Effect of phosphorylation of the maize starch on thermal generation of stable and short‐living radicals

Effect of hydrolysis, phosphorylation and treatment with high hydrostatic pressure on thermal generation of stable and short‐living radicals in maize starch was studied by X‐ray diffraction (XRD), electron paramagnetic resonance (EPR) spectroscopy, differential scanning calorimetry and polarized light microscopy. Phosphorus was introduced into maize starch as mono‐ and distarch phosphates. XRD indicated localization of phosphate groups in amorphous part of the granule whereas calorimetric data suggested some cross‐linking of the distarch phosphates. Stable and short‐living radicals with unpaired electron localized at carbon atom were generated in all investigated samples in the temperature range commonly used for processing food. The number of detected short‐living radicals, stabilized by a spin trap, is of two orders of magnitude greater than that of the stable radical species. Hydrolysis and phosphorylation strongly increase the number of stable radicals while pretreatment of the starch with high hydrostatic pressure diminishes their amount. The EPR spectra of stable radicals consist of two components, single line and another one with hyperfine structure, indicating interaction of unpaired electron with neighboring hydrogen atom. The EPR spectra of the spin trap adducts with short‐living radicals contain three components from species differing in their dynamic properties depending on localization in zones of various degree of crystallinity.     

Influence of cooking and microwave heating on microstructure and mechanical properties of transgenic potatoes

The transgenic potato clones of cultivar Irga with improved resistance to a necrotic strain of potato virus Y (PVY(N)) were subjected to heat treatment in order to determine their technological quality. The technological quality was determined on the basis of differences between mechanical properties of unmodified potato and transgenic clones during cooking and microwave heating. The compression test was applied in order to evaluate the mechanical resistance of raw, cooked and microwave-treated potatoes. Compression resistance was expressed by fracture stress F (kPa), fracture strain D (mm/mm), and Young modulus E (kPa). The differences in microstructure of potato tubers (unmodified and modified) were investigated using scanning electron microscopy (SEM). The observed differentiation in the mechanical properties of heat-treated potatoes was less connected with genetic modification but most of all with a kind of the process used. The heat processes caused a distinct decrease in mechanical resistance in all the examined tubers. However, the process of microwave heating resulted in more significant changes in mechanical properties of tubers than cooking. Deformation of parenchyma cells during cooking was directly connected with starch, gelatinisation and gel formation. Microwave heating affected significantly cellular water evaporation which resulted in intercellular failure, collapsing of cells, and limitation of starch gelatinisation.     

Elimination of resin acids by advanced oxidation processes and their impact on subsequent biodegradation

Wood pulping and paper production generate a considerable amount of wastewater, containing many pollutants among them resin and fatty acids. Resin acids contribute substantially to effluent toxicity and were identified to be detrimental to microorganisms of activated sludge and in particular to bacteria in anaerobic wastewater treatment system and other forms of aquatic life. The objective of the present study was to check the applicability of the ozone and advanced oxidation processes (AOPs) to eliminate resin acids from aqueous solutions and to determine the ozone dose required. Furthermore, an investigation of the influence of the oxidation methods on subsequent biological destruction of the byproducts was performed. Aqueous solution of the resin acids: abietic, dehydroabietic and isopimaric acids with different initial composition were subjected to ozonation or AOP processes at different ozone doses. After ozonation or advanced oxidation pretreatment the model solutions were biodegraded in aerated vessels containing activated sludge. During ozonation of the resin acids aqueous solutions the resin acids were almost eliminated, however the reduction of chemical oxygen demand (COD) was rather low. The ozone dose required to obtain reduction of resin acids >90% was in the range of 0.1-0.7mgO(3)/mgCOD, depending on the composition and concentration of model solutions. The toxicity of ozonated resin acids solutions decreased with increasing applied ozone dose up to about 0.3-0.5mgO(3)/mgCOD, thereafter increased. Ozonation and other AOP processes did not increase the rate of biodegradation of resin acids model solutions in aerated activated sludge systems compared to not pretreated solutions.     

Some estimates of the diffusion stress tensor and the diffusion energy for a binary mixture of water vapour and dry air

The diffusion stress tensor and the diffusion energy cause significant difficulties with their evaluation and physical interpretation. In this paper, an attempt of estimation of diffusion stress tensor and energy of diffusion in case of binary mixture of dry air and water vapour was made. There will be pointed out that their numerical value is negligible low in comparison with order of partial stress tensor and internal energy, respectively.     

The use of the MRI technique in the evaluation of water distribution in tumbled porcine muscle

The non-destructive magnetic resonance imaging (MRI) technique was used to study the spatial distribution of water in meat samples without and with brine and the influence of injection curing on water distribution in cured meat. Fresh non-treated porcine ham muscles (m. biceps femoris) were used; muscles injected with curing salt and subjected to half-time tumbling (3 h and 20 min) and full-time tumbling (6 h and 40 min) were studied. A "Lutetia" type 4 tumbler of French manufacture with a helicoidal paddle and a 2000 kg drum capacity was used. Histological examination of fresh non-treated muscles, after brine injection, and during and after the completion of tumbling demonstrated considerable differences. The use of MRI made it possible to estimate the effect of the tumbling procedure on the dynamics of brine migration and binding by muscle proteins. The spatial imaging of the proton density distribution confirmed that with longer meat tumbling times the binding of brine and its uniform distribution in the muscles increased.     

New Ammonium- and 1,2,4-Triazolium-Based Ionic Liquids for Wood Preservation

Biological activity of new potential wood preservatives—ammonium- and triazolium-based ionic liquids—was determined employing screening agar-plate, agar-block, and perlite-block methods. Experiments were carried out on Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.) wood. This study examined the effect of the ionic liquid structure on anti-fungal efficacy, depth of penetration, and fixation in wood. It was stated that the fungicidal value of new ammonium compounds depended, above all, upon the cation structure; for Coniophora puteana, it ranged from 2.7 kg m^?3 to 4.6 kg m^?3. These compounds effectively protected Scots pine wood against the action of mold fungi. Ammonium ionic liquids with a nitrite anion were characterized by strong fungitoxic properties, stronger than ammonium nitrates. The application in the amount of 15 g m^?2 caused an insignificant growth of mold fungi on the surface of Scots pine wood. For the mixture of 7.5% tebuconazole and 7.5% propiconazole dissolved in ionic liquids, the synergistic effect against mold fungi at the application of 15 g m^?2 was found. Dissolving tebuconazole in didecyldimethylammonium nitrate repeatedly lowered the fungicidal value against brown-rot fungi, as well as increased penetration of the ionic liquids in wood. This was associated with reduced viscosity of this ionic liquid caused by the addition of 1,2,4-triazole derivatives. Quaternary derivatives of 1,2,4-triazoles showed very high activity against blue stain and wood-decaying fungi. Additionally, most of the test compounds were well-fixed in Scots pine wood. The spectral study in infrared confirmed that nitrite, nitrate anions, and didecyldimethylammonium cation were retained in the treated wood.     

Thyristors and IGBTs with integrated self-protection functions

Recent activities in insulated gate bipolar transistor (IGBT) and thyristor development focus on the integration of protection functions in order to improve the reliability of the entire electronic system. It is shown how various protection functions can be integrated into symmetric and asymmetric light-triggered thyristors with a blocking capability up to 13 kV. Furthermore, different measures to provide IGBTs with an overvoltage protection are discussed and experimental results revealing the successful implementation of such a protection function are presented.     

Taste Preferences for Five Food-Associated Sugars in the Squirrel Monkey (Saimiri sciureus)

The taste preferences of six adult squirrel monkeys for sucrose, fructose, glucose, lactose, and maltose were assessed in two-solution choice tests of brief duration (5 min). In experiment 1 the monkeys were given the choice between all binary combinations of the saccharides presented in equimolar concentrations of 50, 100, 200, and 400 mM, respectively. Preferences for individual sugars were stable across the concentrations tested and indicate an order of relative effectiveness (sucrose > fructose > glucose ≥ maltose ≥ lactose), which is identical to the order of sensitivity found in this species and similar to findings on relative sweetness in man. In experiment 2 the squirrel monkeys were given the choice between a standard sucrose solution of 50 mM and ascending series of concentrations of the other saccharides in order to determine concentrations that were consumed in equal amounts compared to the standard. Solutions of 100 mM fructose, 300 mM glucose, and 200 mM lactose and maltose were found to be equally effective to the 50 mM sucrose, whereas other concentrations led to marked preferences for one of the alternatives. The finding of concentrations of equal effectiveness are consistent with findings on concentration-dependent loss of discrimination ability in man and support the hypothesis that for squirrel monkeys sucrose may indeed be indiscriminate from fructose, glucose, lactose and maltose when concentrations are suitably adjusted. The results suggest that squirrel monkeys and man share important features of sweet-taste perception.