62 resultados para food composition
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This article updates the Brazilian database on food carotenoids. Emphasis is on carotenoids that have been demonstrated important to human health: alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein and zeaxanthin. The sampling and sample preparation strategies and the analytical methodology are presented. Possible sources of analytical errors, as well as the measures taken to avoid them, are discussed. Compositional variation due to such factors as variety/cultivar, stage of maturity, part of the plant utilized, climate or season and production technique are demonstrated. The effects of post-harvest handling, preparation, processing and storage of food on the carotenoid composition are also discussed. The importance of biodiversity is manifested by the variety of carotenoid sources and the higher levels of carotenoids in native, uncultivated or semi-cultivated fruits and vegetables in comparison to commercially produced crops. (C) 2008 Elsevier B.V. All rights reserved.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Total and individual carotenoid concentrations were determined by spectro photometry and HPLC, in raw tubers of a sample of 23 accessions of Solanum phureja potatoes taken at random from the world germplasm collection following its stratification on tuber flesh color. Lutein, zeaxanthin, violaxanthin, antheraxanthin and beta-carotene were detected in all accessions and three distinct patterns of carotenoid accumulation were evidenced by cluster analysis. Accessions in group 1 showed the highest concentrations of total carotenoids (1258-1840 mu g 100 g(-1) FW) comprised largely of zeaxanthin (658-1290 mu g 100 g(-1) FW) with very low or no presence of beta-carotene (below 5.4 mu g 100 g(-1) FW). Accessions in group 2 presented moderate total carotenoid concentrations with violaxanthin, antheraxanthin, lutein and zeaxanthin as the major carotenoids. Accessions in group 3 showed low concentrations of total carotenoids (97-262 mu g 100 g(-1) FW) and very low or no zeaxanthin, with lutein and violaxanthin as the predominant carotenoids and relatively high concentrations of beta-carotene(up to 27 mu g 100 g(-1) FW). Five accessions with significant concentrations of zeaxanthin were identified with the accession 703566 showing the highest concentration (1290 p g 100 g(-1) FW). This value is to our knowledge higher than any value previously reported for potatoes, including those achieved through genetic modification. For the 23 S. phureja accessions, total carotenoid concentration was positively and significantly correlated with antheraxanthin and zeaxanthin concentrations, and negatively and significantly correlated with beta-carotene concentration. (C) 2008 Elsevier B.V. All rights reserved.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The electrochemical oxidation of caffeic, chlorogenic, sinapic, ferulic and p-coumaric acids was investigated by cyclic voltammetry on acetate buffer pH 5.6 on glassy carbon electrode and modified glassy carbon electrode. According to their voltammetric behavior, the antioxidant activity of these phenolic acids was evaluated and the results pointed to the following sequence: caffeic acid (E-a = +0.31 V) > chlorogenic acid (+ 0.38 V) > sinapic acid (+ 0.45 V) > ferulic acid (+ 0.53 V) >p-coumaric acid (+ 0.73 V). The results were confirmed by DPPH test, which evidenced the strongest antiradical activity for compounds possessing the cathecol moiety (caffeic and chlorogenic acids). Linear calibration graphs were obtained for their determination at concentrations from 1 x 10(-4) to 1 x 10(-3) mol L-1. The method was applied to orange juice. Selectivity was illustrated by the analysis of caffeic and chlorogenic acids electrodeposited on a glassy carbon electrode previously modified by electrochemical activation in the presence of ascorbic acid. (C) 2003 Elsevier B.V. All rights reserved.
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Carotenoids are natural pigments which are synthesized by plants and are responsible for the bright colors of various fruits and vegetables. There are several dozen carotenoids in the foods that we eat, and most of these carotenoids have antioxidant activity. β-carotene has been best studied since, in most countries it is the most common carotenoid in fruits and vegetables. However, in the U.S., lycopene from tomatoes now is consumed in approximately the same amount as β-carotene. Antioxidants (including carotenoids) have been studied for their ability to prevent chronic disease. β-carotene and others carotenoids have antioxidant properties in vitro and in animal models. Mixtures of carotenoids or associations with others antioxidants (e.g. vitamin E) can increase their activity against free radicals. The use of animals models for studying carotenoids is limited since most of the animals do not absorb or metabolize carotenoids similarly to humans. Epidemiologic studies have shown an inverse relationship between presence of various cancers and dietary carotenoids or blood carotenoid levels. However, three out of four intervention trials using high dose β- carotene supplements did not show protective effects against cancer or cardiovascular disease. Rather, the high risk population (smokers and asbestos workers) in these intervention trials showed an increase in cancer and angina cases. It appears that carotenoids (including β-carotene) can promote health when taken at dietary levels, but may have adverse effects when taken in high dose by subjects who smoke or who have been exposed to asbestos. It will be the task of ongoing and future studies to define the populations that can benefit from carotenoids and to define the proper doses, lengths of treatment, and whether mixtures, rather than single carotenoids (e.g. β-carotene) are more advantageous.
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Thirty 3/4 Canchim + 1/4 Nelore young bulls with 417 kg of body weight and 15 months of age, were confined during 84 days. The animals were fed with diets composed with corn silage, corn grain, cottonseed meal, soybean meal, whole soybean and mineral mix, adjusted in agreement with the recommendations of the Metabolizable Protein System (MP), Cornell Net Carbohydrate and Protein System (CNCPS) and Intestine Digestible Protein System (PDI), for predicted body weight gain of 1.3 kg/head/day. The daily body weight gain did not differ among treatments CNCPS, MP and PDI, with 1.51; 1.48; and 1.13 kg/head, respectively. The economic analysis revealed net profit of R$116.25; R$148.30; and R$108.51/head for CNCPS, MP and PDI systems, respectively. The diets adjusted by CNCPS and MP systems provided superior animal performance than that expected, while the diet adjusted by PDI system did not allow the predicted body weight gain.
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The aim of this study is to determine the natural abundance of carbon stable isotope (13C) of some food components and determine its contribution to the pintado juvenile growth, in laboratory conditions. 150 fishes were used with average weight of 1.39 g, and stocked in two net ponds with 125L each, during 60 days. Every 10 days a water sample was collected to analyse phytoplakton and zooplankton. Clacocera was dominant in the analysis of the stomach contents, following Chironomidae and Copepoda. A fish sample was collected in the beginning, and at the end of the experiment to analyses the isotopic signal. An average value of -20.94; -15.36 and -18.81 δ13C%o was obtained for phytoplankton, Cladocera and Chironomidae, respectively. Cladocera was the main carbon source and contribution with carbon average 89.24% in feeding this species, while the Chironomid contribution was 10.76%. The δ13C was effective as carbon tracer in food chain, because the consumer reflects its diet isotopicly.
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Most studies on the antioxidants, lipoic acid (LA) and ascorbic acid (AA), focused on species that, unlike teleost fish, are not scurvy-prone, and are able to synthesize AA. The antioxidant properties of LA may make it useful in aquaculture nutrition, but several effects must first be investigated, and we address here plasma free amino acids (FAA). In mammals, LA and AA in high doses were claimed to alter plasma FAA profile; to our knowledge, however, no data are available in fish. We therefore studied the effects of dietary LA and AA on plasma FAA in the South American teleost fish pacu, which is being used increasingly in aquaculture. LA treatment decreased concentrations of 18 of 23 individual FAA; specifically, dispensable and total FAA were significantly affected. Ornithine was elevated (+26%) in LA-treated fish and significantly decreased ratios of plasma [Arg]/[Orn] and other individual [FAA]/[Orn] were observed. LA and AA both affected sulfur FAA concentrations. Plasma cystine levels were significantly increased in the LA-supplemented groups. AA had little effect on most amino acids, and no interaction with LA was detected. AA supplementation did, however, significantly lower taurine (-42%) and cystathionine (-31%) levels in plasma. No effect on the branched chain:aromatic amino acid ratios was observed. The data indicate that at the dietary level studied, LA and AA independently affect selected plasma FAA in pacu, and suggest that any use of LA in particular as a dietary supplement should take into account an altered plasma FAA profile.
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Effects of dietary α-lipoic acid (LA) and ascorbic acid (AA) on the growth, tissue vitamin C and tocopherol (vitamin E) levels, and malondialdehyde levels were examined in the tropical fish pacu, Piaractus mesopotamicus. Pacu juveniles were fed one of four casein-gelatin-based diets for 8 weeks: with 0.05% AA and 0.1% LA (+AA+LA), with AA and without LA (+AA-LA), without AA and with LA (-AA+LA), and without AA and LA (-AA-LA). When the fish received quantities of feed equal to 1.9-2.5% of its body weight, growth was not influenced, regardless of the presence of AA or LA throughout most of the experimental period. Growth was, however, slightly but significantly lower at week 8 in the AA-deficient/LA-supplemented group. An AA-deficient diet caused a highly significant reduction in both total AA and dehydroascorbic acid content in the liver and gill tissues. This reduction of tissue AA concentrations was reversed in a significant manner by LA (antioxidant-sparing effect). The 8-week-long vitamin C deprivation was sufficient to initiate the reduction in tissue ascorbic acid; however, total ascorbate in the liver of fish in the (-)AA/(+)LA group was 127.7±54.3 nmol g-1 tissue, whereas it was 28.6±26.3 nmol g-1 in the (-)AA/(-)LA group, a 4.4-fold difference. This mitigating effect of the addition of the endogenous antioxidant LA to the diet indicates that LA exerts a vitamin C-sparing effect in teleost fish that by far exceeds the phenomena demonstrated in non-scurvy-prone mammals. There was no difference among the different diet groups for vitamin E and malondialdehyde levels in the liver. These results suggest that LA is a potent substance for the prevention of AA deficiency in cultured fishes. The optimal dietary level of LA needs to be determined in the light of the slight reduction in body weight gain after 8 weeks of feeding in the absence of AA. © Springer Science+Business Media, Inc. 2006.
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In search of an adequate model for the human metabolic syndrome, the metabolic characteristics of Wistar rats were analysed after being submitted to different protocols of high fructose ingestion. First, two adult rat groups (aged 90 d) were studied: a control group (C1; n 6) received regular rodent chow (Labina, Purina) and a fructose group (F1; n 6) was fed on regular rodent chow. Fructose was administered as a 10 % solution in drinking water. Second, two adult rat groups (aged 90 d) were evaluated: a control group (C2; n 6) was fed on a balanced diet (AIN-93G) and a fructose group (F2; n 6) was fed on a purified 60 % fructose diet. Finally, two young rat groups (aged 28 d) were analysed: a control group (C3; n 6) was fed on the AIN-93G diet and a fructose group (F3; n 6) was fed on a 60 % fructose diet. After 4-8 weeks, the animals were evaluated. Glucose tolerance, peripheral insulin sensitivity, blood lipid profile and body fat were analysed. In the fructose groups F2 and F3 glucose tolerance and insulin sensitivity were lower, while triacylglycerolaemia was higher than the respective controls C2 and C3 (P < 0.05). Blood total cholesterol, HDL and LDL as well as body fat showed change only in the second protocol. In conclusion, high fructose intake is more effective at producing the signs of the metabolic syndrome in adult than in young Wistar rats. Additionally, diet seems to be a more effective way of fructose administration than drinking water.
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(-)-Cubebin is a lignan extracted from the seeds of the pepper Piper cubeba, a commonly eaten spice with beneficial properties, including trypanocidal, anti-inflammatory, analgesic, anti-proliferative and leishmanicidal activities. Because of its therapeutic potential, we investigated the effects of (-)-cubebin on the cytotoxicity, cell proliferation kinetics, mutagenicity and expression of p38 MAP kinase and glutathione S-transferase a2 (GSTa2) using real-time RT-PCR in Rattus norvegicus hepatoma cells. We found that 280 μM (-)-cubebin was cytotoxic after 24, 48 and 72. h of exposure, but not mutagenic at 0.28 μM, 2.8 μM and 28 μM after 26. h. Similarly, exposure to 0.28 μM, 2.8 μM and 28 μM (-)-cubebin for 24, 48, 72 and 96. h did not alter the cell proliferation kinetics. Cells exposed to 28 μM (-)-cubebin for 24. h did not exhibit changes in p38 MAP kinase and GSTa2 expression, indicating that cellular changes were not induced by extracellular stimuli and that (-)-cubebin is likely not metabolized via this pathway. Our results suggest that high levels of (-)-cubebin should be consumed with caution due to the cytotoxic effect observed at the highest concentration. However, at lower concentrations, no cytotoxic, mutagenic or proliferative effects were observed, providing further evidence of the safety of consuming (-)-cubebin. © 2013 Elsevier Inc.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)