教学课程资源库 更多>>

关键词： Ezetimibe   Aspirin   DSC   Eutectic   Dissolution   Fixed-dose  

摘要： The objective of this work was to investigate binary pharmaceutical mixtures of ezetimibe (EZT) and aspirin (ASA) in order to identify whether the occurrence of eutectic in this system has an effect on EZT dissolution improvement. Ezetimibe-aspirin (EZT-ASA) solid dispersions prepared by grinding in the whole range of compositions were characterized using differential scanning calorimetry (DSC) for purpose to describe solid-liquid phase equilibrium diagram. The occurrence of interactions between ingredients was excluded by Fourier transform infrared spectroscopy and X-ray powder diffractometry. Dissolution studies have shown that the mixtures containing from 10 to 60 mass% of EZT (53.5 mass% of EZT in eutectic composition) have released ezetimibe faster than a sample of pure drug. Moreover, ASA is released more quickly from all obtained dispersions than from powder alone. Our studies have shown that obtained mixtures are useful to obtain the fixed-dose combinations, capable to deliver these two APIs together in a single system with enhanced dissolution of EZT and ASA.

关键词： gelatin   extraction   property   swim bladder   sturgeon  

摘要： BACKGROUND Gelatin is traditionally produced from mammals and widely applied in the food industry. The production is tedious, time-consuming and environment-unfriendly, while the application is restricted because of zoonosis risk and religious sentiment. RESULTS Gelatin was extracted by hot water from sturgeon swim bladder after defatting with alcohol and hexane. The yield reached to 94.15% under the optimized conditions of 50 degrees C, 30 min and 10 mL g(-1). Its amino acid and subunit profiles were similar to type I collagen. Compared to commercial porcine, bovine and piscine gelatins, it exhibited higher whiteness (3.38), emulsion activity (171.76 m(2) g(-1)), gel strength (853.23 g), water-holding capacity (92.37%) and viscoelasticity (0.03). But the transmittance (40.56% at 450 nm and 59.07% at 620 nm), emulsion stability (30.09 min), foam expansion (203.00) and stability (26.92), gelling (16.88 degrees C) and melting temperature (21.80 degrees C) were lower. While the pH (6.87) and viscosity (28.60 mPa s) were moderate. Moreover, it made better hydrogels and nanofibers. CONCLUSION Gelatin was extracted from sturgeon swim bladder using a clean and efficient approach, and exhibited unique properties and great potential for the food industry.

关键词： water vapor   coherent phase   exclusion zone   redox potential   pH   infrared   microdroplets  

摘要： Water vapor absorbs well in the infrared (IR) region of the spectra. On the other hand, it was recently demonstrated that IR radiation promotes formation of the so-called exclusion zones (EZ) at the interfaces between hydrophilic surfaces and water. EZ-water properties differ significantly from that of bulk water. It was studied for the first time whether treatment of water with humid air irradiated with IR-C band could change its physical-chemical properties, making it EZ-water-like. Humid air irradiated with IR was called coherent humidity (CoHu). Redox potential and surface tension decreased in deionized water and mineral water samples that were treated with CoHu, while dielectric constant increased in such water samples. After such treatment of carbonate or phosphate buffers, their buffer capacity against acidification and leaching significantly increased. No such changes were observed in water samples treated with non-irradiated humid air. Thus, after treatment of tested aqueous systems with humid air exposed to IR radiation, their properties change, making them more like EZ-water. The results suggest that IR irradiation of humid air converts it into a carrier of a certain physical signal that affects water properties.

关键词： Phycocyanin   Liposomes   Spectroscopy   Antiradical   Antioxidant  

摘要： This study describes the physicochemical properties of soybean asolectin (ASO) liposomes loaded with phycocyanin (Phy) extracted from Spirulina sp. LEB 18. The effects of Phy in the liposomes' properties were investigated by Fourier transform infrared spectroscopy (FTIR), H-1 and P-31 nuclear magnetic resonance (NMR), zeta zeta-potential, dynamic light scattering (DLS) and ultraviolet-visible (UV-vis) techniques. Phy restricted the motion of ASO polar and interface groups and disrupted the package arrangement of the lipid hydrophobic regions, as a likely effect of dipolar and 't interactions related to its amino acid residues and pyrrole portions. These interactions were correlated to antiradical/antioxidant Phy responses obtained by 2,2-diphenyl-1-picrylhidrazil (DPPH) assay, thiobarbituric acid reactive substances (TBARS) and ferric reducing antioxidant power (FRAP) methods, and discussed to bring new chemical perspectives about Phy-loaded liposomes-related nutraceutical applications in inflammatory and viral infection processes.

关键词： halloysite   boehmite   catalyst supports   hydroprocesses   mechanical strength  

摘要： Hydroprocessing catalyst supports based on aluminosilicate halloysite nanotubes with various alumina contents were synthesized. Their textural characteristics and acidic properties were investigated. The component composition and strength profile of cylindrical extrudates of the aluminosilicate supports were studied. The influence of the mass content of boehmite used as a binder on the physicochemical properties of the materials was established. The crush strength of the synthesized carriers based on aluminosilicate nanotubes was shown to be comparable or superior to those of industrial analogs.

关键词： Fresco cheese   Physicochemical composition   Microbial diversity   High‐   throughput sequencing  

摘要： The aim of the present study was to characterise the physicochemical and the microbiota composition of the artisanal Fresco cheese from Sonora. For this, cheeses of 18 small-scale artisanal dairies were analysed. The chemical composition and the microbiological quality were determined by standard methods, and bacterial diversity by high-throughput sequencing. The physicochemical composition showed differences (P < 0.05) among dairies, and the principal component analysis aggrupation of 66% dairies. The analysis by region did not show difference (P < 0.05).The microbiota most abundant were Firmicutes, Proteobacteria and lactic acid bacteria in phyla and genera, respectively. These results provide insights on the characterisation of the Fresco cheese from Sonora.

关键词： Biopolymer aqueous dispersions   Food hydrocolloids   Food organic acids   Food polysaccharides  

摘要： Chitosan (CH) is a biopolymer derived from chitin, which is the second most abundant polysaccharide in nature, after cellulose. Their functional groups -NH(2)and -OH can form intermolecular interactions with water and other molecules, enabling a variety of applications for CH. -NH(2)groups become protonated in acidic solutions, causing an increase in electrostatic repulsion between CH chains, which facilitates their dispersion in aqueous media. Aqueous solutions of acetic acid and/or acetates buffers have been used to disperse CH, but may not be adequate for technological applications, espeacially because of the strong flavor this acid confers to formulations. In this study, 0.125;0.250;0.500;0.750 and 1.000 g (100 g)-1CH dispersions were prepared in acidic aqueous media (50 mmol L-1), not only with acetic (AA), but also with glycolic (GA), propionic (PA), or lactic (LA), acid aiming to evaluate the effects of biopolymer concentration and type of organic acid on: electrical conductivity, pH, density and rheological characteristics of dispersions. Moreover, zeta potential values of CH chains dispersed in these acidic aqueous media were assessed. pH, density and consistency index were influenced by the biopolymer concentration, but not by the acid type. At a given biopolymer concentration, zeta potential signs (+) and values suggested that electrostatic interactions between CH chains and counter-anions occurred, regardless of the type of the organic acid. Thus, at least from a physicochemical point of view, GA, PA or LA showed to be suitable to replace AA when preparing dispersions containing from 0.125 to 1.000 g (100 g)-1CH for technological purposes, such as thickening or stabilizer in formulated food products.

关键词： Chia oil   Encapsulation   Co-current arrangement   Tall and short-form dryers   Oxidative stability   Theoretical drying kinetic model  

摘要： A design of experiments for chia oil microencapsulation was performed in two co-current dryers: a tall-form (TF-SD) and a short-from spray dryer (SF-SD). The effects of air inlet temperature and volumetric feed rate were analyzed. The responses were the outlet air properties, physico-chemical characteristics of powders, the estimated droplet evaporation time and the additional exposure time of dry particles in the chamber. The droplet evaporation time was calculated by considering evaporation in still-air and drying only during the constant rate period. The calculated values were 69.67-105.98 ms and 1.45-2.74 s for TF-SD and SF-SD, respectively. The contact of product with hot air caused by back-mixing and the extended residence time in the chamber may explain the poor oxidative stability of powders from SF-SD. The peroxide index values were 1.72-4.51 and 16.10-96.65 meq. O-2/kg oil for TFSD and SF-SD, respectively. The oxidative stability indexes were 5.14-6.52 and 0.26-0.80 h for TF-SD and SF-SD, respectively. A global optimization was performed for TF-SD since it yielded products with the best chemical quality. The process condition that simultaneously optimized the responses was 160 degrees C x 2.8 mL/min. Finally, additional characterization of the optimal powders ensured the stability of the core: fatty acid profile before and after in-vitro digestion, thermogravimetric analysis, differential scanning calorimetry, moisture sorption behavior and surface morphology. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

关键词： electrochemical corrosion   oxides   oxygen implantation   Cu-Mn alloy   surface   chemical structure   atomic structure  

摘要： The chemical composition and structure of the Cu-Mn alloy after modification with oxygen ions with an energy of 10-30 keV and a dose of 10(17) cm(-2) have been investigated. Changes in the type of chemical bonding and atomic structure in irradiated Cu-Mn samples have been studied by X-ray photoelectron spectroscopy and X-ray diffraction. Electrochemical studies of ion-modified surfaces have been performed by measuring the anodic potentiodynamic polarization curves in a neutral borate buffer solution, hydrochloric acid, and potassium hydroxide.

关键词： Natural lacquers   Urushiol   Laccol   Catechol lipids   Mixing compositions   Physicochemical properties  

摘要： An evaluation of the catechol lipid compositions of natural lacquer materials and their correlation with the physicochemical properties of lacquer films have become important issues for the advancement of natural lacquer technologies. Here, a convenient method for evaluating the relative composition of urushiol and laccol catechol lipids in natural lacquers using Fourier transform infrared (FT-IR) analysis is proposed. Urushiol and laccol exhibited different characteristic peaks in the FT-IR spectrum owing to the different stereoisomer structures of the conjugated dienes, and the peak positions linearly shifted according to the relative content of the urushiol and laccol components in the natural lacquers. This evaluation method was applicable for estimating the mixing compositions of laccol and urushiol in commercially available natural lacquer products. A quantitative analysis of the physicochemical properties of various lacquer films with urushiol, laccol, and their mixtures confirmed that the hardening speed, mechanical hardness, adhesion, and corrosion resistance deteriorated, whereas the transparency and haze properties improved as the laccol content increased. This study suggests that the estimation and optimization of laccol and urushiol compositions in natural lacquers are an important strategy for improving the physicochemical properties of natural lacquer films and extending their applications in various functional coatings.