Effect of lentil and bean flours on rheological and baking properties of wheat dough

The potential of legume flours (lentil and bean) in bakery applications was investigated. The study indicated that legume flours were characterised by high protein (27.30–27.35 mass %) and total dietary fibre (14.91–21.52 mass %), relatively high water holding capacity (4.71–5.42 g g^?1), and good emulsifying properties (emulsifying capacity: 32.73–46.96 cm³ per 100 cm³ and emulsion stability: 60.52–90.90 cm³ per 100 cm³). Fine wheat flour was partially substituted with 10 mass %, 20 mass %, and 30 mass % levels of lentil and bean flours in order to study their farinographic characteristics and baking behaviour. The addition of legume flours increased water absorption capacity (from 58.50 mass % to 74.90 mass %) and dough development time (from 3.50 min to 5.50 min), whereas dough stability was reduced (from 6.67 min to 2.30 min). The presence of legume flours in dough negatively affected the physical parameters of baked rolls and resulted in the reduction in volume, specific volume, and cambering. Sensory evaluation showed that the most acceptable baked rolls were obtained when the wheat-legume blend flour containing 10 mass % of legume flour was applied. Higher levels of legume flours in the products adversely affected the shape, crust colour, crumb elasticity, and hardness of the final products.     

Selective photometric determination of low conentrations of selenium(IV) and selenium(VI) in bottled drinking water

A procedure is developed for the selective photometric determination of selenium(IV) in bottled drinking water by the oxidation of Methylene Blue in 1 M HCl to colorless decomposition products and of selenium(VI) by its interaction with the specified reagent at pH 5–6 with the formation of a colored ion pair. The limits of detection are 1 and 0.8 µg/L, respectively. At the concentration of selenium(IV) 2 µg/L, the admissible weight ratios are: SeO₄^2-, Br₃^- (1: 20); Br^– (1: 60); I^–, IO₃^- and IO₄^- (1: 100). At equal concentration of selenium(VI), the following species: SeO₄^2-(1: 20); Br₃^-, Br^–, I^–, IO₃^-, and IO₄^- (1: 100) do not interfere with the determination. Other anions and cations present in highly mineralized waters do not interfere with the determination. The relative error of determination is 8–10% in the concentration range 2–10 µg/L of selenium(IV) and selenium(VI) and does not exceed 5% in their concentration range of 10–100 µg/L.     

SYNTHESES OF SOME 35S-LABELLED ORGANIC COMPOUNDS AT BORIS KIDRIČ INSTITUTE - VINČA

Abstract

³⁵-labelled organic compounds are widely used in different fields: medicine, chemistry, biochemistry, biology, etc. Some of these compounds are known as chemoprotectors and ³⁵S-labelled forms are used in the investigation of such protective mechanism. Details of the chemical and biochemical syntheses of some ³⁵S-labelled organic compounds are given in the paper: DL-cysteine hydrochloride-³⁵S (1-amino-2-mercaptopropionic acid), vitamin B₁-³⁵S (thiamin hydrochloride), thiourea-³⁵S, carbon disulphide-³⁵S and L-methionine-³⁵S (1-amino-4-methyl- thiobutyric acid). Products of high specific activities are obtained: 5–10 mCi/mM DL-cysteine hydrochloride-³⁵S; 60–120 mCi/mM vitamin B₁-³⁵S; 100–200 mCi/mM thiourea-³⁵S; 20–100 mCi/mM carbon disulphide- ³⁵S and 1–10 Ci/mM L-methionine-³⁵S. All the products are of high chemical and radiochemical purity, which were determined by thin layer chromatography.     

Sensitive spectrofluorimetric determination of zinc at ultra-trace levels

An ultra-trace method based on the reaction of zinc with salicylthiocarbohydrazone (SATCH) and Triton X-100 as a non-ionic surfactant was developed for the fluorimetric determination of zinc at the picogram level. The reaction is carried out in the pH range 4.4–4.7 in an aqueous ethanolic medium [52% (v/v) ethanol]. The influence of the reaction variables is discussed. The detection limit is 10 pg ml^?1 and the range of application is 0.01–500 μg l^?1, with an optimum range of 0.04–400 μg l^?1. The relative standard deviations are 0.68% (0.01–0.1 μg l^?1 of zinc), 0.41% (0.1–1.0 μg l^?1 of zinc), 0.64% (1–10 μg l^?1 of zinc), 0.82% (10–100 μg l^?1 of zinc) and 0.15% (100–500 μg l^?1 of zinc). The method is highly sensitive and selective in the presence of Cd^II and Hg^II. The effect of interferences from other metal ions and anions was studied; the masking action is discussed. The advantages of the proposed method include its high sensitivity, simplicity and selectivity.     

The synthesis of di- and tetramethyl substituted macrocyclic polyether-diester ligands

Three series of macrocyclic polyether-diester ligands have been prepared from dimethyl triethylene glycol ( 20 ), two dimethyl tetraethylene glycols ( 21,23 ), dimethyl pentaethylene glycol ( 22 ) and tetramethyl tetraethylene glycol ( 24 ) and diglycolyl chloride (products 5–9 ), thiadiglycolyl chloride (products 10–14 ) and 2,6-pyridine dicarbonyl chloride (products 15–19 ). The eighteen-membered rings ( 6 and 16 ) formed solid potassium thiocyanate complexes. The eighteen- and twenty-one-membered ring compounds 6–8 and 16–18 complexed with benzylammonium perchlorate in methylene chloride-d₂ as shown by significant chemical shift changes in the ¹H nmr spectra.     

Single robust RP-HPLC analytical method for quantification of curcuminoids in commercial turmeric products,Ayurvedic medicines,and nanovesicular systems

A single robust reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated as per International Conference on Harmonization guidelines for the accurate quantification of curcuminoids in commercial turmeric products, Ayurvedic medicines, and nanovesicular systems. The proposed chromatographic method was found to be specific, linear (r²?≥?0.999), precise at intra- and inter-day levels (percentage relative standard deviation <2.0%), accurate (percentage recovery 99.14–102.29%), and robust. The limits of detection and quantification were found to be 7.40 and 24.70?ng?mL^?1 for curcumin, 9.24 and 30.80?ng?mL^?1 for demethoxycurcumin, and 6.48 and 21.61?ng?mL^?1 for bisdemethoxycurcumin, respectively. Among different commercial turmeric products and Ayurvedic medicines tested, the contents of curcumin (3.54?±?0.06–25.8?±?0.08?mg?g^?1), demethoxycurcumin (1.28?±?0.02–9.97?±?0.03?mg?g^?1), and bisdemethoxycurcumin (0.50?±?0.01–5.97?±?0.01?mg?g^?1) varied significantly. The developed method was effectively applied to the determination of encapsulation efficiency of curcuminoids (ranged between 84.33?±?3.50 and 96.59?±?2.53%) in the nanovesicular systems. In conclusion, the reported method is suitable for the analysis of curcuminoids in a wide variety of turmeric products and used for the quality control of products that contain curcuminoids.     

Selective photometric redox determination of periodate and iodate ions in bottled drinking water

method has been developed for the selective photometric redox determination of periodate and iodate ions in bottled drinking water based on redox reactions of analytes with Methylene Blue with different duration of processes, products of which form the analytical signal. The limits of detection for periodate and iodate ions are 0.5 and 0.2 µg/L, respectively. The allowable weight ratios for concomitant ions for (at the analyte concentration 2 µg/L) are as follows: I^–, Br^–, IO₃^–, BrO₃^–, ClO^–, CIO^–, CIO₂^–, CIO₃^– and CIO₄^–(1: 100); and for IO₃^– (1 µg/L) are: BrO₃^–₂^–, NO (1: 60), CIO^–, CIO₂^–, (1: 100), and I^–, Br^–, IO₄^–, CIO₃^–, and CIO₄^– (1: 200). The HCIO₃^–, Cl^–, and SO₄^2- anions and Ca²⁺, Mg²⁺, Na⁺, K²⁺, and NH₄⁺ cations are macrocomponents of drinking water and at total concentrations up to 10 g/L do not affect the results of analysis. In the concentration range 1–10 µg/L of IO₄^– andIO₃^–, the total error of determination is 5–7%.     

Synthesis and characterization of Si-Zr-Mo nanocomposite as a rapid and efficient catalyst for aromatization of Hantzsch 1,4-dihydropyridines

Nanocomposite of Silica-zirconia-molybdate designated as Si-Zr-Mo was prepared via the reaction of the in situ generated zirconium-tetra octanoxide [Zr(Oct)₄] through condensation of zirconium-tetra-n-butoxide and 1-octanol in a sol–gel method with sulfuric acid and tetraethylorthosilicate (TEOS) followed by grafting of MoO₄^2? on modified silico zirconia nanocomposite under reflux conditions. The prepared nanocomposite was characterized using inductively coupled plasma (ICP), N₂ sorption isotherms, transmission electron microscopy (TEM), and FT-IR spectroscopy. The as prepared nanocomposite had a surface area and pore dimension of 140 m²/g and 1.48 nm, respectively. The morphology of sulphated silico zirconia nanocomposite after immobilization MoO₄^2? has been changed from nanoparticles to nanaorods. It was found that the synthesized nanocomposite successfully catalyze the oxidative dehydrogenation of 1,4-dihydropyridines (1,4-DHPs) with 92–100% conversion and 80–100% selectivity toward the desired products.     

PRODUCTION OF SOME INORGANIC FORMS OF 35S FOR CHEMICAL SYNTHESIS OF LABELLED ORGANIC COMPOUNDS

Abstract

Some inorganic forms of ³⁵S are used as starting material for some chemical syntheses of labelled organic compounds. The choice depends on the desired characteristics of the labelled compound. Preparation of barium sulphate- ³⁵S, barium sulphide- ³⁵S, ferrous sulphide- ³⁵S, sodium sulphide- ³⁵S and elementary form of ³⁵S, is described. The characteristics of the products, along with determination methods, are given. The products are obtained with high specific activities of: 5–15 Ci/g S barium sulphate-³⁵S; 1–5 Ci/g S barium sulphide- ³⁵S; 100–500 mCi/g S ferrous sulphide-³⁵S; 1–5 Ci/g sodium sulphide-³⁵S and 100–500 mCi/g S elementary ³⁵S.     

Pyrolysis of pine needles: effects of process parameters on products yield and analysis of products

Pyrolysis of pine needles was carried out in a semi-batch reactor. The effects of pyrolysis parameters such as temperature (350–650 °C), heating rate (10 and 50 °C min^?1), nitrogen flow rate (50–200 cm³ min^?1) and biomass particle size (0.25–1.7 mm) were examined on products yield. Maximum bio-oil yield of 43.76% was obtained at pyrolysis temperature of 550 °C with a heating rate of 50 °C min^?1, nitrogen flow rate of 100 cm³ min^?1 for biomass particle size of 0.6 < d _p < 1 mm. The characterization of pyrolysis products (bio-oil, bio-char) has been made through different instrumental methods like Fourier transform infrared spectroscopy, gas chromatography–mass spectrometry, nuclear magnetic resonance spectroscopy (¹H NMR), X-ray powder diffraction, field emission scanning electron microscope and Brunauer–Emmett–Teller surface area analysis. The empirical formula of the bio-oil and bio-char was found as CH_1.47O_0.36N_0.005 and CH_0.56O_0.28N_0.013 with heating value of 26.25 and 25.50 MJ kg^?1, respectively. Results show that bio-oil can be potentially valuable as a renewable fuel after upgrading and can be used as a feedstock for valuable chemicals production. The properties of bio-char reveal that it can be used as solid fuels, as a cheap adsorbent and as a feedstock for activated carbon production.     

Quantitative analysis of surfactant deposits on human skin by liquid chromatography/electrospray ionisation tandem mass spectrometry

Surfactants are commonly used as cleansing agents and yet there are concerns that they may also have a role in skin irritation. The lack of suitable methods for the quantitative and qualitative analysis of surfactant deposition on skin has hindered the in‐depth investigation of such effects. Here, we report the application of reversed‐phase liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI‐MS/MS) assays for two surfactants commonly used in consumer products, namely sodium lauryl ether sulfate (SLES) and laurylamidopropyl betaine (LAPB), to a baseline study aiming to assess deposition levels on human skin. The linearity of the assays was established at 3–20 ng, with coefficient of variation below 5%. The detection limits were 100 pg for LAPB and 1 ng for SLES; quantitation limits were 500 pg for LAPB and 2.5 ng for SLES. The baseline study was conducted using a panel of 40 healthy volunteers. Skin extract samples were taken in triplicate from forearms, using ethanol. SLES was detected on most volunteers, with 75% of them having SLES deposits in the range of 100–600 ng/cm². LAPB was detected on the skin of all volunteers with 85% of them having deposit levels within the concentration range of 1–100 ng/cm². These results demonstrate the extent to which commonly used surfactants remain on the skin during the day. The analytical methods reported here can be applied to the investigation of surfactants in relation to general skin condition and to the development and optimisation of new consumer wash products. Copyright © 2010 John Wiley & Sons, Ltd.     

Total Synthesis of Pradimicinone,the Common Aglycon of the Pradimicin–Benanomicin Antibiotics

A benzo[ a ]naphthacenequinone core, an amino acid, and a disaccharide are the constituents of pradimicin–benanomicin antibiotics 1 (R¹=disaccharide), a class of natural products with significant antifungal and anti-HIV activities. The first total synthesis of pradimicinone (benanomicinone, 1 ; R¹=H), the common aglycon of this class of natural products, has now been achieved based on the transmission of chirality during the pinacol cyclization of 2,2′-biaryldicarbaldehydes.     

RP-LC Analysis and Hydrolytic Degradation Profile of Racecadotril

A sensitive, stability-indicating liquid-chromatographic method for analysis of racecadotril in the presence of its degradation products has been developed and validated. Efficient chromatographic separation was achieved on a C₁₈ column with a simple isocratic mobile phase—60:40 methanol–water. Quantification was by photo-diode array (PDA) detection at 220 nm. The linearity of the method was excellent over the range 1–32 μg mL^?1. The method was sensitive, with low limits of detection (20 ng mL^?1) and quantification (100 ng mL^?1). The recovery of the method was consistently good (98.7–100.9%), with low (<1%) intra-day and inter-day relative standard deviation. Robustness studies confirmed that peak area was unaffected by small changes in temperature, and mobile phase composition and flow rate. Both alkaline and acidic hydrolytic degradation were performed in methanolic solution. In alkaline medium the drug was degraded immediately; it was degraded within 90 min in acidic medium. The validated, stability-indicating, method was used for analysis of racecadotril in pharmaceutical dosage form and also to reveal the hydrolytic degradation profile of the racecadotril.     

Destruction of 2,4 Dichlorophenol in an Atmospheric Pressure Dielectric Barrier Discharge in Oxygen

The processes of degradation of 2,4-dichlorophenol (2,4-DCP) under the action of atmospheric pressure of dielectric barrier discharge (DBD) in oxygen were studied. It was shown that the degradation of 2,4-DCP proceeds efficiently. Degree of decomposition reaches 90%. The degradation kinetics of 2,4-DCP obeys the formal first-order kinetic law on concentration of 2,4-DCP. The effective rate constants depend weakly on the experimental conditions and are equal to ~0.2 s^?1. Based on experimental data, the energy efficiency of decomposition of 2,4-DCP was determined. Depending on the conditions, the energy efficiency was in the range of (8–90) × 10^?3 molecules per 100 eV. The composition of the products was studied by gas chromatography (GC), gas chromatography–mass spectrometry (GC–MS), energy-dispersive X-ray spectroscopy (EDX), attenuated total reflection-fourier transform infrared (ATR-FTIR) spectroscopy, electron spin resonance (ESR) spectroscopy and UV/Visible spectroscopy. It was shown that about ~20% of 2,4-DCP is converted to CO₂, while the other part forms an organic film on the reactor wall. The substance formed is close to the carboxylic acids in chemical composition and exhibits electrical conductivity and paramagnetic properties. Almost all of the chlorine contained in the 2,4-DCP is released into the gas phase. The active species of the afterglow react with liquid hexane, forming the products of its oxidation. Some assumptions regarding the pathway of the process are discussed.     

Matrix-Assisted Laser Desorption Mass Spectrometry of Biotransformation Products of Dynorphin A in Vitro

The utility of matrix-assisted laser desorption mass spectrometry for characterizing products of in vitro processing of synthetic dynorphin A (Dyn A) peptides in biologic matrices is described. A series of laser desorption matrices were tested for their response to Dyn A (1–6), Dyn A (1–7), Dyn A (1–8), Dyn A (1–9), Dyn A (1–l0), Dyn A (1–13), Dyn A (2-17), and Dyn A (1–17). α-Cyano-4-hydroxycinnamic acid was chosen as a suitable matrix for subsequent studies. Mass spectra of dynorphin peptides indicated a good signal-to-noise response down to (1) 10 fmole of Dyn A (1–10) amide standard in aqueous acidic solution and (2) a concentration of 10^-7 M for seven dynorphin peptides spiked into human plasma. Two examples of the mass spectrometric analysis of the products of in vitro processing are presented: Dyn A (1–13) and Dyn A (1–17) in human blood. The presence and identity of processed peptides can be simply inferred from the molecular masses provided by the mass spectrometric measurement without extensive sample purification. A comparison of matrixassisted laser desorption mass spectrometry is made with high-performance liquid chromatography.     

Separation of zirconium from fission products in silica gel—nitric acid systems

A method for the separation of zirconium from fission products based on the system 100–200 mesh silica gel—2.0 M nitric acid is described. Decontamination factors are over 500 for ⁹⁵Nb, ¹⁰⁶Ru, ¹²⁴Sb, ¹³⁷Cs, molybdate and uranium(VI), and the yield of zirconium is 98 %.     

Radiation-induced oxidation of polyethylene,ethylene–butene copolymer,and ethylene–propylene copolymer

Oxygen consumption and yield of oxidation products during γ-irradiation were studied on five types of polyethylene (PE), ethylene–butene copolymer (EB), and ethylene–propylene copolymer (EPR) using gas chromatography, mass spectrography, and high-resolution NMR. Samples were irradiated in oxygen under pressure from 0 to 500 torr by ⁶⁰Co γ-rays up to 20 Mrad at 22–25°C. In enough oxygen, oxygen consumption and yield of oxidation products are independent of oxygen pressure for low-density PE, EB, and EPR. The G values of oxygen consumption were 14–18.4 for PE, 11.6 for EB at 1 × 10⁶ rad/h, and 8.3 for EPR at 2 × 10⁵ rad/h. The oxidation products determined were carboxylic acid (? CH₂? CO? OH), H₂O, CO₂, and CO. The oxygen consumption and oxidation products for PE were found to increase with increasing crystallinity.     

A Convenient Synthesis of Pyrazole‐imidazoline Derivatives by Microwave Irradiation

A series of 28 hybrids pyrazole‐imidazolines 1a – n and 2a – n were synthesized by a new methodology using microwave irradiation, in short time (20–30 min), in low power (50–70 W), and in 34–92% yield. Among all methodologies evaluated, no side products were obtained. All derivatives were completely characterized by FT–IR, ¹H and ¹³C NMR, GC–MS, and HRMS.     

Cu determination in crude oil distillation products by atomic absorption and inductively coupled plasma mass spectrometry after analyte transfer to aqueous solution

Cu was determined in a wide range of petroleum products from crude oil distillation using flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICP-MS). Different procedures of sample preparation were evaluated: (i) mineralization with sulfuric acid in an open system, (ii) mineralization in a closed microwave system, (iii) combustion in hydrogen–oxygen flame in the Wickbold's apparatus, (iv) matrix evaporation followed by acid dissolution, and (v) acidic extraction. All the above procedures led to the transfer of the analyte into an aqueous solution for the analytical measurement step. It was found that application of FAAS was limited to the analysis of the heaviest petroleum products of high Cu content. In ICP-MS, the use of internal reference method (with Rh or In as internal reference element) was required to eliminate the matrix effects in the analysis of extracts and the concentrated solutions of mineralized heavy petroleum products. The detection limits (in original samples) were equal to, respectively, 10, 86, 3.3, 0.9 and 0.4 ng g^− 1 in procedures i–v with ETAAS detection and 10, 78, 1.1 and 0.5 ng g^− 1 in procedures i–iii and v with ICP-MS detection. The procedures recommended here were validated by recovery experiments, certified reference materials analysis and comparison of results, obtained for a given sample, in different ways. The Cu content in the analyzed samples was: 50–110 ng g^− 1 in crude oil, < 0.4–6 ng g^− 1 in gasoline, < 0.5–2 ng g^− 1 in atmospheric oil, < 6–100 ng g^− 1 in heavy vacuum oil and 140–300 ng g^− 1 in distillation residue.     

The Destruction of Carbon Tetrachloride Dissolved in Water in a Dielectric Barrier Discharge in Oxygen

The kinetics of decomposition of tetrachloromethane (TCM) in its aqueous solutions and the kinetics of decomposition products formation was investigated under the action of DBD at atmospheric pressure in oxygen in a falling-flow reactor. The range of initial concentrations of TCM was 25–325 μmol/l, the discharge power—2–11 W and O₂ flow rates—1–3 cm³/s. It is shown that the kinetics of the TCM decomposition can be described by the equation of pseudo-first kinetic order. The rate constant depended weakly on the discharge parameters and was?~?5 s^?1. The energy efficiency of the decomposition, depending on the parameters, was 0.1–1.3 molecules per 100 eV. When the residence time of the solution with the discharge zone is more than 1 s, it is possible to achieve almost 100% degree of TCM decomposition. It is shown that the main products of the TCM decomposition in the liquid phase are aldehydes and Cl^? ions, and in the gas phase—the molecules CO and CO₂. The results for energy efficiency are compared with the results obtained in other AOP’s processes (Fenton process, photocatalytic process, the radiation process by the action of high-energy electron flux). It is shown that the action of the DBD is more effective than the action of the above processes.