Acrylamide formation and colour development in low-fat baked potato products as influenced by baking conditions and oil type

The objective of this study was to investigate the effect of oil type and oxidation status on acrylamide (AA) formation and colour development in potato products under domestic baking conditions. Sunflower, soybean and olive oil were used; the first one was thermally oxidized to obtain different oxidation status. A potato dough containing 10 % oil, potato powder, flour and water was shaped into thin discs and baked at 180 °C for different heating times. AA concentration, moisture content and surface colour were determined. Results obtained showed that neither the nature of lipids present, in terms of content of unsaturated fatty acids, nor the degree of fat oxidation influenced AA formation in low-fat baked potato products. Browning ratio higher than 45 % and moisture content lower than 17 % resulted in dark brown, almost burnt, products. Moreover, in those cases, no correlation could be found between those variables and AA content, since formation and degradation simultaneously occur. When the browning ratio ranged between 0 and 45 %, a good linear correlation with AA formation was observed, suggesting that the browning ratio may be considered as a reliable indicator of AA concentration. Finally, AA less than 1000 μg/kg, which is an indicative value that has been recently set for potato crisps by the European Commission, corresponds to a browning ratio of less than 8 % and moisture content more than 23.5 %.     

Measurement of the transient electrical and shaft torques in an induction motor drive by the indirect two-speed method

Contents This paper presents a new method, called Indirect Two-Speed Method (ITSM), for obtaining electrical and shaft torques in an induction motor drive by means of measuring the speeds of both lumped-inertia elements assigned to a second order model. The measuring is realized by using high-resolution digital tachometers (represented by incremental encoders), two frequency measurement systems based on the Double-Buffered Method, digitalfiltering of the raw speed data and numerical differentiation of the filtered speed data.

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Messung transienter Drehmomente eines Induktionsmotor-Antriebs mittels der Indirekten Zwei-Drehzahlen-Methode

Übersicht Im Beitrag wird ein neues Verfahren zur Ermittlung des elektrischen Moments und des Wellen-Drehmoments eines Induktionsmotor-Antriebs vorgestellt. Das als Indirekte Zwei-Drehzahlen-Methode (ITSM) bezeichnete Verfahren geht aus von einem mechanischen Modell zweiter Ordnung und mißt die Drehzahlen beider als konzentrierte Parameter betrachteten Drehmassen. Für die Durchführung werden hochauflösende digitale Tachometer eingesetzt. Die Frequenzmessung erfolgt durch ein Verfahren mit doppelter Pufferung, und es werden die Rohdaten nach digitaler Filterung numerisch differenziert.

     

Excess Molar Volumes and Viscosities of Mixtures of Diethylene Glycol Dibutyl Ether with Dialkyl Carbonates at 298.15, 308.15, and 318.15 K

Excess molar volumes,V ^E _m, and viscosities,, were measured as a function of composition for the binary mixtures of diethylene glycol dibutyl ether+dimethyl carbonate, +diethyl carbonate, and +propylene carbonate at temperatures of 298.15, 308.15, and 318.15 K and atmospheric pressure over the whole range of mixture compositions. From the experimental results, deviations in the viscosity,ln, and excess free energies of activation of viscous flow,G*^E, were calculated. The experimental results were correlated using the Redlich–Kister equation. The experimental and calculated quantities were used to analyze the mixing behavior of the components. Furthermore, activation enthalpies,H*, and entropies,S*, of viscous flow were evaluated and their variation with concentration is discussed.     

Is hepcidin‐25 a predictor of atherosclerosis in hemodialysis patients?

Atherosclerotic cardiovascular disease is an important cause of mortality and morbidity in hemodialysis patients. Iron accumulation in arterial wall macrophages is increased in atherosclerotic lesions. Hepcidin is a key hepatic hormone regulating iron balance. It inhibits iron release from macrophages and iron absorption from enterocytes by binding and inactivating the cellular iron exporter ferroportin. The aim of this study is to investigate the relation of hepcidin‐25, iron parameters, and atherosclerosis measured by carotid intima media thickness (CIMT) in hemodialysis patients. Eighty‐two hemodialysis patients were enrolled in this cross‐sectional study. Predialysis blood samples were centrifuged at 1500 g and 4°C for 10 minutes and stored at ?80°C for the measurement of hepcidin‐25. DRG hepcidin enzyme‐linked immunosorbent assay kit was used for the measurement of hepcidin‐25. Ultrasonographical B‐mode imaging of bilateral carotid arteries was performed with a high‐resolution real‐time ultrasonography (Mindray DC7). Mean age of the study population was 57.90 ± 16.08 years and 43.9% were men. Total study population was grouped into two according to median value of hepcidin‐25. There was no difference between groups with respect to age, dialysis vintage, and C‐reactive protein. CIMT was found to be statistically significantly higher in low hepcidin‐25 group. In correlation analysis, CIMT was found to be correlated with age (P < 0.01, R = 0.33) and hepcidin‐25 (P < 0.01, R = 0.46). In linear regression analysis, age (β = 0.31) and hepcidin‐25 (β = 0.44) were found to be the determinants of CIMT in hemodialysis patients. Our results implicate that hepcidin may take part in pathophysiology of atherosclerosis and cardiovascular disease in hemodialysis patients.     

Phosphotungstic Acid: An Efficient Catalyst for the Aqueous Phase Synthesis of Bis-(4-hydroxycoumarin-3-yl)methanes

In this present work, we report that phosphotungstic acid provides a simple, efficient and environmentally benign route is a two-component one-pot domino Knoevenagel-type condensation/Michael reaction between 4-coumarin derivative and an aldehyde in water as a solvent in shorter duration with high yields.      

Heterologous Expression and Partial Characterization of a Putative Opine Dehydrogenase from a Metagenomic Sequence of Desulfohalobium retbaense

The aim of this research was to prove the function of the putative opine dehydrogenase from Desulfohalobium retbaense and to characterize the enzyme in terms of functional and kinetic parameters. A putative opine dehydrogenase was identified from a metagenomic library by a sequence-based technique search of the metagenomic library, and afterward was successfully heterologously produced in Escherichia coli. In order to examine its potential for applications in the synthesis of secondary amines, first the substrate specificity of the enzyme towards different amino donors and amino acceptors was determined. The highest affinity was observed towards small amino acids, preferentially L-alanine, and when it comes to α-keto acids, pyruvate proved to be a preferential amino acceptor. The highest activity was observed at pH 6.5 in the absence of salts. The enzyme showed remarkable stability in a wide range of experimental conditions, such as broad pH stability (from 6.0–11.0 after 30 min incubation in buffers at a certain pH), stability in the presence of NaCl up to 3.0 M for 24 h, it retained 80 % of the initial activity after 1 h incubation at 45 °C, and 65 % of the initial activity after 24 h incubation in 30 % dimethyl sulfoxide.     

On the determination of characteristic temperatures in power oil transformers during transient states

Contents Under usual assumptions the equations describing thermal phenomena in a transformer are established. Without neglecting any substantially important factor, algorithms are developed for predicting the temperatures in critical spots in non-stationary states occurring either in practice or in load/time diagrams. This paper suggests the determinaton of conductances dependent on temperature and constant capacitances of equivalent thermal circuits of a transformer. They are based on a small number of experiments (as simple as possible) and on a parameter estimation procedure. In such a way the temperatures of transformer parts in different transient states can be determined by computer simulation established on equivalent circuits, so the operators in power and sub-stations will be able to load their transformers close to the permitted limit. It is felt that this paper may give a stimulation for a possible revision of IEC rules.

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Ermittlung charakteristischer Temperaturen von Leistungs-Öl-Transformatoren im nichtstationären Betrich

Übersicht Die Gleichungen des Temperaturverhaltens eines Transformators werden unter den üblichen Annahmen aufgestellt. Es werden Algorithmen entwickelt, welche die Vorausbestimmung der Temperatur an kritischen Stellen bei nichtstationärem Betrieb erlauben. Vorgeschlagen wird die Bestimmung der temperaturabhängigen und-unabhängigen Parameter auf Grund von wenigen und einfachen Messungen. Damit kann das Personal in Verteilerstationen in die Lage versetzt werden, mit Hilfe von PC's die Belastung der Transformatoren bis zu den zulässigen Grenztemperaturen auszudehnen. Die Autoren möchten damit einen Anstoß zu einer möglichen Überarbeitung von IEC-Vorschriften geben.

     

Effect of skin or muscle incisions or the loss of blood on serum leucogenenol level

It has been found that damage to a tissue of a rabbit or a rat, such as results from a skin incision or an incision through the skin and muscles into the abdominal cavity, is followed 24 hr later by a significant increase in the concentration of leucogenenol in the animal's serum. Likewise, loss of approximately one-quarter to one-half of the blood in the circulation of rabbits or rats causes an increase 24 hr later in the animals' serum leucogenenol concentration.     

Tuberculosis of the pyriform fossa--a rare entity

Tuberculosis of the pharynx is less common than tuberculosis of the larynx. We present a rare case of tuberculosis of the pyriform fossa which clinically masqueraded as a malignancy. Our patient showed a prompt improvement in symptoms after commencing antitubercular treatment.