vs. LPI) on the physicochemical characteristics, oxidative stability, and release properties of the resulting capsules were investigated. Optimized capsule designs were found to have high encapsulation efficiencies, low surface oil, and afforded protection against oxidation over a 25 d room temperature storage study relative to free oil. Microcapsules were also able to deliver 84.2% of the encapsulated oil in the simulated gastrointestinal environments.

Orientadora: Maria Regina Barbieri de Carvalho / Banca: Elisabete Maria Macedo Viegas / Banca: Marco Antonio Trindade / Banca: Dalton José Carneiro / Banca: Hirasilva Borba Alves de Souza / Resumo: 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...(Resumo completo, clicar no acesso eletrônico abaixo) / Abstract: 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) / Doutor

Dietary fat has long been implicated in the etiology of metabolic and cardiovascular disease, and both the amount of fat and the fatty acid composition of the diet play a role in disease progression. Although national health organizations have set guidelines for the recommended intake of dietary fats, questions remain regarding the optimal dietary lipid profile for maintaining health and improving disease conditions. Whether certain types of fatty acids from plant-based oils can improve metabolic and vascular disease has been studied and debated, but not fully determined. In this study, we investigated the role of dietary fatty acids from plant-based oils, and examined their effects on metabolic and vascular disease parameters. Obese fa/fa Zucker rats were fed a diet containing flaxseed oil, which resulted in smaller adipocytes and decreased adipose tissue T-cell infiltration. Obese-prone Sprague Dawley rats were fed high-fat diets with different proportions of mono- and polyunsaturated fats. Changes were observed in adipose tissue levels of fatty acid synthase, adiponectin and fatty acid receptors GPR41 and GPR43, but other metabolic and inflammatory mediators in adipose tissue and serum remained stable. A systematic review and meta-analysis on the impact of n3 fatty acids on major cardiovascular endpoints showed that little evidence exists to support their role in peripheral arterial disease. Then again, very few studies on this topic have been conducted. To address this research gap, a clinical trial was designed to investigate the effects of a dietary intervention on blood vessel properties in people with peripheral arterial disease. Participants in the Canola-PAD Study consumed 25 g/day of canola oil or a Western diet oil mixture as part of their usual diet for 8 weeks. Although the intervention altered phospholipid fatty acids, vascular function, the lipid profile and inflammatory markers stayed relatively stable. Overall, this research demonstrates that dietary fatty acids from plant-based oils can be immunomodulatory, but at the physiological doses tested they are not potent mediators of functional changes in obesity or vascular physiology. / October 2015

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 &Delta;-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 &Delta;-6 desaturase total e atividade &Delta;-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 &Delta;-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, &Delta; 6-desaturase activity and the total &Delta; 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.

The overarching goal of this research was to formulate an encapsulated powder using a modified lentil protein isolate-maltodextrin mixture to encapsulate flaxseed oil by freeze drying. The primary objectives were: a) to examine the physicochemical and emulsifying properties of lentil protein isolates with different degrees of hydrolysis; b) to design and test the physicochemical properties of encapsulated flaxseed oil using a wall material with native, heat treated and partially hydrolyzed lentil proteins in combination with maltodextrin; and c) test the oxidative stability of encapsulated flaxseed oil with the capsule design with the lowest surface oil and highest encapsulation efficiency versus free oil. During the first study, the physicochemical and emulsifying properties of lentil protein isolates (LPI) were investigated as a function of their degree of hydrolysis (DH of 4, 9 and 20%) following exposure to trypsin/heat. Interfacial tension, surface characteristics (charge and hydrophobicity) and intrinsic fluorescence were determined and related to changes in the emulsification activity (EAI) and stability indices (ESI) of unhydrolyzed (u-LPI) and hydrolyzed LPI (h-LPI) in a flaxseed oil-water emulsion. Most importantly surface hydrophobicity declined from ~30 to ~24 for the u-LPI and h-LPI (DH 4-20%), respectively. The changes in physicochemical properties induced by hydrolysis had a detrimental effect on EAI and ESI values, which declined from ~51 to ~47 m2 g-1 and ~12 to ~ 11 min for u-LPI and h-LPI (DH 4-20%), respectively. In the second study, the physicochemical properties of encapsulated flaxseed oil within lentil protein-based maltodextrin microcapsules were investigated using native (n-LPI), pre-treated (heated, un-hydrolyzed (u-LPI); and heated, hydrolyzed (h-LPI)) lentil protein isolates and as a function of oil load (10.0, 20.0 and 30.0% of total solids). The moisture, water activity, surface oil and encapsulation efficiency (EE) were assessed, along with droplet size and emulsion morphology. Light microscopy imaging of the emulsions, showed that the h-LPI had slightly larger oil droplets than the n-LPI and u-LPI, which both appeared similar. Microcapsules prepared from h-LPI showed significantly higher surface oil and lower EE than both the n-LPI and u-LPI materials. The microcapsules prepared using n-LPI with 10.0% oil loading were found to have the lowest surface oil content (~3.7%) and highest EE (~62.8%) for all formulations, and were subjected to an oxidative storage stability test over a 30 d period vs. free oil. The encapsulation process however induced autooxidation leading the production of a greater amount of primary oxidative products than free oil. Findings indicate that future studies are necessary to enhance the stability of the flaxseed oil through the encapsulation process.

Breast cancer molecular subtypes, based on expression of estrogen, progesterone and human epidermal growth factor 2 receptors, alter prognosis and treatment options. &alpha;-linolenic acid (ALA) is a complementary therapy, however its effectiveness across breast cancer types and estrogen environments is unclear. This research determined the effect of ALA on growth, apoptosis, fatty acid profile, and gene changes in four breast cancer cell lines with varying receptor expression with or without (&plusmn;) estradiol (E2). ALA (50-200uM) &plusmn; E2 reduced growth in all cell lines. 75&mu;M ALA +E2 increased phospholipid % ALA in all cell lines and induced apoptosis in cell lines lacking the three receptors. Cellular % ALA was positively associated with apoptosis and inversely associated with cell growth. ALA altered expression of cell cycle, apoptosis and signal transduction genes. In conclusion, ALA incorporates into breast cancer cells, reduces growth and induces apoptosis regardless of receptor status or E2 level.

Breast cancer molecular subtypes, based on expression of estrogen, progesterone and human epidermal growth factor 2 receptors, alter prognosis and treatment options. &alpha;-linolenic acid (ALA) is a complementary therapy, however its effectiveness across breast cancer types and estrogen environments is unclear. This research determined the effect of ALA on growth, apoptosis, fatty acid profile, and gene changes in four breast cancer cell lines with varying receptor expression with or without (&plusmn;) estradiol (E2). ALA (50-200uM) &plusmn; E2 reduced growth in all cell lines. 75&mu;M ALA +E2 increased phospholipid % ALA in all cell lines and induced apoptosis in cell lines lacking the three receptors. Cellular % ALA was positively associated with apoptosis and inversely associated with cell growth. ALA altered expression of cell cycle, apoptosis and signal transduction genes. In conclusion, ALA incorporates into breast cancer cells, reduces growth and induces apoptosis regardless of receptor status or E2 level.