736 resultados para omega-3 fatty acids


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In this work the separation of multicomponent mixtures in counter-current columns with supercritical carbon dioxide has been investigated using a process design methodology. First the separation task must be defined, then phase equilibria experiments are carried out, and the data obtained are correlated with thermodynamic models or empirical functions. Mutual solubilities, Ki-values, and separation factors aij are determined. Based on this data possible operating conditions for further extraction experiments can be determined. Separation analysis using graphical methods are performed to optimize the process parameters. Hydrodynamic experiments are carried out to determine the flow capacity diagram. Extraction experiments in laboratory scale are planned and carried out in order to determine HETP values, to validate the simulation results, and to provide new materials for additional phase equilibria experiments, needed to determine the dependence of separation factors on concetration. Numerical simulation of the separation process and auxiliary systems is carried out to optimize the number of stages, solvent-to-feed ratio, product purity, yield, and energy consumption. Scale-up and cost analysis close the process design. The separation of palmitic acid and (oleic+linoleic) acids from PFAD-Palm Fatty Acids Distillates was used as a case study.

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Conjugated fatty acid (CFA) is the general term to describe the positional and geometric isomers of polyunsaturated fatty acids with conjugated double bonds. The CFAs of linoleic acid (CLAs) are found naturally in foods derived from ruminant animals, meat, or dairy products. The CFAs of α-linolenic acid (CLNAs) are found exclusively in various types of seed oils of plants. There are many investigations to assess the effects to health from CFAs consumption, which have been associated with physiological processes that are involved with non transmissible chronic diseases such as cancer, atherosclerosis, inflammation, and obesity. Conclusive studies about the CFAs effects in the body are still scarce and further research about their participation in physiological processes are necessary. This review aimed to discuss the influence of conjugated fatty acids on physiological processes in animal organism.

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Due to the adverse effects of the cholesterol oxidation products for the human health, the search of the occurrence and the quantification of these compounds in foods are considered of great importance. In this paper the effect of grilling in hake and sardine on cholesterol oxides formation and fatty acids alterations was investigated. The main fatty acids determined in both fishes were docosahexaenoic (DHA), oleic, eicosapentaenoic (EPA) and palmitoleic. The total lipids, fatty acids and cholesterol contents were decreased significantly (p < 0.02) after thermal treatment, with simultaneous increase of the cholesterol oxides contents. The cholesterol oxides determined in both species in the present study were: 19-hydroxycholesterol, 24(S)-hydroxycholesterol, 22(S) hydroxycholesterol, 25-hydroxycholesterol, 25(R)-hydroxycholesterol and 7-ketocolesterol. Besides the presence of the cholesterol oxides in raw fishes, there were a greater number of products resulting from the oxidation of cholesterol side chain, a fact rarely observed in foods.

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The effect of gamma irradiation (0, 2, 4, and 6 kGy doses) applied to frozen and packed headed shrimp on the fatty acid profile, cholesterol content, and lipid and color stability was evaluated. Myristic acid was higher in shrimp irradiated with 4 and 6 kGy and palmitic acid was higher in samples irradiated with 2 and 6 kGy compared to non-irradiated samples. Stearic and behenic acids were lower in shrimp irradiated with 6 kGy compared to non-irradiated shrimp. With regard to non-irradiated shrimp, palmitoleic, oleic, and linoleic acids and total monounsaturated fatty acids were higher in shrimp irradiated with 6 kGy. Saturated fatty acid and cholesterol contents in irradiated samples were not different from those in non-irradiated shrimp. Lipid oxidation was higher in samples irradiated with 2, 4, and 6 kGy. Redness and yellowness of cooked shrimp were higher in samples irradiated with 6 kGy than in those in non-irradiated samples. The application of irradiation in doses up to 6 kGy on frozen and packed headed shrimp does not affect negatively the fatty acid profile, cholesterol content, and lipid and color stability.

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The objective of the present study was to characterize the centesimal composition and quantify fatty acids in regular and diet chocolate brands with emphasis on trans fatty acids. Regular and diet dark chocolate samples from the major brands analyzed were purchased from different local supermarkets in the city of Maringá. The brands were labeled with letters and five lots of each brand with three chocolate units per lot were analyzed in triplicate. We observed that the diet chocolates from the same brands presented larger lipid contents. The main fatty acids observed were saturated fatty acids (SFA), myristic acid (14:0), palmitic acid (16:0), and estearic acid (18:0). Among the monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA) and trans fatty acids, oleic acid (18:1n-9), linoleic acid (18:2n-6), and elaidic acid (18:1-9t) predominated. The trans fatty acid contents found in the analyzed samples were lower than and/or in accordance with the limits proposed by the Brazilian regulation.

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Brazil is one of the three largest producers of fruits in the world, and among those fruit trees, the cashew tree stands out due to the high nutritional and commercial value of its products. During its fruit processing, there are losses in some compounds and few studies address this issue. Over the last decade the conventional system of food production has been substituted for the organic cultivation system, which is a promising alternative source of income given the global demand for healthy food. Therefore, this research aimed to characterize and quantify the prevalent fatty acids found in cashew nuts obtained from conventional and organic cultivation during various stages of processing. The prevalent fatty acids found were palmitic, linoleic, oleic, and stearic acid. The average of these fatty acids were 6.93 ± 0.55; 16.99 ± 0.61; 67.62 ± 1.00 and 8.42 ± 0.55 g/100 g, respectively. There was no reduction in the palmitic, oleic and stearic fatty acid contents during processing. Very little difference was observed between the nuts obtained from conventional and organic cultivation, indicating that the method of cultivation used has little or no influence on the content of cashew nut fatty acids.

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Thesis (M.Sc.)--Brock University, 1979.

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Affiliation: CHU-Sainte-Justine, Université de Montréal

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Candida albicans est une levure pathogène qui, à l’état commensal, colonise les muqueuses de la cavité orale et du tractus gastro-intestinal. De nature opportuniste, C. albicans cause de nombreuses infections, allant des candidoses superficielles (muguet buccal, vulvo-vaginite) aux candidoses systémiques sévères. C. albicans a la capacité de se développer sous diverses morphologies, telles que les formes levures, pseudohyphes et hyphes. Des stimuli environnementaux mimant les conditions retrouvées chez l’hôte (température de 37°C, pH neutre, présence de sérum) induisent la transition levure-à-hyphe (i.e. morphogenèse ou filamentation). Cette transition morphologique contribue à la pathogénicité de C. albicans, du fait que des souches présentant un défaut de filamentation sont avirulentes. Non seulement la morphogenèse est un facteur de virulence, mais elle constituerait aussi une cible pour le développement d’antifongiques. En effet, il a déjà été démontré que l’inhibition de la transition levure-à-hyphe atténuait la virulence de C. albicans lors d’infections systémiques. Par ailleurs, des études ont démontré que de nombreuses molécules pouvaient moduler la morphogenèse. Parmi ces molécules, certains acides gras, dont l’acide linoléique conjugué (CLA), inhibent la formation d’hyphes. Ainsi, le CLA posséderait des propriétés thérapeutiques, du fait qu’il interfère avec un déterminant de pathogénicité de C. albicans. Par contre, avant d’évaluer son potentiel thérapeutique dans un contexte clinique, il est essentiel d’étudier son mode d’action. Ce projet vise à caractériser l’activité anti-filamentation des acides gras et du CLA et à déterminer le mécanisme par lequel ces molécules inhibent la morphogenèse chez C. albicans. Des analyses transcriptomiques globales ont été effectuées afin d’obtenir le profil transcriptionnel de la réponse de C. albicans au CLA. L’acide gras a entraîné une baisse des niveaux d’expression de gènes encodant des protéines hyphes-spécifiques et des régulateurs de morphogenèse, dont RAS1. Ce gène code pour la GTPase Ras1p, une protéine membranaire de signalisation qui joue un rôle important dans la transition levure-à-hyphe. Des analyses de PCR quantitatif ont confirmé que le CLA inhibait l’induction de RAS1. De plus, le CLA a non seulement causé une baisse des niveaux cellulaires de Ras1p, mais a aussi entraîné sa délocalisation de la membrane plasmique. En affectant les niveaux et la localisation cellulaire de Ras1p, le CLA nuit à l’activation de la voie de signalisation Ras1p-dépendante, inhibant ainsi la morphogenèse. Il est possible que le CLA altère la structure de la membrane plasmique et affecte indirectement la localisation membranaire de Ras1p. Ces travaux ont permis de mettre en évidence le mode d’action du CLA. Le potentiel thérapeutique du CLA pourrait maintenant être évalué dans un contexte d’infection, permettant ainsi de vérifier qu’une telle approche constitue véritablement une stratégie pour le traitement des candidoses.

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The effects of feeding of 6-propyllhiouracil (6-I'fU) and potyunsaturatcd fatty acids (I'UFA) independently and ill combination and administration (ip) of a single close of Iriiodothyronine (I',) (2.51ig/IOOg body wl) along with feeding of 6- PTU and PUFA were studied in cal brain. Dopamine (DA), 5-hydroxytryplophan (5-IIl'I'), serolouin (5-Ill), 5-hydioxy indole acetic acid (5-111AA), norepinephrine (NF) :uul ceinephrinn (I?I'l) contenls were assayed in the hypothalannls and ccrc bral cortex regions. It was found that 6-P"l'U Iccding resulted in decrease in dopamine, 5-III', 5 II I I' and 5 IIiAA in both regions. In animals fed wills PUFA followed by adnliuislralion of T,. the I)A level was found normal.

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The biogeochemistry of mangroves are the least understood ecological properties because of their sediment complexicity due to the tidal influx of allochthonous organic matter and the autochthonous inputs.In order to understand the relative importance of biogeochemical processes,it is necessary not only to characterise and qualify the organic matter but also to identify its major sources .The present study is a preliminary investigation to identify the sources of organic matter in three mangrove systems of Cochin Estuary using fatty acid biomarkers,δ13 C of total organic matter,elemental composition and biochemical composition.

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There is currently considerable interest in potential atherogenic and thrombogenic consequences of elevated concentrations of triacylglycerols, especially in the post-prandial state. Despite this, there is limited information on the effects of dietary fatty acids on the synthesis, secretion and metabolism of chylomicrons, the large triacylglycerol-rich lipoproteins synthesized in the enterocyte following the digestion and absorption of dietary fat. This brief review considers current approaches to the investigation of chylomicron synthesis and summarizes some of the human, cell and animal studies that have investigated effects of different fatty acids on these pathways. Potential sites for modulatory effects of dietary fatty acids on the molecular events of chylomicron synthesis are proposed in the light of the recent model that has been developed from cell and animal studies and observations based on abnormalities in chylomicron formation in human inherited autosomal recessive diseases.

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The present study investigated whether consuming dairy products naturally enriched in cis-9, trans-11 (c9,t11) conjugated linoleic acid (CLA) by modification of cattle feed increases the concentration of this isomer in plasma and cellular lipids in healthy men. The study had a double-blind cross-over design. Subjects aged 34-60 years consumed dairy products available from food retailers for 1 week and then either control (0.17 g c9,t11 CLA/d; 0.31 g trans-vaccenic acid (tVA)/d) or CLA-enriched (1.43 g c9,t11 CLA/d; 4.71 g tVA/d) dairy products for 6 weeks. After 7 weeks washout, this was repeated with the alternate products. c9,t11 CLA concentration in plasma lipids was lower after consuming the control products, which may reflect the two-fold greater c9,t11 CLA content of the commercial products. Consuming the CLA-enriched dairy products increased the c9,t11 CLA concentration in plasma phosphatidylcholine (PC) (38 %; P=0.035), triacylglycerol (TAG) (22 %; P < 0.0001) and cholesteryl esters (205 %; P < 0.0001), and in peripheral blood mononuclear cells (PBMC) (238 %; P < 0.0001), while tVA concentration was greater in plasma PC (65 %; P=0.035), TAG (98 %; P=0.001) and PBMC (84 %; P=0.004). Overall, the present study shows that consumption of naturally enriched dairy products in amounts similar to habitual intakes of these foods increased the c9,t11 CLA content of plasma and cellular lipids.

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Clinical and biomedical studies have provided evidence for the critical role of n-3 fatty acids on the reduction of chronic disease risk in humans, including cardiovascular disease. In the current experiment, the potential to enhance milk n-3 content in two breeds with inherent genetic differences in mammary lipogenesis and de novo fatty acid synthesis was examined using extruded linseeds. Six lactating cows (three Holstein and three Jersey) were used in a two-treatment switchback design with 3 × 21-day experimental periods to evaluate the effect of iso-energetic replacement of calcium salts of palm oil distillate (CPO) in the diet (34 g/kg dry matter (DM)) with 100 g/kg DM extruded linseeds (LIN). For both breeds, replacing CPO with LIN had no effect (P > 0.05) on DM intake or milk yield, but reduced (P < 0.05) milk fat and protein yield (on average, from 760 to 706 and 573 to 552 g/day, respectively). Relative to CPO, the LIN treatment reduced (P < 0.01) total saturated fatty acid content and enhanced (P < 0.001) 18:3n-3 in milk, whereas breed by diet interactions were significant for milk fat 16:0, total trans fatty acid and conjugated linoleic acid concentrations. Increases in 18:3n-3 intake derived from LIN in the diet were transferred into milk with a mean marginal transfer efficiency of 1.8%. Proportionate changes in milk fatty acid composition were greater in the Jersey, highlighting the importance of diet–genotype interactions on mammary lipogenesis. More extensive studies are required to determine the role of genotype on milk fat composition responses to oilseeds in the diet.