Production of D-lyxose from D-glucose by microbial and enzymatic reactions

D-arabitol was first prepared from D-glucose using Candida famata R28. The reaction gave 5.0% D-arabitol from 10.0% D-glucose. D-arabitol was then almost completely converted to D-xylulose using Acetobacter aceti IFO 3281. Finally, D-lyxose was prepared from D-xylulose enzymatically using L-ribose isomerase from toluene-treated cells of Acinetobacter sp. strain DL-28. The isomerization reaction progressed steadily and the concentration of D-xylulose increased from 1.0 to 10.0%. About 70% of D-xylulose was converted to D-lyxose in all cases. Separation of residual D-xylulose from the reaction mixture is very difficult to achieve by column chromatography, but D-xylulose could be selectively degraded easily using Saccharomyces cerevisiae IFO 0841. The product was crystallized and was confirmed to be D-lyxose by HPLC, 13C-NMR spectra, IR spectra analysis, and optical rotation measurement.     

Determination of Antioxidant Activity and Polyphenols Content in Chips by Raman and IR Spectroscopy

The application of vibrational spectroscopy for the determination of total polyphenols content, antioxidant activity, colour parameters, and fat level in chips originated from yellow-, red- and purple-fleshed potato varieties is reported. Raman, infrared (IR) and near-infrared (NIR) spectra of the laboratory-prepared chips were collected. Combining spectral data with the results of reference analyses, partial least squares regression models were built. To characterise and compare the elaborated models, the relative standard errors of prediction were calculated for calibration and validation sets. In the case of total phenolics quantification by Raman/IR/NIR techniques, these errors (%) amounted to 4.0/7.0/7.1 and 6.4/8.5/8.4 for calibration and validation samples, respectively, whereas they were 4.9/7.7/4.8 and 6.6/8.3/6.8 for antioxidant activity. The obtained results demonstrate that both infrared and Raman spectroscopy can effectively replace commonly used extraction methods. It follows that Raman spectroscopy has the highest potential to be adopted for the online potato-derived product analysis.     

Applications of chitosan for improvement of quality and shelf life of foods: a review

ABSTRACT:  Chitosan is a modified, natural biopolymer derived by deacetylation of chitin, a major component of the shells of crustacean. Recently, chitosan has received increased attention for its commercial applications in the biomedical, food, and chemical industries. Use of chitosan in food industry is readily seen due to its several distinctive biological activities and functional properties. The antimicrobial activity and film-forming property of chitosan make it a potential source of food preservative or coating material of natural origin. This review focuses on the applications of chitosan for improvement of quality and shelf life of various foods from agriculture, poultry, and seafood origin.     

Transformation kinetics and potential availability of specifically-sorbed phosphate in soils

The improvement of P management in agriculture and environment requires a good understanding of residual effect of applied P in soils. The specific adsorption of P on variable charge minerals has been considered as the major mechanism that leads to a very low utilization of P fertilizer by crops within a growing season in Chinese red soils. Soil incubation and isotope tracing analysis were carried out to examine the transformation kinetics and potential availability of added specifically sorbed ³²P in two pH contrasting light textured soils. The ³²P recovered by 0.5 M NaHCO₃ extraction and microbial biomass-P measurement from the added specifically sorbed ³²P in the soils was well described by a first-order reaction and a Langmuir-type kinetic model, with correlation coefficients (R) being, on average, 0.938 and 0.959, respectively. The half-life (t_1/2, from the first-order model) of the four tested mineral-P complexes ranged from 29 to 47 d in the acid sandy soil and 33 to 105 d in the neutral silty soil. Goethite-P was the most stable among the four tested mineral-P complexes. The potential availability of the mineral complex P (q _m , in percent of total ³²P added) obtained from the Langmuir equation ranged from 43.7 to 90.9% for the four mineral-P complexes, and decreased in the order: Al oxide-P (90.9%) > montmorillonite-P (86.2%) > kaolinite-P (77.5%) > goethite-P (60.2%) in the acid sandy soil, whereas the order was Al oxide-P (89.3%) > kaolinite-P (86.2%) > montmorillonite-P (82.6%) > goethite-P (43.7%) in the neutral silty soil. Based on the release rate and potential availability, kaolinite-P and Al oxide-P could be important sources for residual effect of applied P in variable-charge soils. The goethite-P has the lowest release rate and potential availability among the mineral-P complexes, implying that iron oxides may be the most important variable-charge mineral responsible for P fixation in the Chinese red soils.     

Synthesis,microstructure and optical characterization of zirconium oxide nanostructures

Zirconium oxide (ZrO₂) nanostructures were synthesized by hydrothermal route. Surface morphology analysis depicts the formation of the nanobars and hexagonal-shaped nanodiscs at different synthesis conditions. The structural analysis confirms that the as-synthesized ZrO₂ product is of pure monoclinic phase (m-ZrO₂) with crystallite size of about 25 nm. The product consists of monodispersed nanoparticles of uniform composition, high purity, and crystallinity. The Raman spectra are quantitatively analyzed and the observed peaks are attributed to various vibration modes of the m-ZrO₂. The UV–vis absorption spectrum showed a strong absorption peak at about 292 nm and the estimated optical band gap was around 3.57 eV. Photoluminescence (PL) spectrum of ZrO₂ nanostructure showed a strong and broad emission peak at around 410 nm at room temperature, which can be attributed to the ionized oxygen vacancy in the material.     

Tuning of the Cloud Point of Promethazine Hydrochloride with Surfactants and Polymers

The effect of additives (surfactants and polymers) and pH on the clouding behavior of promethazine hydrochloride (PMT, a phenothiazine drug) was investigated. Cloud point (CP) decreases with increase in pH due to deprotonation of drug molecules. The same trend occurs in the presence of surfactants. However, at constant pH, and depending on their structure and nature, these additives behave differently. Anionic surfactants show peaked behavior, whereas cationic (conventional as well as geminis) and non-ionic surfactants increase the CP, although the mechanisms differ. Cationic surfactants hinder drug association (due to interaggregate repulsion) resulting in an increase in CP, while non-ionic surfactants form mixed micelles with the drug, increasing micelle hydration and CP. Polymers can cause both a decrease as well as an increase in CP, depending on their molecular weight. A large CP increase (with the increase in surfactant concentration) for gemini surfactants suggests they are excellent candidates for drug delivery.

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Electrochemical applications of net-benefit analysis via Bayesian probabilities

By means of three specific applications to electrochemical science, this paper demonstrates the usefulness of the net-benefit principle and Bayesian (posterior) probabilities in deciding whether equipment in an electrochemical laboratory or plant should be repaired or replaced.     

Dielectric Constant,Metallization Criterion and Optical Properties of CuO Doped TeO2–B2O3 Glasses

Journal of Inorganic and Organometallic Polymers and Materials - Copper oxide doped TeO2–B2O3 glass system with empirical formula;...