796 resultados para CHAIN FATTY-ACIDS
Resumo:
[EN]Trans fatty acids are found naturally in foods, particularly in those derived from ruminant animals, such as beef and dairy cattle. Over the past few decades, human consumption of trans fatty acids has increased, but this has been mainly from products containing partially hydrogenated vegetable oils. The correlation of trans fatty acid consumption with diseases such as coronary heart disease has been cause for concern, and led to recommendations to reduce their consumption. Trans fatty acids, however, have differing effects on human health. Therefore, in foods produced from ruminant animals, it is important to know their trans fatty acid composition, and how to enrich or deplete fatty acids that have positive or negative health effects. This review will cover the analysis of trans fatty acids in beef, their origin, how to manipulate their concentrations, and give a brief overview of their health effects.
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This study was designed to compare the quality of veal produced from ‘Tudanca x Charolais’ cross (n=6) and Limousin (n=6) breeds when allowed to feed freely on mountain pastures and suckle naturally from birth to 7 months of age. After 80 days of age calves also had access to concentrate (maximum of 3 Kg/day), while mothers did not. At slaughter, Limousin calves were heavier (P<0.01) and provided better carcass yield (P<0.05) and conformation (P<0.001) than Tudanca calves. Tudanca beef provided higher fat content (P<0.05) was less tough (P<0.05), and was scored as more tender and juicy (P<0.1) with higher acceptability than Limousin beef (P<0.1). In general, Tudanca had a better fatty acid profile than Limousin beef, especially in terms of the content of polyunsaturated (P<0.05), long-chain polyunsaturated fatty acids (P<0.05) and their n-6/n-3 ratios (P<0.1), as well as vaccenic acid (P<0.1) and the overall trans-18:1 isomer profile.
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The moisture, fat, ash, fatty acid profile, and cholesterol content are reported for cooked and raw fillets from 22 species of finfish found in the Northwest Atlantic. All but nine species had 1%or less fat. Ocean perch and a spring sampling of mackerel and wolffiSh had about 2% fat, followed by yellowfin tuna, whiting, silver hake, butterfish, and a summer -sampling of mackerel and wolffish with a range of 3-7% fat. Herring had a range of 5-12% fat representing a winter sampling on the low end and summer sampling on the high end of the range. Bluefin tuna (a summer sampling) contained the most fat with a high of 23% fat. Omega-3 fatty acids were present in excess of omega-6 fatty acids. The fattier fISh supplied the most omega-3 fatty acids per gram of tissue. The mean cholesterol content for all species was 57 ± 16 mg/l00 g raw tissue. Finfish from the Northwest Atlantic would appear to fit into the regime for a healthy heart, being low in fat and cholesterol and rich in omega-3 fatty acids.(PDF file contains 42 pages.)
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Atualmente, existe um crescente interesse por fontes de energia renováveis e o desenvolvimento de novas tecnologias para a produção de biocombustíveis. O biodiesel é uma fonte alternativa de combustível bastante atrativa em relação ao diesel em decorrência de seus benefícios ambientais. A obtenção de biodiesel é geralmente realizada através de reações de transesterificação de óleos vegetais com álcool de cadeia curta. Entretanto, também se pode produzi-lo através da esterificação de ácidos graxos livres utilizando-se matérias-primas de baixa qualidade como rejeitos industriais, domésticos ou gorduras animais. O estudo de catalisadores que melhorem os resultados destas reações tem importante papel no desenvolvimento da produção de biodiesel. Normalmente, utilizam-se catalisadores básicos como o NaOH, nas reações de transesterificação. No entanto, o uso destes catalisadores causa impactos ambientais, além de promover a reação de saponificação quando a matéria-prima apresenta teores significativos de acidez, reduzindo o rendimento e dificultando a separação de fases. Este trabalho apresenta o estudo de catalisadores ácidos, à base de estanho, com ênfase especial no sulfato de estanho II, voltados para utilização na reação de esterificação de cargas contendo elevados teores em ácidos graxos. Avaliou-se a influência das variáveis: temperatura, concentração do catalisador, tipo de sistema reacional, quantidade de etanol, tipo de álcool, acidez, natureza dos ácidos graxos e temperatura de calcinação. Uma comparação entre os catalisadores, a questão da reutilização do catalisador e das mudanças proporcionadas pelo tratamento térmico ao qual foram submetidos também foram analisadas. Dentre os catalisadores estudados, os de sulfato de estanho mostraram maior atividade catalítica frente à reação estudada, os mais promissores sendo os calcinados até a temperatura de 500C. O principal motivo para os altos rendimentos encontrados foi associado ao comportamento pseudo-homogêneo do SnSO4, que se solubiliza, acidificando o meio reacional durante as reações de esterificação
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Indivíduos obesos apresentam maior risco de morbidade e mortalidade atribuída às doenças cardiovasculares. A composição da dieta é um fator que prediz o fenótipo cardíaco em resposta a obesidade e, o tipo de ácido graxo pode afetar de forma diferencial a estrutura e a função do miocárdio. Estudos têm mostrado que a disfunção mitocondrial exerce um papel chave na patogênese da insuficiência e hipertrofia cardíaca, e as alterações mitocondriais observadas em falhas cardíacas apontam para defeitos em sítios específicos da cadeia transportadora de elétrons. Desta forma, o objetivo deste estudo foi avaliar a função contrátil ventricular em camundongos, alimentados com dieta hiperlipídica, rica em ácidos graxos poliinsaturados, buscando elucidações através da bioenergética mitocondrial. Após desmame, camundongos machos C57Bl/6 passaram a receber dieta manipulada contendo 7% (C) ou 19% (HF) de óleo de soja, até os 135 dias de idade. A ingestão alimentar e a massa corporal foram monitoradas e foi realizado teste de tolerância à glicose. No final do período experimental, os animais foram anestesiados e submetidos à avaliação da composição corporal por Absortimetria de Raios X de Dupla Energia (DXA), e em seguida, sacrificados por exsanguinação. No plasma foram determinados o perfil lipídico e a insulina. O coração, o tecido adiposo intra-abdominal e o subcutâneo foram coletados, pesados, processados para análise histomorfológica. Fibras cardíacas do ventrículo esquerdo foram utilizadas para análise da respiração mitocondrial através de oxígrafo. O coração também foi utilizado para a técnica de perfusão de coração isolado de Langendorff, e para análise da expressão de proteínas relacionadas à bioenergética de cardiomiócitos, através de Western Blotting. O índice de HOMA e de adiposidade foram calculados. O grupo HF apresentou maior adiposidade, sem alteração na ingestão alimentar. Foi observada intolerância a glicose, hiperinsulinemia e resistência à insulina, além de alterações desfavoráveis no perfil lipídico. Foi observado alteração na morfologia cardíaca e quadro de cardiomiopatia hipertrófica, refletindo em alteração hemodinâmica, determinando maior contratilidade, maior pressão ventricular e função diastólica prejudicada. Em relação à atividade mitocondrial dos cardiomiócitos foi observada menor oxidação de carboidratos (-47%) e de ácidos graxos (-60%). Porém, sem alteração na expressão de proteínas relacionadas à bioenergética de cardiomiócitos, CPT1, UCP2, GLUT1, GLUT4, AMPK e pAMPK. A partir desses resultados, concluímos que o tipo e a quantidade de ácidos graxos predizem o fenótipo cardíaco na obesidade, promovendo alteração na capacidade oxidativa mitocondrial, na morfologia e na hemodinâmica cardíaca
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In order to accurately assess the influence of fatty acids on the hygroscopic and other physicochemical properties of sea salt aerosols, hexanoic, octanoic or lauric acid together with sodium halide salts (NaCl, NaBr and NaI) have been chosen to be investigated in this study. The hygroscopic properties of sodium halide sub-micrometre particles covered with organic acids have been examined by Fourier-transform infrared spectroscopy in an aerosol flow cell. Covered particles were generated by flowing atomized sodium halide particles (either dry or aqueous) through a heated oven containing the gaseous acid. The obtained results indicate that gaseous organic acids easily nucleate onto dry and aqueous sodium halide particles. On the other hand, scanning electron microscopy (SEM) images indicate that lauric acid coating on NaCl particles makes them to aggregate in small clusters. The hygroscopic behaviour of covered sodium halide particles in deliquescence mode shows different features with the exchange of the halide ion, whereas the organic surfactant has little effect in NaBr particles, NaCl and NaI covered particles experience appreciable shifts in their deliquescence relative humidities, with different trends observed for each of the acids studied. In efflorescence mode, the overall effect of the organic covering is to retard the loss of water in the particles. It has been observed that the presence of gaseous water in heterogeneously nucleated particles tends to displace the cover of hexanoic acid to energetically stabilize the system.
Evaluation of the contribution of fisheries and aquaculture to food security in developing countries
Resumo:
Fish contain important nutrients such as essential fatty acids, iron, zinc, calcium, vitamin A and vitamin C. Production of freshwater fish depends on the strategic application of various management techniques. The demand for fish products has increased beyond the natural supply, resulting in a high pressure on fisheries. Development of aquaculture is necessary for a rapid growth in fish production. A number of constraints hamper the development of aquaculture. Introduction of polyculture technologies in some countries is a way of maximizing production from different levels of the food chain. The roles of women in making fish products available to consumers is frequently over-looked by policy makers. Gender equity in policy-making and management of fisheries and in capacity building is an important issue. Fish production from inland waters and coastal areas can be increased by adopting cage and pen culture systems. Input subsidies and loans to resource poor farmers can boost fish production.
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Recent research by the authors evaluated strategies to reduce fishmeal and fish oil in diets for red drum by substituting terrestrial proteins and lipids while maintaining beneficial fatty acids with DHA supplements derived from marine algae. Results suggested fatty acid-enriched finishing diets can be used with growout diets containing little or no fishmeal and fish oil to achieve the desired DHA content in the final fish fillets.
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Gas-liquid chromatography has been employed for the qualitative and quantitative analysis of the component fatty acids in lipids of oil sardine (Sardinella longiceps). Phospholipids and triglycerides of the lipids were previously separated by column chromatography before they were converted into the methyl esters of the fatty acids. The predominant acids present in the depot fat of the fish have been found to be C14:0=8.13%, C16:0=27.9%, C18:0=3.8%, C18:1=15.4%., C20:5=10.6% and C22:6=8.8%. Apart from the above acids the distribution of minor acids belonging to Cl8, C20 and C22 groups have also been worked out. The separated phospholipid fraction contained more than 70% polyunsaturated acids of which the important constituents were docosahexaenoic (C22:6=28%) and eicosapentaenoic (C20:5=10.6%). A marked reduction was found in the amounts of polyunsaturated acids in triglycerides, their total amount registering about 20%. This fraction recorded about 48% of C16 acids of which palmitic and palmitoleic acids amounted to 25.8% and 19.1% respectively. Occurrence of odd numbered fatty acids C15 and C17 has also been noted in the phospholipid and composite samples of the fish.
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Fatty acid composition of freshwater fish tilapia, (Tilapia mosambica), barbus (Barbus carnaticus) and Varal (Ophicephalus) is determined by gas-liquid chromatography. Varal contained the highest amount of C sub(20:5) acid compared to other 2 spp. Of the odd-numbered fatty acids C sub(17) was the predominant fatty acid present. Palmitic acid was found to have a lower level in these fish compared to marine fish. Barbus recorded unusually high percentage of 23.3% of C sub(18:2) acid.
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A study was made to elucidate fatty acid composition of Anchoviella and Thrissocleus, and bring to light similarities with other clupeids. The results are tabulated. The polyunsaturated fatty acids, eicosapentaenoic acid and docosahexaenoic acid, are the 2 major fatty acids in the phospholipid fraction of both fish. Myristic, palmitic and stearic acids are the major components of the nonphosphorylated fraction.
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The influence of sex, spawning, starvation and water temperature on the fatty acid composition of Tilapia mossambica has been studied. Tilapia egg lipid was found to have unusually high percentage of C sub(22:6) fatty acids (9.09%) compared to body and intestinal lipids. The C sub(16:1) acid was much less in the egg lipids (3.5%) whereas it was 11% in the body lipids. There was no significant difference in the fatty acid composition of body and intestinal lipids of male and female tilapia. Starvation caused the presence of high content of lower fatty acids (C sub(6), C sub(8), C sub(30), C sub(12) and C sub(33)) in the body lipids. Water temperature also influenced the fatty acid composition of Tilapia; the difference was more significant in body lipids than in intestinal lipids.
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The present study aimed production of a new product with various texture and sensory properties in chase of the impetus for increasing human consumption considering suitable resources of Kilka fish in Caspian Sea. Following deheading, gutting, and brining, common Kilka were battered in two different formulations, i.e. simple batter and tempura batter, via automated predusting machinery and then, they were fried through flash frying for 30 seconds at 170°C in sunflower oil after they were breaded with bread crumbs flour. The products were subjected to continuous freezing at -40°C and were kept at -18°C in cold storage for four months once they were packed. Chemical composition (protein, fat, moisture, and ash), fatty acid profiles (29 fatty acids), chemical indices of spoilage (peroxide value, thiobarbituric acid, free fatty acids, and volatile nitrogen), and microbial properties (total bacteria count and coliform count) were compared in fresh and breaded Kilka at various times before frying (raw breaded Kilka), after frying (zero-phase), and in various months of frozen storage (phases 1, 2, 3, and 4). Organoleptic properties of breaded Kilka (i.e. odor, taste, texture, crispiness, cohesiveness of batter) and general acceptability in the phases 0, 1, 2, 3, and 4 were evaluated. The results obtained from chemical composition and fatty acid profiles in common Kilka denoted that MUFA, PUFA, and SFA were estimated to be 36.96, 32.85, and 29.12 g / 100g lipid, respectively. Levels of ù-3 and ù-6 were 7.6 and 1.12 g / 100 gr lipid, respectively. Docosahexaonoic acid (20.79%) was the highest fatty acid in PUFA group. ù-3/ù-6 and PUFA/SFA ratios were 7.6 and 1.12, respectively. The high rates of the indices and high percentage of ù-3 fatty acid in common Kilka showed that the fish can be considered as invaluable nutritional and fishery resources and commonsensical consumption of the species may reduce the risk of cardiovascular diseases. Frying breaded Kilka affected overall fat and moisture contents so that moisture content in fried breaded Kilka decreased significantly compared to raw breaded Kilka, while it was absolutely reverse for fat content. Overall fat content in tempura batter treatment was significantly lower than that of simple batter treatment (P≤0.05). Presence of hydrocolloids, namely proteins, starch, gum, and other polysaccharides, in tempura batter may prohibit moisture evaporation and placement with oil during frying process in addition to boosting water holding capacity through confining water molecules. During frying process, fatty acids composition of breaded Kilka with various batters changed so that rates of some fatty acids such as Palmitic acid (C16:0), Stearic acid (C18:0), Oleic acid (C18:1 ù-9cis), and linoleic acid (C18:3 ù-3) increased considerably following frying; however, ù-3/ù-6, PUFA/SFA, and EPA+DHA/C16:0 ratios (Polyan index) decreased significantly after frying. ù-3/ù-6, PUFA/SFA, and EPA+DHA/C16:0 ratios in tempura batter treatment were higher than those of simple batter treatment which is an indicator of higher nutritional value of breaded Kilka with tempura batter. Significant elevations were found in peroxide, thiobarbituric acid, and free fatty acids in fried breaded Kilka samples compared to raw samples which points to fat oxidation during cooking process. Overall microorganism count and coliform count decreased following heating process. Both breaded Kilka samples were of high sanitation quality at zero-phase according to ICMSF Standard. The results acquired from organoleptic evaluation declared that odor, cohesiveness, and general acceptability indices, among others, had significant differences between the treatments (P≤0.05). In all evaluated properties, breaded Kilka with tempura batter in different phases gained higher scores than breaded Kilka with simple batter. During cold storage of various treatments of breaded Kilka, total lipid content, PUFA, MUFA, ù-3, ù- 3/ù-6, PUFA/SFA, Polyen index decreased significantly. The mentioned reductions in addition to significant elevation of spoilage indices, namely peroxide, thiobarbituric acid, and free fatty acids, during frozen storage, indicate to oxidation and enzymatic mechanism activity during frozen storage of breaded Kilka. Considering sensory evaluation at the end of the fourth month and TVB-N contents exceeded eligible rate in the fourth month, shelf life of the products during frozen storage was set to be three months at -18°C. The results obtained from statistical tests indicate to better quality of breaded Kilka processed with tempura batter compared to simple batter in terms of organoleptic evaluation, spoilage indices, and high quality of fat in various sampling phases.
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A study was carried out with three replicates to determine the effects of feeding Moina micrura enriched with astaxanthin alone (M1) or astaxanthin in combination with either vitamin E (M2), vitamin D (M3) or Cod Liver oil (M4) on the growth, survival and fatty acid composition of giant fresh water prawn Macrobrachium rosenbergii (de Man) larvae. Growth rate was expressed as the time taken to the settlement of 95% post larvae. Maximum growth, the lowest time taken to the 95% PL settlement (38.5±0.50 days), was observed in larvae fed with M3 Moina. The highest survival rate (66.0±1.00%) was observed in those fed with M4 Moina and the second highest survival (61.0±1.00%) and growth rates (40.0±0.00 days) were shown with M2 Moina. The minimum values for both growth (42.5±0.50 days) and survival (33.0±1.50%) were observed in the group fed un-enriched Moina. Results also showed that the survival of prawn larvae increased as the quantities of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) increased in the dietary Moina. The highest levels of EPA (5.57±0.21%), DHA (3.50±0.21%) and highest total Highly Unsaturated Fatty Acids (HUFA) (13.87±0.68%) were seen in the Moina fed on astaxanthin and Cod Liver Oil (CLO). The results of the study showed that the nutritive quality of Moina, with respect to important fatty acids, can be increased by enrichment and will influence the growth, survival and the fatty acid composition of fresh water prawn larvae fed on them.
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In this experiment, the feeding of Indian white shrimp larvae by unenriched rotifers (treatment 1) and enriched with highly unsaturated fatty acid (treatment 2) and highly unsaturated fatty acid along with vitamin C (treatment 3) on the growth factors, survival and resistance against salinity and formalin stress tests were studied and their differences with control treatment including newly hatched Artemia nauplii is compared. In this the study four treatments in a completely randomized design with 3 replicates per treatment were used. Farming of shrimp larvae of Zoea II to postlarvae 5 was done in 20 liter plastic bucket. Present results indicated that growth factors and survival rate of stage Zoea II to postlarvae 1 in treatments 1, 2 and 3 improve rather than control in which this case was due to optimal size rotifer rather than Artemia nauplii. Also, treatments 2 and 3 feeding with oil liver cod emulsion enriched rotifer have the highest concentration of DHA (mg/g DW) and the ratio DHA/EPA in which due to have shown the highest growth factors and a significant difference (P<0.05) with treatments 1 and control. The highest survival at stage PL1 were observed in treatment 3 that was enriched with ascorbyl palmitate in which have to the synergistic properties of vitamin C rather than treatments 2, 1 and control and showed a significant difference (P<0.05). But in stage PL5 the highest amount of growth and survival rates were related to control treatment which showed a significant difference (P<0.05) with other treatments that control has higher size rather than treatments 1, 2 and 3. Also, among experiment treatments that the two treatments 2 and 3 due to enrichment had higher growth and survival rates compared with treatment 1 in which their differences have also been significant (P<0.05). In the case of stress tests, results indicated that the highest survival rate has been reported when specimens were offered a diet containing high levels of highly unsaturated fatty acids with vitamin C. So that in stage PL1 in the salinity stress tests 10 and 20 ppt the highest survival rate was observed in treatment 3. As for the second, treatment 2 showed a significant difference (P<0.05) with treatment 3. It is worth mentioning that treatment 3 showed a higher survival rate compared to treatment 2 due to the synergistic properties of vitamin C. The difference between these two treatments with treatment 1 and control was also significant. No significant difference was observed in formalin stress test 100 ppm in this stage between treatments 3 and 2 which shows the highest survival rate. But their difference with treatments 1 and control was significant (P<0.05). Also, in stage PL5 in the salinity stress tests 10 and 20 ppt the highest survival rate was observed in treatment 3 which showed no significant difference (P<0.05) with control treatment. While their difference in the amount of survival rate with treatment 1 and 2 was significant (P<0.05). In this stage, the highest observed survival rate in formalin stress test 100 ppm included treatments control, 3 and 2 among which there were no significant differences (P<0.05). While the difference between these three treatments with treatment 1 was significant.