Eine Methode zur Extraktion der Verdickungsmittel in Fleischwaren

Zusammenfassung Eine rasche und einfache Extraktionsmethode für den Nachweis der Verdickungsmittel in Fleischwaren wird beschrieben. Das Prinzip beruht auf der Abtrennung der Polysaccharide durch Behandlung der Probe mit alkoholischer Kalilauge. Die abgetrennten Polysaccharide werden in heißem Wasser gelöst, mit Trifluoressigsäure hydrolysiert und die freigesetzten Monosaccharide als Aldonitrilacetate gaschromatographisch analysiert. Bei stärkehaltigen Proben ist eine Abtrennung der Stärke für eine Identifizierung erforderlich. Mit dieser Methode kann noch ein Gehalt von weniger als 0,1% Verdickungsmittel in Fleischwaren nachgewiesen werden.

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A method for the extraction of thickeners in meat products

Summary A rapid and simple method for the extraction of thickeners in meat products is described. The principle of this method is based on the separation of polysaccharides, which is achieved by treating the sample with an alcoholic solution of potassium hydroxide. The separated polysaccharides are dissolved in hot water and hydrolysed with trifluoroacetic acid. The resulting monosaccharides (as aldonitril acetates) are analysed by means of gas-liquid chromatography. When samples contain starch, the separation of starch is necessary for identification. Using the described method, less than 0.1 % of the thickeners can be detected in meat products.

     

Cell "vision": complementary factor of protein corona in nanotoxicology

Engineered nanoparticles are increasingly being considered for use as biosensors, imaging agents and drug delivery vehicles. Their versatility in design and applications make them an attractive proposition for new biological and biomedical approaches. Despite the remarkable speed of development in nanoscience, relatively little is known about the interaction of nanoscale objects with living systems. In a biological fluid, proteins associate with nanoparticles, and the amount and the presentation of the proteins on their surface could lead to a different in vivo response than an uncoated particle. Here, in addition to protein adsorption, we are going to introduce concept of cell "vision", which would be recognized as another crucial factor that should be considered for the safe design of any type of nanoparticles that will be used in specific biomedical applications. The impact of exactly the same nanoparticles on various cells is significantly different and could not be assumed for other cells; the possible mechanisms that justify this cellular response relate to the numerous detoxification strategies that any particular cell can utilize in response to nanoparticles. The uptake and defence mechanism could be considerably different according to the cell type. Thus, what the cell "sees", when it is faced with nanoparticles, is most likely dependent on the cell type.     

Adaptive robust boundary control of coupled bending‐torsional vibration of beams with only one axis of symmetry

In control design for vibration of beams in literature, the beam section is considered to have two axes of symmetry so that the bending and torsional vibrations are uncoupled; thus, the bending vibration is controlled independently without twisting the beam. However, if the cross section of a beam has only one axis of symmetry, the bending and torsional vibrations become coupled and the beam will undergo twisting in addition to bending. This paper addresses Lyapunov‐based boundary control of coupled bending‐torsional vibration of beams with only one axis of symmetry. The control strategy is based on applying a transverse force and a torque at the free end of the beam. The control design is directly based on the system partial differential equations (PDEs) so that spillover instabilities that are a result of model truncation are avoided. Three cases are investigated. Firstly, it is shown that when exogenous disturbances do not affect the beam, a linear boundary control law can exponentially stabilize the coupled bending‐torsional vibration. Secondly, a nonlinear robust boundary control is established that exponentially stabilizes the beam in the presence of boundary and spatially distributed disturbances. Thirdly, to rule out the need for prior knowledge of disturbances upper‐bound, the proposed robust control is redesigned to achieve an adaptive robust control that stabilizes the beam in the presence of disturbances with unknown upper‐bound. The efficacy of the proposed controls is illustrated by simulation results. Copyright © 2016 John Wiley & Sons, Ltd.     

An efficient method for the purification of arachidonic acid from fungal single-cell oil (ARASCO)

PUFA, such as arachidonic acid (AA), have several pharmaceutical applications. An efficient method was developed to obtain high-purity arachidonic acid (AA) from ARASCO, a single-cell oil from Martek (Columbia, MD). The method comprises three steps. In the first step, AA was enriched from saponified ARASCO oil by low-temperature solvent crystallization using a polar, aprotic solvent, which gave a FA fraction containing 75.7% AA with 97.3% yield. The second step involved enriching AA content via lipase-catalyzed selective esterification of FA with lauryl alcohol. When a mixture of 1 g FA/lauryl alcohol (2∶1 mol/mol), 50 mg Candida rugosa lipase, and 0.33 g water was incubated at 50°C for 24 h with stirring at 400 rpm, the AA content in the unesterified FA fraction was as much as 89.3%, with ca. 90% yield. Finally, a solvent extraction procedure, in which acetonitrile was the extracting solvent, was used to enrich AA from FA fraction dissolved in n-hexane. The best results were obtained when 2 g FA was dissolved in 80 mL hexane and extracted twice, each time with 20 mL acetonitrile at −20°C, by allowing 2 h storage. This step gave a FA fraction containing 95.3% AA with 81.2% yield. By using this three-step process the AA content in the saponified single-cell oil (ARASCO) was increased from 38.8 to 95.3% with a total yield of ca. 71%.     

Induction of cytosolic glutathione S-transferases from Atlantic eel (Anguilla Anguilla) after intraperitoneal treatment with polychlorinated biphenyls

Glutathione S-transferases (GST) are phase II biotransformation enzymes influenced by exposure to foreign compounds and are proposed as biomarkers of environmental pollution. The hepatic and renal cytosolic GST isoenzymes from juvenile Atlantic eels were isolated and partially characterized. In both organs, three different GST isoenzymes were purified using HPLC and the final subcellular purified fraction resulted in enzymatic subunits of approximately 24,500 Da. Total GST activity was significantly higher towards the substrate 1-chloro-2,4-dinitrobenzene (CDNB) than the ethacrynic acid (ETHA). Induction of isoenzymes of GST was studied after intraperitoneal treatment with a single dose (25 mg/kg bw) of a polychlorinated biphenyls mixture. In the hepatic cytosol, an inductory effect on the major enzymatic isoform was observed when comparing treated with control eels. This was directly related to statistically significant (P < 0.05) differences in total GST activity toward the CDNB between treated and control groups, with an increase of 33.6% of GST total activity measured in the last subcellular purified samples. In the kidney cytosol, PCB treatment did not affect GST activity. Significant differences were observed when analyzing the effect of PCB treatment on the main GST subunit height (retention time of 27 min). These results indicate that hepatic GST profiles could be considered as a good tool in environmental studies as specific biomarkers of contamination.     

Lipase‐catalyzed production of biodiesel from rice bran oil

Biodiesel has attracted considerable attention as an alternative fuel during the past decades. The main hurdle to the commercialization of biodiesel is the cost of the raw material. Use of an inexpensive raw material such as rice bran oil is an attractive option to lower the cost of biodiesel. Two commercially available immobilized lipases, Novozym 435 and IM 60, were employed as catalyst for the reaction of rice bran oil and methanol. Novozym 435 was found to be more effective in catalyzing the methanolysis of rice bran oil. Methanolysis of refined rice bran oil and fatty acids (derived from rice bran oil) catalyzed by Novozym 435 (5% based on oil weight) can reach a conversion of over 98% in 6 h and 1 h, respectively. Methanolysis of rice bran oil with a free fatty acid content higher than 18% resulted in lower conversions (<68%). A two‐step lipase‐catalyzed methanolysis of rice bran oil was developed for the efficient conversion of both free fatty acid and acylglycerides into fatty acid methyl ester. More than 98% conversion can be obtained in 4–6 h depending on the relative proportion of free fatty acid and acylglycerides in the rice bran oil. Inactivation of lipase by phospholipids and other minor components was observed during the methanolysis of crude rice bran oil. Simultaneous dewaxing/degumming proved to be efficient in removing phospholipids and other minor components that inhibit lipase activity from crude rice bran oil. Copyright © 2005 Society of Chemical Industry     

Uplink Resource Sharing and Power Management Scheme for an Underlay D2D Communication

Wireless Personal Communications - With the implementation of device-to-device (D2D) communication in primary cellular networks, there will be notable benefits such as increase in cellular...     

Probabilistic Hierarchical Model Using First Person Vision for Scenario Recognition

Wireless Personal Communications - Smart homes are becoming a growing need to prepare for a comfortable life style for the elderly and make things easy for the caretakers of the future. One...