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Physical methods of microalgal biomass pretreatment

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The prospect of depletion of natural energy resources on the Earth forces researchers to seek and explore new and alternative energy sources. Biomass is a composite resource that can be used in many ways leading to diversity of products. Therefore, microalgal biomass offers great potential. The main aim of this study is to find the best physical method of microalgal bio- mass pretreatment that guarantees efficient lipid extraction. These studies identifies biochemical composition of microalgal biomass as source for biodisel production. The influence of drying at dif- ferent temperatures and lyophilization was investigated. In addi- tion, wet and untreated biomass was examined. Cell disruption (sonication and microwave) techniques were used to improve lipid extraction from wet biomass. Additionally, two different extrac- tion methods were carried out to select the best method of crude oil extraction. The results of this study show that wet biomass after sonication is the most suitable for extraction. The fatty acid com- position of microalgal biomass includes linoleic acid (C18:2), palmitic acid (C16:0), oleic acid (C18:1), linolenic acid (C18:3), and stearic acid (C18:0), which play a key role in biodiesel production.
This study was aimed at determining lipid content, fatty acid composition and trans isomers content in fat extracted from cereals and cereal bars. Cereals and cereal bars were analyzed by gas chromatography. Analyses showed that they were characterized by a diversified content of fat and composition of particular groups of fatty acids (saturated SFA, monounsaturated MUFA and polyunsaturated PUFA). Only oat flakes turned out to be a good source of PUFA (38.83% of total fatty acids). The remaining products contained more SFA (mean: 45.12% and 47.73% in cereals and 63.31% in cereal bars) than PUFA (mean: 12.24% and 16.73% in cereals and 7.83% in cereal bars). Lipid of all examined products contained trans isomers of C18:1 and C18:2 acids. In lipids of cereals, the total content of these isomers did not exceed 0.5% of the total fatty acids. A higher content of these isomers was found in cereal bars (0.45–3.15%).
Peroxisome proliferator-activated receptors (PPAR`s) serve as lipid sensors and when activated modify gene expression of proteins highly involved in the regulation of fatty acid metabolism. Recently, the accumulation of lipids in liver was shown to be depended on the excessive protein-mediated transmembrane transport of long chain fatty acids (LCFAs). The aim of the present study was to determine the in vivo effects of PPAR and activation at two levels: 1) on the expression of fatty acid transporters, 2) on the content and fatty acids saturation status of lipids in rats liver. PPAR agonist (WY 14,643) treatment upregulated the liver expression of FAT/CD36 (+20%, p<0.05) and did not significantly affect the content of FABPpm and FATP-1. Accordingly there was a significant increase in the content of phospholipid (+12%, p<0.05), diacylglycerol (+65%, p<0.05) and triacylglycerol (+46%, p<0.05) fractions followed PPAR activation. In contrast, pioglitazone (PPAR agonist) had no effect on the content of fatty acid transporters (FAT/CD36, FABPpm and FATP-1) as well as the content of liver lipid fractions with the exception for triacylglycerols, which have been reduced significantly (-89%, p<0.05). These findings suggest that in vivo PPAR and PPAR activation exert different effects on both the expression of fatty acid transporters and lipid content in rat’s liver.
Variations in lipid, protein and carbohydrate contents of Enteromorpha spp. were examined over a seven-month period from April to October 1993. The samples were collected from seven sampling stations along the Gulf of Gdańsk coast. The lipid content was low and varied slightly from 3.47±1.76% of DW at Puck to 4.36±2.17% of DW at Rewa and Chałupy. The protein content varied from 9.42±4.62% of DW at Puck to 20.60±5.00% of DW at Jurata. At the remaining stations the values vary over a narrow range. The maximum protein contents were recorded at the beginning and end of the growing season. The level of carbohydrate was very high compared to that of lipid and protein and varied from 29.09±6.44% of DW at Osłonino to 39.81±11.15% of DW at Puck. Seasonal carbohydrate changes were noted at all sampling stations, the minimum occurring in spring and autumn and the maximum in summer.
Objectives: Obesity, insulin resistance and dyslipidemia are the most significant risk factors of non-alcoholic fatty liver disease (NAFLD) but the role of adipokines in the pathogenesis of this disease is not clear. Assessment of retinol binding protein (RBP-4) seems to be promising because data from animal and human studies suggest its role in the patomechanism of insulin resistance. Therefore, the aim of the study was to evaluate the serum levels of RBP-4 in children with NAFLD. Methods: Fasting serum level of RBP-4 was determined in 42 obese children with suspected liver disease and 20 lean controls. The degree of liver steatosis was graded in ultrasound according to Saverymuttu. The intrahepatic lipid content was assessed noninvasively in a semiquantitative fashion using 1HMR spectroscopy (1.5-T scanner with PRESS sequence). Results: Fatty liver was confirmed in 30 children by ultrasonography (16 of them had also increased alanine transaminase (ALT) activity). Serum concentrations of RBP-4 were significantly higher in obese children with NAFLD compared to controls. Significant correlations were found between RBP-4 level and ultrasonographic grade of liver steatosis, intrahepatic lipid content (1HMRS) and triglycerides level, while the serum level of RBP-4 was not significantly higher in children with advanced liver steatosis (grade 2-3, n = 11) compared to patients with mild steatosis (grade 1, n = 19). The ability of RBP-4 to differentiate children with advanced liver steatosis from those with mild steatosis was not significant. Conclusion: RBP-4 can be considered as a convenient serum marker of intrahepatic lipid content in obese children.
The content of total lipids and lipofuscins was determined in leaves of S. latifolium aerial-aquatic and terrestrial plants at the flowering and fruiting phases. There were no significant differences in the lipid total content between aerial-aquatic and terrestrial plants at the flowering phase. At the fruiting phase, the lipid content was lower in terrestrial plants. Lipofuscins, the so-called senescence pigments, were determined in plants of both ecotypes at the flowering phase, although visible symptoms of senescence were absent. At the fruiting phase, there was an accumulation of lipofuscins in aerial-aquatic and terrestrial plants that may be explained by progressive senescence. The lipofuscin content was higher in terrestrial plants at both phases of ontogenesis. We concluded that earlier and more intensive senescence is typical for terrestrial plants, which are in the conditions of chronic moderate water deficit on the riverside.
In a long-term study the effects of n-3 and n-6 polyunsaturated fatty acids on certain lipid metabolism parameters were compared. Male Wistar rats were divided into three experimental groups and were given diets with added studied fats. The diets contained 15% of energy from fats (7.5 g/100 g of diet) such as fish oil, sunflower oil and a mixture of butter and lard. At time intervals of 4 weeks, 12 weeks and 12 months the rats were decapitated and lipids were determined in their serum and tissues. In the aorta the axtent of fat deposits was measured plani- metrically. Fish oil was found to reduce most evidently the level of total cholesterol in serum and tissues. Sunflower oil in a lower degree decreased the accumulation of cholesterol in rat organism but increased the concentration of HDL-cholesterol. The atherogenic index in this group was lowest, and the extent of atheromatous lesions was least pronounced. The atherogenic effect of animal fats was confirmed.
In this study, Nusem and Beppo snack seed pumpkin cultivars were used to determine the effects of different plant activators on seed protein, lipid and fatty acids contents. In the context of study, plant activators consist of Crop-set (CR), EM1, ERS, Vitormone-Plus Drip (VIT), Bacillus subtilis (OSU 142), Bacillus megatorium (M3), Azospirillum sp. (SP 245), Spirulina platensis (SIP), Ecocompost (EKO), Camli Botanica liquid organic fertilizer (BOT) and Zincon (ZIN) were used as organic fertilizer. In the experiment, the plant activators were applied to the plants alone or in combination with each other and organic fertilizer. Two separate control groups which were organic and conventional (CONV.) fertilizer have been identified. As a result of the use of different plant activators, the highest protein content was obtained from CONV. application (35.50%), M3+SP 245 (33.09%) and M3 (33.04%); the highest lipid content was observed from SP 245+OG (45.90%), CR (44.48%) and SIP+OG (44.26%) applications. The use of different plant activators effected the fatty acid contents of seeds. Total 11 fatty acids were identified. Among the fatty acids, C16:0 (Palmitic acid), C18:0 (Stearic acid), C18:1 (Oleic acid) and C18:2 (Linoleic acid) were found dominant.
The influence of pepsin (EC 3.4.1.1) and trypsin (EC 3.4.4.4) action on the chemical composition of legume flours was the aim of this study. The level of proteins and lipids in hydrolysed flours was changed significantly. In comparison to the raw flours also fatty acid composition in treated flours was altered. In the lentil flours both trypsin and pepsin digestion conditions have decreased the level of unsaturated fatty acid. It is noteworthy that in all investigated, hydrolysed flours ratio linoleic: oleic fatty acid was significantly decreased in comparison to unhydrolysed flours (about 40%-pea; 60%-lentil). Our investigations were also focused on the potential implementations of IMAC method in the separation and purification of peptides. Generally, peptides separation profiles, performed on immobilized Zn (II), were dependent on the kind of flour and enzyme used in the hydrolysis process. In the lights of our results is clearly visible that investigated peptides had a weak affinity to the chelated metal ions. It is noteworthy, that in some cases the influences of chelating factor on separation profiles were noticeable.
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