Changes in Particle Size Distribution of Bran and Flour Obtained from Vacuum Impregnated and Infra-red Heated Wheat Grain

This study aims to provide comprehensive information on the process of vacuum impregnation of wheat grains. Vacuum impregnation, saturating materials with additional liquid components, is a well-known process originally developed to ensure leak tightness or reduce the porosity of various materials. We describe its potential uses in the food processing industry relating to the impregnation of grains and leguminous plant seeds. The objective of the study was to determine the influence of impregnation and infrared heating of wheat grains on flour efficiency, moisture content and particle size distribution in the resulting flour and bran. The experimental material comprised three varieties of wheat. The results showed that the method of preparing the wheat grains for milling combined with impregnation had a significant impact on the particle size distribution of bran but not on the particle size distribution of flour. A more complete view of the process characteristics requires further investigation of factors related to the structural and textural properties of the impregnated material, factors which are highly varied in the case of food materials and food products.     

Optical anisotropy,molecular orientations,and internal stresses in thin sulfonated poly(ether ether ketone) films

The thickness, the refractive index, and the optical anisotropy of thin sulfonated poly(ether ether ketone) films, prepared by spin-coating or solvent deposition, have been investigated with spectroscopic ellipsometry. For not too high polymer concentrations (≤5 wt%) and not too low spin speeds (≥2000 rpm), the thicknesses of the films agree well with the scaling predicted by the model of Meyerhofer, when methanol or ethanol are used as solvent. The films exhibit uniaxial optical anisotropy with a higher in-plane refractive index, indicating a preferred orientation of the polymer chains in this in-plane direction. The radial shear forces that occur during the spin-coating process do not affect the refractive index and the extent of anisotropy. The anisotropy is due to internal stresses within the thin confined polymer film that are associated with the preferred orientations of the polymer chains. The internal stresses are reduced in the presence of a plasticizer, such as water or an organic solvent, and increase to their original value upon removal of such a plasticizer.     

Sources, properties and suitability of new thermostable enzymes in food processing

Investigations concerning recombinant a-amylases from Pyrococcus woesei and thermostable a-glucosidase from Thermus thermophilus indicate their suitability for starch processing. Furthermore, the study of recombinant ss-galactosidase from Pyrococcus woesei suitable for purpose of low lactose milk and whey production are also presented. The activity of this enzyme in a wide pH range of 4.3-6.6 and high thermostability suggests that it can be used for processing of dairy products at temperatures which restrict microbial growth during a long operating time of continuous-flow reactor with an immobilized enzyme system. Preparation of recombinant a-amylase and ss-galactosidase was facilitated by cloning and expression of genes from Pyrococcus woesei in Escherichia coli host. Satisfactory level of recombinant enzymes purification was achieved by thermal precipitation of native proteins originated from Escherichia coli. The obtained a-amylase has maximal activity at pH 5.6 and 93 degrees C. The half-life of this preparation (pH 5.6) at 90 degrees C and 110 degrees C was 11 h and 3.5 h, respectively, and retained 24% of residual activity following incubation for 2 h at 120 degrees C. An advantageous attribute of recombinant a -amylase is independence of its activity and stability on calcium salt. a-Glucosidase from Thermus thermophilus also not require metal ions for stability and retained about 80% of maximal activity at pH range 5.8-6.9. Thus, this enzyme can be used together with recombinant a-amylase.     

Electron Transfer Photoinitiating Systems. The Effect of the Co‐Initiator Structure on the Photoinitiation Ability of a Photoredox Pair Containing Neutral Hemicyanine Dyes as Sensitizers

Summary: The photoinitiation ability of photoredox pairs composed of a neutral hemicyanine dye and different co‐initiators for the free radical polymerization of 2‐ethyl‐2‐(hydroxymethyl)propane‐1,3‐diol triacrylate is investigated. p‐(N,N‐dimethylaminostyryl)benzthiazole, p‐(N,N‐dimethylaminostyryl)benzoxazole, p‐(N,N‐dimethylaminostyryl)α‐naphthiazole are tested as dyes, and, as co‐initiators, an aromatic amino‐acid, an aromatic thio‐ and oxycarboxylic acid, and alkyltriphenylborate are applied as electron donors. N,N′‐dialkoxybipyridinium salts are used as ground‐state electron acceptors. The experimental results show that the photoinitiating ability of the tested photoredox pairs are controlled by both the driving force of the electron transfer process between an electron donor and an electron acceptor and the reactivity of the free radical that results from the secondary reactions occurring after the photoinduced electron transfer process. The greatest photoinitiation ability of free radical polymerization is observed when the tested dyes are applied as electron donors in their singlet excited states in combination with N,N′‐dialkoxybipyridinium salts acting as ground‐state electron acceptors.

Schematic of the investigated photoinitiation systems.     

TiO2 Nanoparticles with High Photocatalytic Activity Under Visible Light

TiO₂ nanoparticles (C-TNT) with high visible light activity were obtained by carbonization of titania nanotubes (TNT) in an ethanol atmosphere under elevated pressure at 180 and 220 °C. New material was characterised by means of UV–Vis/DR, FTIR/DRS, TEM, and XRD. The photocatalytic activity was tested during monoazo dye decomposition under artificial solar light irradiation. Modified photocatalyst (220 °C, 4 h) had higher photocatalytic activity than both the pristine and commercial P25 catalysts.     

Multi-walled carbon nanotube-supported tungsten oxide-containing multifunctional hybrid electrocatalytic system for oxygen reduction in acid medium

Combination of multi-walled carbon nanotubes, cobalt porphyrin and tungsten oxide in the film (deposited onto glassy carbon electrode substrate) produces an electrocatalytic system capable of effective reduction of oxygen in such acid medium as 0.5 mol dm⁻³ H₂SO₄.Co-existence of cobalt porphyrin and tungsten oxide, together with dispersed carbon nanotubes, leads to the enhancement effect evident from some positive shift in the oxygen reduction voltammetric potential and the significant increase of voltammetric currents (relative to those characteristic of the system free of carbon nanotubes and WO₃). The multi-component electrocatalytic film has also exhibited relatively higher activity towards reduction of hydrogen peroxide. It is reasonable to expect that the reduction of oxygen is initiated at the cobalt porphyrin redox centers, and the undesirable hydrogen peroxide intermediate is further reduced at the tungsten oxide support. An important function of carbon nanotubes is to improve transport of electrons within the electrocatalytic multi-component film.     

BiNbO4-Based Glass–Ceramic Composites for Microwave Applications

The effect of a bespoke glass sintering aid, 0.3Bi₂O₃–0.3Nb₂O₅–0.3B₂O₃–0.1SiO₂ (BN1), developed from the base ceramic composition, BiNbO₄ (BN), on the sinterability, microstructure, and microwave (MW) dielectric properties of BN ceramics has been investigated. Densities >97% theoretical could be achieved at 1020°C for samples with up to 15% BN1 additions. The resulting microstructure was composed of BN laths surrounded by a residual glass phase that contained small fibrous crystals. Some evidence of dissolution of BN crystals was observed. Optimum properties were exhibited for samples with 15 wt% of glass addition sintered for 4 h at 1020°C with a relative permittivity ɛ_r=38, a MW quality factor Q × f ₀=17 353 at 5.6 GHz, and a temperature coefficient of resonant frequency τ_f=−10 ppm/°C. The high Q × f ₀, ɛ_r, and low τ_f, coupled with a relatively low sintering temperature, suggest that the use of bespoke glass sintering aids of this type may have great potential for the fabrication of MW ceramics.     

Application of different analytical methods used in the study of the cross‐linking of resins in intermediate‐product used in manufacturing of abrasive articles

Determining the degree of the crosslinking of resins in intermediate‐product used in the manufacturing of abrasive articles is difficult and complicated because of the presence of different components in the material. The abrasive articles consist of abrasive (e.g., fused alumina), filler (e.g., potassium fluoroborate–KBF₄, pyrite–FeS₂), wetting agent (e.g., resol), and binder (e.g., novolak). Proper hardening of intermediate‐product is a very important stage during production of abrasive tools. The hardening process depends on crosslinking of resins. Following were used to study crosslinking of resins: IGC, washing away method, NMR broad line, DSC, and FTIR methods. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Determination of 4‐ethylcatechol in a Merlot wine using sensory evaluation and the electronic tongue

The objective of this study was to determine the influence of 4‐ethylcatechol (4‐EC) on the sensory profile of Brettanomyces‐contaminated Merlot wine and evaluate electronic tongue discrimination. Using sensory evaluation panels, the consumer detection threshold (DT) and the consumer rejection threshold (CRT) of 4‐EC were determined in Merlot containing 493, 714, 1035 and 1500 μg L^?1 4‐EC. The DT of 4‐EC in Merlot was 823 μg L^?1, while the CRT was 1323 μg L^?1. The electronic tongue discriminated index (DI = 82%) among the samples, with hierarchical clustering showing a clear distinction between the control sample and the spiked samples. The lowest concentration distinguished by the electronic tongue was 493 μg L^?1, a lower value than the sensory threshold determined. These findings suggest that for the detection of 4‐EC in Merlot, the e‐tongue may be more sensitive than some consumers and the e‐tongue may be a suitable methodology for detection of subthreshold concentrations of chemical compounds in wine.     

Physico-chemical properties of 3-methoxy-2-nitrobenzoates of some rare earth elements（Ⅲ）

The complexes of 3-methoxy-2-nitrobenzoates of Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Tb(III), Er(III) and Tm(III) with the formula: Ln(C8H6NO5)3·2H2O, where Ln=lanthanides(III), were synthesized and characterized by elemental analysis, Forier transform irtrared (FTIR) spectroscopy, magnetic and thermogravimetric studies and also by X-ray diffraction (XRD) measurements. The complexes had col- ours typical for Ln(III) ions. The carboxylate groups bound as bidentate chelating. On heating to 1173 K in air they decomposed in the same way, at first, dehydrated in one step to anhydrous salts, and then decomposed to the oxides of respective metals with intermediate formation of the oxycarbonates. The enthalpy values of the dehydration process changed from 133.72 to 44.50 kJ/mol. Their solubility in water at 293 K was of the order of 10-4 mol/dm3. The magnetic moments of analysed complexes were determined by Gouy’s method in the range of 76-303 K.