RÉSUMÉ
Abstract Purpose: To investigate the fatty acid content of different fat sources and evaluate the effect of them on plasma and hepatic lipids and on the fatty acid profile of the brain tissue of Wistar rats. Methods: Thirty male albino Wistar rats received for 59 days, the following diets: diet added of margarine with low content of polyunsaturated fatty acids (PUFA); diet added of margarine with high content of PUFA; diet added of butter; diet added of hydrogenated vegetable fat; diet added of soybean oil. Fatty acid profile of the lipid sources, blood and hepatic lipids fractions and fatty acid profile of the brain tissue were determined. Results: Margarine consumption of provided different responses as to concentrations of blood and hepatic lipid fractions. Intake of butter and hydrogenated increased LDL-c/HDL-c ratio, being the steepest increase promoted by hydrogenated vegetable fat, which also raised LDL-c levels expressively. All fats used in the treatments reduced the cerebral concentration of docosahexaenoic acid when compared to soybean oil (control). Conclusion: The different fat sources commonly consumed by population provided different responses in vivo. This is particularly relevant considering the role of these lipids in the incidence and prevention of cardiovascular diseases.
Sujet(s)
Animaux , Mâle , Rats , Encéphale/métabolisme , Beurre/analyse , Acides gras insaturés/métabolisme , Lipides/sang , Foie/métabolisme , Margarine/analyse , Triglycéride/sang , Cholestérol/sang , Rat Wistar , Régime alimentaire , Métabolisme lipidique , Acides gras insaturés/composition chimique , Croissance , Hydrogénation , Foie/composition chimiqueRÉSUMÉ
Background: Lactobacillus sp. are probiotic microorganisms, and some of them are able to produce conjugated linoleic acid (CLA) via the bio-hydrogenation of linoleic acid (LA). Both CLA and LA are polyunsaturated fatty acids commonly used in the prevention and control of cardiovascular disease, high cholesterol, and cancer, among other ailments. The carbon source is one variable that can affect the growth and characteristics of these bacteria. Molecules called prebiotics are known to benefit human health by stimulating the growth and activity of probiotic bacteria present in the intestinal microflora. The aim of this study was to evaluate how different oligosaccharides affect the growth and fatty acid profile of Lactobacillus plantarum (NRRL - B4496). L. plantarum cultivation was performed in Man-Rogosa-Sharpe (MRS) medium, and the original carbon source (glucose) in this medium was partially or totally replaced by an oligosaccharide (isomalto-oligosaccharide (IMO) or gentio-oligosaccharide (GTO)). Then, the biomass concentration and fatty acid profile were determined using spectrophotometry and gas chromatography, respectively. Results: When 50% of the glucose in the MRS medium was replaced with IMO, the maximum growth was 2.6 g/L at 37ºC. Under the same culture conditions, the incorporation of GTO only produced 2 g/L of biomass. At 45ºC, the growth of the bacterial culture was lower than that observed at 37ºC, reaching only 0.4 g/L. When cultivated at 37ºC in a mixture of glucose and GTO (1:1), CLA (34%, c9t11) was obtained from cells of L. plantarum. However, when the cultivation was performed at 45ºC, CLA was not obtained. When IMO was used, differences in CLA content were not observed between L. plantarum cultivated with glucose or with IMO present; however, vaccenic acid was produced. Conclusions: Lactobacillus plantarum grow well when a mixture of IMO and glucose is used as the carbon source. However, this mixture does not improve the CLA content, most likely due to high enzymatic activity that promotes the conversion of CLA to vaccenic acid. Additionally, GTO is likely less readily metabolized by this strain. Thus, the enzymatic activity is likely lower and less CLA is converted to vaccenic acid, resulting in an accumulation of CLA.
Sujet(s)
Oligosaccharides/métabolisme , Lactobacillus plantarum/croissance et développement , Acides gras/analyse , Biomasse , Acide linoléique , Probiotiques , Milieux de culture , Prébiotiques , Hydrogénation , Chromatographie gazeuse-spectrométrie de masseRÉSUMÉ
O objetivo do presente trabalho consiste em uma revisão bibliográfica sobre os efeitos do consumo de ácidos graxos trans sobre a saúde do consumidor, servindo como veículo de alerta e informando sobre as quantidades diárias indicadas pelos órgãos competentes.
Sujet(s)
Humains , Acides gras trans/effets indésirables , Matières grasses alimentaires/métabolisme , Hydrogénation , Acides gras trans/administration et posologie , Étiquetage des aliments , Alimentation Industrielle , Faits NutritionnelsRÉSUMÉ
Objetivos: identificar a quantidade de gorduras totais, saturadas e trans descritas nos rótulos de biscoitos recheados e verificar se existe associação entre o preço e a quantidade de gorduras trans.Métodos: a amostra foi composta por 25 pacotes de biscoitos recheados de diferentes tipos e marcas, copiando-se de cada rótulo as informações necessárias. Para análise dos resultados foram efetuados cálculos de estatística descritiva, análise de variância e correlação de Spearmann.Resultados: os resultados apontam uma preocupação no consumo desses biscoitos, uma vez que a média dos biscoitos de duas marcas apresentaram valores próximos e que ultrapassam a recomendação máxima de gorduras trans (2,0 g) em uma porção média de 30 g (1,78 g e 2,05 g), com base em uma dieta de 2000 quilocalorias. Verificou-se também associação positiva entre preço e quantidade de gorduras trans (p<0,001) e associação inversa entre preço e quantidade de gordura saturada (p=0,003).Conclusões: quanto maior a quantidade de gorduras trans, menor a quantidade de gordura saturada e menor preço.Sugere-se uma revisão na legislação quanto à inserção da quantidade exata de gorduras trans no rótulo, uma vez que o consumo elevado dessas gorduras está associado a dislipidemias, um fator de risco para doença cardiovascular.
Aims: To identify the amount of total fat, saturated fat and trans fat described on the labels of filled cookies and to verify the association between price and trans fat content.Methods: The sample consisted of 25 packages of different types and brands of filled cookies, obtaining the necessary information from every label. Calculations of descriptive statistics, analysis of variance and correlation of Spearman were carried out.Results: The results call the attention for the consumption of these cookies, since the average of cookies of two brands presented values close and up to the daily recommendation of trans fat (2.0 g) in an average portion of 30 g (1.78 g and 2.05 g), based on a diet of 2000 kilocalories. We have also found a direct relation between price and trans fat value and reverse relation between price and saturated fat value.Conclusion: The more trans fat, the smaller price and quantity of saturate fat were found. We suggest a revision in the legislation regarding the inclusion of the exact amount of trans fat in the labels of every product, because high intakes of these fats are associated with dyslipidemia, which is a risk factor for cardiovascular disease.
Sujet(s)
Alimentation Industrielle , Biscuits , Cardiopathies , Composition Alimentaire , Économie de l'Alimentation , Graisses insaturées , Hydrogénation , Législation sur les aliments , Acides gras insaturésRÉSUMÉ
The solubility behavior of drugs remains one of the most challenging aspects in formulation development. Solid Dispersion (SD) has tremendous potential for improving drug solubility. Although praziquantel (PZQ) is the first drug of choice in the treatment of schistosomiasis, its poor solubility has restricted its delivery oral route. In spite of its poor solubility, PZQ is well absorbed in the gastrointestinal tract, but large doses are required to achieve adequate concentration at the target sites. The aim of this study was to improve the solubility and dissolution rate of PZQ and to evaluate its intestinal absorption. SDs were formulated with PEG-60 castor oil hydrogenated (CR-60) using a fusion and evaporation method. Pure PZQ and physical mixtures (PM) and PZQ-CR-60 (2:1; 1:1; 1:2 ratios) were compared as regards their solubility, dissolution and intestinal absorption. The experimental results demonstrated the improvement in the solubility, dissolution rate and intestinal absorption. In addition, the solubility behavior showed pH dependency and that the solubility of PZQ was slower in acidic medium than in neutral and basic mediums. The increase in PZQ solubility of the SD with the CR-60 could be attributed to several factors such as improved wettability, local solubilization, drug particle size reduction and crystalline or, interstitial solid solution reduction.
A solubilidade de fármacos ainda é um dos principais desafios no desenvolvimento de formulações farmacêuticas. As dispersões sólidas (DS) apresentam grande potencial para melhorar a solubilidade de fármacos. O praziquantel é o fármaco de primeira escolha no tratamento da esquistossomose, contudo a baixa solubilidade em água restringe seu uso à administração pela via oral. Apesar da baixa solubilidade, o PZQ é bem absorvido através do trato gastrintestinal, mas doses orais elevadas são requeridas para garantir concentrações suficientes de fármaco para o tecido alvo. O objetivo deste estudo foi melhorar a solubilidade, a dissolução e avaliar a absorção do PZQ. As DS foram formuladas com óleo de castor hidrogenado - PEG 60 (CR-60), pelo uso dos métodos de fusão e evaporação do solvente. PZQ puro, mistura física (MF) e DS de CR-60-PZQ (1:2; 1:1; 2:1) foram comparados quanto à solubilidade, dissolução e absorção intestinal. Os resultados experimentais mostraram aumento na solubilidade, na taxa de dissolução e na absorção intestinal do PZQ nas DS. A solubilidade do PZQ foi maior em meio ácido, mostrando uma dependência do pH. O aumento na solubilidade do PZQ nas DS com CR-60 foi atribuída a fatores como aumento da molhabilidade, solubilização local, redução granulométrica e redução da cristalinidade ou, ainda, a ocorrência de uma solução sólida intersticial.
Sujet(s)
Phénomènes chimiques/statistiques et données numériques , Dissolution/méthodes , Émulsifiants , Huile de ricin/analyse , Praziquantel/pharmacologie , Hydrogénation , Interprétation statistique de donnéesRÉSUMÉ
To improve mass transfer and enhance the yield for C(1,2) biodehydrogenation of steroid 11beta-hydroxyl medroxyprogesterone, we carried out the dehydrogenation reaction of 11beta-hydroxyl medroxyprogesterone in an oil-in-water (O/W) microemulsion by Arthrobacter simplex UR016. We studied the effects of system composition, dehydrogenation temperature and substrate concentration on microbial transformation. We formulated a suitable O/W microemulsion system with Arthrobacter simplex UR016 culture broth as aqueous phase, 10 g/L of edible oil as oil phase, 4 g/L of Tween-O80 and 7% (V/V) alcohol as surfactant and cosurfactant. The optimal dehydrogenation temperature was 33 degrees C. The results showed that in Tween-80/alcohol/edible oil/water microemulsion system, the hydrophobic steroid was solubilised and diffused effectively, with the maximum conversion rate of 88.6% at 46 h under 4 g/L substrate concentration, an increase of 66.2% compared to that in aqueous system. The C(1,2) biodehydrogenation of 11beta-hydroxyl medroxyprogesterone is more efficient in water-edible oil microemulsion system than in aqueous system.
Sujet(s)
Arthrobacter , Métabolisme , Biotransformation , Émulsions , Hydrogénation , Médroxyprogestérone , Chimie , MétabolismeRÉSUMÉ
It has been observed that foods with similar amount of starch can generate different glycemic responses. The evidence of a direct link between saturated fat consumption and an increased risk of cardiovascular diseases has led consumers to consider oils derived from vegetables, and industrial products derived from them, as healthier substitutes than animal fats. During the technological manipulation of vegetable oils, in order to transform them into more stable products it is applied the process of hydrogenation. The main side effect of this process is the formation of geometric and positional isomers of the unsaturated fatty acids, primary trans isomers of fatty acids (TFA). Dietary TFA consumption has a biological and industrial origin; the latter found in margarine, shortening, home and industrial cooking oil, bakery goods, and the wide range of' snack foods. Substantial TFA amounts come from the so called "invisible fats", the raw material used to manufacture more complex foods. The current wisdom is that TFA have an adverse effect on cardiovascular health, and its consumption poses a potential risk for increasing the incidence of heart disease.
La evidencia sobre una relación directa entre el consumo de grasas saturadas y el riesgo de enfermedad cardiovascular ha llevado a que los consumidores consideren a los aceites vegetales y a los productos industriales que derivan de ellos, como productos más saludables y sustitutos de las grasas animales. Durante el procesamiento tecnológico de los aceites vegetales, con la finalidad de transformarlos en productos más estables, se aplica el proceso de hidrogenación. El principal efecto lateral de este proceso es la formación de isómeros geométricos y posicionales de los ácidos grasos insaturados, principalmente de isómeros trans (AGT). Los AGT dietarios tienen origen biológico y tecnológico; estos últimos se encuentran en margarinas y mantecas, en aceites de uso doméstico e industrial, en productos de horneo, y en una gran variedad de alimentos del tipo bocadillos. Las grasas utilizadas para la manufactura industrial de alimentos (grasa "invisible") contienen elevadas cantidades de AGT. La visión actual es que los AGT tienen efectos adversos en la salud cardiovascular y que su consumo constituye un riesgo potencial de incrementarlas enfermedades cardíacas.
Sujet(s)
Humains , Acides gras insaturés/métabolisme , Acides gras insaturés/composition chimique , Régime alimentaire , Acides gras trans/métabolisme , Acides gras trans/composition chimique , Cholestérol/métabolisme , Maladies cardiovasculaires/étiologie , Manipulation des aliments , Technologie alimentaire , Hydrogénation , Isomérie , Lipoprotéines/métabolismeRÉSUMÉ
In this paper, we address the preparation of the EPC and HEPC sterically stabilized doxorubicin liposomes and report the data collected from further studies on pharmacokinetics in blood for choosing a better carrier in delivering the drugs. The pharmacokinetics of EPC and HEPC sterically stabilized liposomes (EPC-SSL, and HEPC-SSL) in Wistar rats were investigated by HPLC. The results showed that the mean residence time of HEPC-SSL in blood is 23.3 h, while that of EPC-SSL is 12.0 h. In conclusion, HEPC-SSL is a better carrier in delivering the drugs to the extravascular sites when compared with EPC-SSL.
Sujet(s)
Animaux , Rats , Antibiotiques antinéoplasiques , Pharmacocinétique , Préparations à action retardée , Pharmacocinétique , Doxorubicine , Pharmacocinétique , Vecteurs de médicaments , Chimie , Hydrogénation , Liposomes , Phosphatidylcholines , Chimie , PharmacologieRÉSUMÉ
There is a mounting concern about the intake of foods containing trans fatty acids (TFA) due to their deleterious effects on human health, mainly on the cardiovascular system. In this way, it is important to consider the processes that form TFA in foods, and the alternatives to minimize them. Among the processes that result in the formation of TFA, the hydrogenation of vegetable oils stands out for its impact on the diet of people living in industrialized countries. Other processes such as edible oil refining, meat irradiation, food frying, and biohydrogenation also contribute to increase the daily intake of TFA.
Existe uma crescente preocupação em relação a ingestão elevada de ácidos graxos trans (AGT), devido aos seus efeitos desfavoráveis à saúde, principalmente sobre o sistema cardiovascular. Assim, é importante considerar os processos queoriginam os AGT nos alimentos, e as alternativas para minimizar a sua formação. Entre os processos que resultam na produção de AGT, a hidrogenação de óleos vegetais tem recebido o maior destaque por seu impacto na dieta de pessoas que vivem em países industrializados. Outros processos, como o refino de óleos vegetais, a irradiação de carnes, o preparo de alimentos fritos e a bio-hidrogenação, também contribuem para aumentar a ingestão diária de AGT.
Sujet(s)
Humains , Manipulation des aliments/méthodes , Huiles végétales/métabolisme , Acides gras trans/métabolisme , Hydrogénation , Acides gras trans/effets indésirablesRÉSUMÉ
In order to look for lower toxic and strongly active compounds, the structure of sesquiterpene lactones from Elephantopus scaber was modified. Deoxyelephantopin and scabertopin were isolated from the whole plant of Elephantopus scaber and hydrogenated and epoxidated. Five sesquiterpenoide derivatives were prepared and their structures were identified by IR, NMR and MS spectra analysis. Four sesquiterpenoides are new compounds. Part of the compounds show definite antitumor activity.
Sujet(s)
Humains , Antinéoplasiques d'origine végétale , Chimie , Pharmacologie , Asteraceae , Chimie , Cellules HeLa , Hydrogénation , Lactones , Chimie , Pharmacologie , Structure moléculaire , Plantes médicinales , Chimie , Sesquiterpènes , Chimie , Pharmacologie , Terpènes , Chimie , PharmacologieRÉSUMÉ
PURPOSE: The estrogen receptor (ER), which is over-expressed in ER-positive breast tumors, has been imaged by positron emission tomography (PET) using [18F] labeled estrogen ligands, especially [18F]FES. However, [18F] has relatively short-lived half-life (t1/2=1.8 h) and the labeling yield of radio-fluorination is usually low compared with 64Cu (t1/2=12.7 h). 1,4,7,10-tetraazacyclododecane (cyclen) is used to form stable metal complexes with copper, indium, gallium, and gadolinium. With these in mind, we prepared cyclen-based Cu complexes which mimic estradiol in aspect of two hydroxyl groups. MATERIALS AND METHODS: 1,7-Protected cyclen, 1,7-bis (benzyloxycarbonyl)-cyclen was synthesized according to the reported procedure. After introducing two 4-benzyloxybenzyl groups at 4,10-positions, the benzyloxycarbonyl and benzyl groups were removed at the same time by hydrogenation on Pd/C to give 1,7-bis(4-hydroxybenzyl)-1,4,7,10-tetraazacyclododecane (1). RESULTS: The prepared ligand 1 was fully characterized by 1H, 13C NMR, and mass spectrometer. The synthesized ligand was reacted with copper chloride and copper perchlorate to give copper complexes [Cu(1)]2+2(ClO4-) and [Cu(1)Cl]+Cl- which were confirmed by high-resolution mass (FAB). CONCLUSION: We successfully synthesized a cyclen derivative of which two phenol groups are located on trans position of N-atoms. And, two Cu(II) complexes of +2 and +1 overall charge, were prepared as a potential PET tracers for ER imaging.
Sujet(s)
Tumeurs du sein , Complexes de coordination , Cuivre , Oestradiol , Oestrogènes , Gadolinium , Gallium , Période , Hydrogène , Hydrogénation , Indium , Ligands , Phénol , Tomographie par émission de positonsRÉSUMÉ
Os ácidos graxos trans estão presentes em óleos ou gorduras naturais que sofreram o processo de hidrogenação, e esse processo consiste na adição de hidrogênio gasoso às duplas ligações dos ácidos graxos insaturados dos óleos ou gorduras naturais, produzindo saturação total ou parcial. Estudos científicos têm demonstrado o papel dos ácidos graxos trans, presentes na dieta e sua correlação com doenças cardiovasculares e crônico-degenerativas. No entanto, este tipo de gordura é extremamente maléfica ao organismo e tem tido seu consumo aumentado nos últimos anos, pois os ácidos graxos trans, estão presente em carnes vermelhas, manteiga, biscoitos doces, frituras, maionese, pães, bolos, dentre outros produtos de consumo diário na vida das pessoas. A redução do consumo de ácidos graxos trans em nosso país, deve envolver seus malefícios à população e a realização de mais estudos, que visem determinar o seu real conteúdo nos alimentos, além de estimar os níveis de ingestão diária.
Sujet(s)
Maladies cardiovasculaires , Matières grasses alimentaires/effets indésirables , Acides gras trans , Hydrogénation , Facteurs de risqueRÉSUMÉ
Óleo da castanha do Pará (Bertholletia excelsa), extraído por prensagem das sementes a frio, foi submetido às modificações de fracionamento, hidrogenação, interesterificação e misturas com as gorduras obtidas na hidrogenação. Na hidrogenação o óleo foi submetido a três reações em reator Parr de 1 L, catalisador de níquel (Pricatt 9920-06 - Unichema), e sob as seguintes condições: 175ºC, 3 atm, 60 min (GH1), 150ºC, 1 atm, 30 min (GH2) e 125ºC, 1 atm, 30 min (GH3). O teor de acido esteárico aumentou de 11,6 por cento (óleo original) a 56,7 por cento, 16,3 por cento e 15,3 por cento em GH1, GH2 e GH3, respectivamente. O ácido oléico, representando 34,5 por cento no óleo original descresceu em GH1 a 25,9 por cento e aumentou em GH2 e GH3 a 59,9 por cento e 53,8 por cento, respectivamente...
Sujet(s)
Acide oléique/analyse , Acides stéariques/analyse , Acides gras/analyse , Mélanges Alimentaires , Technologie alimentaire , Acylglycerol lipase/analyse , Huiles végétales/analyse , Fractionnement chimique , Hydrogénation , Phénomènes chimiquesRÉSUMÉ
La hidrogenación biológica de los rumiantes o la industrial producen isomerización de los ácidos grasos que componen la grasa, pudiéndose formar isómeros trans. Se ha postulado que una dieta alta de estos isómeros puede ser un riesgo para la salud, aunque no se conocen con certeza las consecuencias de su ingesta. Existen numerosos estudios epidemiológicos que asocian el consumo de ácidos grasos trans con riesgos como: aumento del colesterol LDL y disminución del HDL, aumento del riesgo de enfermedad coronaria, aumento del la Lp(a), aumento de la probabilidad de padecer cáncer de mama y de colon, la interferencia en el metabolismo de los ácidos grasos esenciales y también se cree que pueden comprometer el desarrollo fetal e infantil. En varios países se ha disminuído el consumo de isómeros trans mediante la reducción del contenido de los mismos en margarinas (una de las principales fuentes de trans) pero no así en productos alimenticios industriales. La ingesta estimada de AG trans para EE.UU. es de 5,3 - 8,1 g/día y en Europa de 1,4 - 5,4 g/día. Hasta nuestro conocimiento, en la Argentina todavía no hay datos de ingesta de AG trans como así tampoco información sobre el contenido de éstos en los alimentos. En este trabajo se incluyen los resultados de análisis realizados en algunos alimentos potenciales fuentes de AG trans y datos sobre su contenido en leche materna como reflejo de su consumo. Los valores más altos fueron hallados en las margarinas (19 a 9,5 g por ciento), mientras que papas fritas de "fast food" contenían 6,5 g por ciento y algunos panificados con 0,1 a 3,6 g por ciento. En la leche materna se halló que un 2,5 g por ciento del total de ácidos grasos se hallaban en forma de isómeros trans
Sujet(s)
Humains , Animaux , Grossesse , Nouveau-né , Acides gras/analyse , Acides gras/effets indésirables , Matières grasses alimentaires/effets indésirables , Lait humain , Huiles végétales/analyse , Tumeurs du sein/induit chimiquement , Développement de l'enfant , Tumeurs du côlon/induit chimiquement , Maladie coronarienne/diétothérapie , Matières grasses alimentaires/analyse , Développement foetal , Hydrogénation , Isomérie , Margarine/effets indésirables , Margarine/analyse , Table de la Composition AlimentaireRÉSUMÉ
Aborda o tema ácidos graxos trâns-isômeros, enfocando alguns aspectos tecnológicos da hidrogenaçäo das gorduras vegetais e suas implicaçöes do ponto de vista nutricional, sugerindo a necessidade de novos estudos e pesquisas para investigar o teor destes compostos nos alimentos, o grau de ingestäo dos mesmos pela populaçäo e propor a inclusäo destes dados em rótulos de alimentos, como forma de veicular informaçöes importantes e de caráter preventivo e educativo para o consumidor.
Sujet(s)
Acides gras insaturés , Étiquetage des aliments/normes , Hydrogénation , Matières grasses alimentairesRÉSUMÉ
In Pakistan, hydrogenated oils [commonly called ghee] are the predominant source of dietary fats. Several metabolic and epidemiological studies have contributed to concern about the adverse effects of the transisomers of fatty acids which are formed when liquid, vegetable oils are partially hydrogenated to form ghee, margarine, etc in Pakistan, palm oil is the main precursor for hydrogenation, to get semisolid form or ghee. Polyunsaturated fatty acid contents of palm oil are lower than those of other popular edible oils derived from soyabean, sunflower and corn. Physicians encourage vegetable oils rich in polyunsaturated fatty acids and discourage the use of animal fats because of their high contents of saturated fats and cholesterol. By many people the use of ghee and margarine derived from cholesterol free vegetable oils, is regarded as a healthy eating behaviour, as opposed to butter fat. These partially hydrogenated vegetable oils with high contents of the trans fatty acids, in fact, are even greater health hazards than the cholesterol containing dairy fat
Sujet(s)
Huiles végétales/effets indésirables , Maladie coronarienne/étiologie , HydrogénationRÉSUMÉ
Se describe la utilización de tamices moleculares en la reacción, de hidrogenación de CO. Esta reacción, conocida también como síntesis FischerTropsch, produce una gran cantidad de compuestos principalmente alcanos lineales, alkenos y compuestos oxigenados, debido a que la misma sigue un proceso de oligomerización reductiva de monóxido de carbono o de sus derivados superficiales. El reto más importante de éste proceso continúa siendo el control de la distribución de productos. En el presente trabajo se describe como mediante el uso de diferentes tamices moleculares tales como zeolitas, arcillas pilareadas y aluminofosfatos, es posible minimizarla formación de hidrocarburos con un número de átomos de carbono superior al rango de gasolinas, mejorando de esta forma la selectividad de la reacción hacia productos deseados
Sujet(s)
HydrogénationRÉSUMÉ
O mercado brasilero é constituído de uma amplavariedade de produtos hidrogenados para uso gerale e específico, principalmente a nível industrial. No presente trabalho foram estudadas 19 amostras de gorduras hidrogenadas para uso específico (shortenings) e a fraçao lipídica de 14 amostras de margarinas e 9 cremes vegetais. Nas amostras citadas foram realizadas determinaçoes de índice de iodo, ponto de amolecimento, teor de isomeros trans, teor de gordura sólida e composiçao em ácidos graxos. O teor de isomeros trans na maioria das amostras foi elevado, em torno de 30 por ciento, variado entre O e 62 por ciento. Propiedades termicas como o teor de gordura sólida e ponto de amolecimento apresentaram pouca semelhança entre os 3 grupos de amostras e entre as amostras. Aparentemente quase todas as gorduras comercializadas no Brasil sao produzidas a partir de misturas de óleos de soja com diferentes graus de hidrogenaçao
Sujet(s)
Acides gras insaturés/composition chimique , Acides gras/composition chimique , Acides gras/composition chimique , Hydrogénation , Iode/analyse , BrésilSujet(s)
Animaux , Gangliosides/synthèse chimique , Humains , Hydrogénation , Hydrolyse , Photochimie , Radio-isotopesRÉSUMÉ
La producción nacional de aceite de pescado ha aumentado en forma sensible en los últimos cuatro años, en virtud de la expansión de las industrias de "reducción" (harina de pescado). Sin embargo, esta producción se destina, casi en su totalidad, a usos industriales (lubricantes, curtiduría, etc.). Algunos países como Japón, canadá y Perú han venido utilizando el aceite de pescado de diversas especies para consumo humano. En vista d elo expuesto, los objetivos del presente trabajo fueron: primeiro, establecer las condiciones experimentales para obtener una grasa hidrogenada de pescado y segundo, formular mezclas de ésta con grasas vegetales para su utilización en la industria alimentaria. La metodología comprende lo siguiente: 1) Caracterización del aceite crudo de pescado mediante análissi físicos y químicos; 2) adaptación del proceso de refinación de aceites vegetables al aceite de pescado y 3) elaboración de mezcladas de grasa de pescado con grasas vegetables. Se obtuvo una grasa hidrogenada de pescado con punto de fusión 36-C, índice de yodo 80; punto de humeo 248-C, color lovibond, 20 amarillo y 1.3 rojo. A partir de los resultados de las pruebas sensoriales, se estableció la posibilidad de utilizar una grasa vegetal "extendida" con grasa de pescado en un 30% para frituras, y en un 50% para productos de panificación