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关键词： Antioxidant emulsifier   Tea polysaccharide conjugates   Chin brick tea   Nanoemulsions   Carotenoids  

摘要： A natural antioxidant emulsifier, tea polysaccharide conjugate (TPC), was isolated from Chin brick tea. The impact of TPC on 0-carotene stability and bioaccessibility in oil-in-water nanoemulsions was assessed. TPC exhibited strong antioxidant activity and could be used to fabricate stable nanoemulsions (d < 140 nm). The extent of lipid digestion was considerably lower for lipid droplets coated by TPC (68%) than Tween 80 (94%) or whey protein isolate (WPI) (89%), probably because TPC formed interfacial layers that hindered the access of lipases to lipids. The chemical stability of 0-carotene in TPC-nanoemulsions was markedly higher than in those formulated with Tween 80 or WPI due to the high antioxidant activity of TPC. The bioaccessibility of 0-carotene (20-30%) was independent of emulsifier type. TPC from Chin brick tea can therefore be used as a dual-purpose functional ingredient in emulsified foods.

关键词： Aerogel microspheres   Chitosan   Polyvinyl alcohol   Physicochemical properties  

摘要： Chitosan/polyvinyl alcohol (CS/PVA) porous aerogel microspheres with stable physicochemical properties were obtained by gelation and freeze-drying process, and modified by adding different content of polyvinyl alcohol (PVA) into the microspheres. The physicochemical properties of porous aerogel microspheres, including porosity, swelling degree, acid-base resistance and compression performance were compared with chitosan (CS) microspheres. The microspheres were characterized by scanning electronic microscopy, Fourier transform infrared spectra, X-ray diffraction and compression test. The results showed that the structure of hybrid aerogel microspheres could be controlled by adjusting the content of PVA. The increase of PVA content reduced the pore size of CS/PVA porous aerogel microspheres, promoted the roughness of the surface and formed more orderly pore distribution. The higher PVA content was, the greater the swelling degree of the CS/PVA porous microspheres was. Adding proper amount of PVA into the CS/PVA microspheres could improve their acid resistance, but reduce their alkali resistance. Furthermore, the porosity of CS/PVA microspheres containing 33.3% PVA was the highest (78.3%) and the best compression strength (0.0505 MPa) when compression depth was 60% of the maximum height.

关键词： Whey protein isolate   Fibrils   Heating time   Conversion   Microstructure   Antioxidant activity  

摘要： Whey protein isolate (WPI) fibrils have great potential for applications in future food manufacture due to their improved properties. However, the evolution of their properties during fibrillization is still not fully understood. Here, we investigate variational characteristics of WPI fibrils during formation process. WPI fibrils with a semiflexible and linear structure were formed and showed high aspect ratio after heat treatment. The conversion, fluorescence intensity and isoelectric point of WPI were increased with heating time. Moreover, the antioxidant activity of WPI was improved after fibrillization and was dependent on heating time. This could be attributed to the structure transformation of protein and the exposed amino acids with sulfur groups or aromatic side chains in the fibrillated system. Our findings move a step forward for a detailed understanding on the dynamical changes of WPI properties during fibrillization, which would provide a guidance for WPI fibril applications and future food technology development.

关键词： Ultra-High Performance Concrete (UHPC)   Crack resistance   Low cement content   Steel fibers   Expansive agent   Physicochemical multi-factor coupling  

摘要： This study attempts to evaluate and regulate the crack resistance of UHPC mainly based on physicochemical multi-factor coupling methods. First of all, the effects of cement content, steel fibers and expansive agent on UHPC crack resistance are studied. Then, the response surface method is further utilized to investigate physicochemical multi-factor coupling effects on UHPC crack resistance. Based on the obtained results, it shows that using low cement content, adding steel fibers and adding expansive agent all can effectively improve crack resistance of UHPC. In particular, the effect of adding steel fibers is the most remarkable. Besides, the coupling effect among the three factors is explored based on response surface method, and the predicted values and actual values are in good agreement. Among them, there is a good interaction between steel fibers and expansive agent for the UHPC crack resistance improvement. Finally, based on the optimized approach proposed in this study, the crack resistance of UHPC can be effectively evaluated and regulated. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Composition   crystallinity   isolation   morphology   polymorph  

摘要： The purpose of this write-up is to discuss the recent developments in the study of the physicochemical and functional properties of legume starches. Legumes are abundantly rich in proteins, polysaccharides, vitamins, and minerals. Starch is the most important polysaccharide in the human diet. The amylose, lipid, ash, and nitrogen content of legume starches vary in the range of 18-52%, 0.1-0.9, 0.0-0.7%, and 0.0-0.3%, respectively. The legume starches are characteristically rich in amylose, display limited swelling power, poor dispersibility in water, and vulnerable to retrogradation. The properties of legume starches reveal that they possess strong bonding chains between its molecules. Due to these strong bonds, legume starches have high gelatinization transition temperatures and enthalpies. Furthermore, the pasting properties are in accordance with this concept. Legume starches differ in granule morphology, gelatinization transition temperatures, and amylose content. There is need for modification of legume starches due to poor functionality such as easy vulnerability to retrogradation and poor processing properties when subjected to extreme of conditions. These shortcomings of legume starches are usually mitigated by annealing, heat-moisture treatment, cross-linking, acid-thinning, oxidation, and acetylation. This review highlighted developments in the isolation, composition, morphology, physicochemical properties, and some aspect of physical and chemical modification of legume starches.

关键词： Reduced graphene oxide   Aspergillus sp.   Antibacterial   Escherichia coli   Staphylococcus aureus   Live/dead viability  

摘要： Graphene-based nanomaterials are rapidly emerging as antimicrobial agents against a range of pathogenic microorganisms. In the present study, we have demonstrated the synthesis of reduced graphene oxide (RGO) using Aspergillus sp. filtrate as a reducing agent. The obtained Aspergillus sp. filtrate-RGO (AF-RGO) was characterized by ultraviolet-visible absorption spectroscopy, dynamic light scattering, X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and atomic force spectroscopy to obtain details about the size, composition, structure, and morphology. The characterization confirmed the reduction of graphene oxide, the restoration of sp(2) conjugation, and the formation of few-layered RGO sheets. The surface charge and stability of the AF-RGO in aqueous media were examined by zeta potential measurements. The thermal stability of AF-RGO was increased significantly due to the restoration of the graphitic sp(2) network. The antibacterial activity of AF-RGO was evaluated using the agar well diffusion method, broth microdilution method, and Live/Dead bacterial viability assay. AF-RGO exhibited good antibacterial activities against pathogenic Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 15 and 30 mg/ml, respectively. Therefore, fungal filtrate-mediated synthesis of RGO is a promising antibacterial carbon nanomaterial for a range of biomedical and nano(bio)technological applications. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

关键词： Polymeric surfactant   Molecular structure   Emulsion   Flow resistance   Ehnaced Oil recovery  

摘要： Polymeric surfactant can simultaneously thicken aquous phase and reduce water-oil interfacial tension (IFT), which makes it present a great application prospect in the oilfield taword enhanced oil recovery (EOR). There are two kinds of polymeric surfactant with different molecular structures are commonly used to realize the salt resistance, thermal endurance and shear resistance. However, the influence of the molecular structure of polymeric surfactant on their properties related on EOR are not well understood. In the work, we synthesized two kinds of polymeric surfactants with different molecular structure which respectively named intermolecular association molecule (IAM) and rigid chain molecule (RCM). Their physico-chemical properties, porous media transportation and EOR are compared with a series of experiments. It is found that the hydrodynamic characteristic sizes and retention of IAM are higher than those of RCM via the membrane filtration test and nuclear magnetic resonance (NMR) scan. These features make IAM have a larger resistance factor and residual resistance factor than RCM and hydrolyzed polyacrylamide (HPAM) in the same viscosity. Compare to HPAM with shear thinning, RCM presents a Newtonian fluid region and IAM presents a shear thickening region when the shear rate is lower than 1 s(-1). The spatial structure of IAM can pack oil drop into its network, which make it easy to form oilin-water-in-oil (O/W/O) emulsions. Moreover, the concentration and water-oil ratio (WOR) rarely affect the stability of IAM emulsions once the intermolecular association generated. The increamental oil recovery factor of IAM is 17.5% after water flooding in the three-layer core flooding experiments with the permeability of 500 mD, 1500 mD and 3000 mD at 55 degrees C, which is higher than that of 14.5% for RCM and 11.4% for HPAM. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

关键词： spiropyran   functional nanoparticles   anticounterfeiting ink   security tag   fluorescence   photochromic  

摘要： Investigation of developed photoactive security inks and anticounterfeiting technologies in recent years indicates significant challenges for future of this research area, such as increase of security, fast responsivity, and facile authentication. Here, amine-functionalized latex nanoparticles were synthesized by emulsion copolymerization of methyl methacrylate (MMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). Size of the latex nanoparticles was increased as a function of poly(dimethylaminoethyl acrylate) (PDMAEMA) contents, and also a decrease of particle size was obtained in response to an increase of temperature from 25 to 70 degrees C, above the lower critical solution temperature (LCST) of PDMAEMA. Surface physical modification of the functional latex nanoparticle with spiropyran photoswitches led to the development of anticounterfeiting nanoinks that have multilevel security and photochromic/fluorescence properties with a higher intensity and also brightness. The photoluminescent nanoinks were made of spiropyran latex nanoparticles and used for printing of the encoded optical security tags on cellulosic papers and banknotes. The results displayed that an increase of the particle size above 100 nm and an increase of the PDMAEMA contents led to a remarkable decrease of printability, fluorescent emission, brightness, intensity of photochromism, and also resolution of the printed security tags. As a significant advantage of the developed security inks, the printed security tags could be authenticated easily and fast upon sunlight irradiation by means of photochromism. The responsivity of encoded tags from the invisible to visible state is immediate upon sunlight irradiation for some seconds, whose intensity of coloration is appropriate and detectable clearly by naked eyes. The security anticounterfeiting inks based on spiropyran with multilevel security have been reported for the first time for applying in printing of encoded security tags on cellulosic pape

关键词： physicochemical properties   musks   novel brominated flame retardants (NBFRs)   organochlorine pesticides (OCPs)   organophosphate esters (OPEs)   polycyclic aromatic hydrocarbons (PAHs)   polybrominated diphenyl ethers (PBDEs)   polychlorinated biphenyls (PCBs)   phthalates   UV filters   vapor pressure   P-L   water solubility   SW   octanol solubility   S-O   octanol-water partition coefficient K-OW   octanol-air partition coefficient K-OA   dimensionless Henry's law constant K-AW   GC-RT method  

摘要： Accurate values of physicochemical properties are essential for screening semivolatile organic compounds for human and environmental hazard and risk. In silico approaches for estimation are widely used, but the accuracy of these and measured values can be difficult to ascertain. Final adjusted values (FAVs) harmonize literature-reported measurements to ensure consistency and minimize uncertainty. We propose a workflow, including a novel Bayesian approach, for estimating FAVs that combines measurements using direct and indirect methods and in silico values. The workflow was applied to 74 compounds across nine classes to generate recommended FAVs (FAV(R)s). Estimates generated by in silico methods (OPERA, COSMOtherm, EPI Suite, SPARC, and polyparameter linear free energy relationships (pp-LFER) models) differed by orders of magnitude for some properties and compounds and performed systematically worse for larger, more polar compounds. COSMOtherm and OPERA generally performed well with low bias although no single in silico method performed best across all compound classes and properties. Indirect measurement methods produced highly accurate and precise estimates compared with direct measurement methods. Our Bayesian method harmonized measured and in silico estimated physicochemical properties without introducing observable biases. We thus recommend use of the FAV(R)s presented here and that the proposed Bayesian workflow be used to generate FAV(R)s for SVOCs beyond those in this study.

关键词： Hazardous solution   Ammonia nitrogen   Chromium   Waste heat   Resources recovery   Material balance and energy analysis  

摘要： An integrated simple physical-chemical method was proposed to realize the comprehensive utilization of valuable resources from vanadium-extracted solution. The hazardous vanadium-extracted solution contains high concentrations of Cr(VI), ammonia nitrogen, sodium salt, and silicic acid. Firstly, a series of operations include reduction-precipitation, calcination, and leaching were used to recover high concentration Cr(VI), and 99.96% of Cr(VI) was recovered as chromium oxide with the purity of 97.24%. Optimum conditions for the reduction pH, amount of sodium sulfite, precipitation pH, and precipitation time were 2.0, 1.2 times theoretical, 7.3, and 15 min, respectively. Secondly, clean ammonia nitrogen recovery through waste heat distillation was realized. And the total recovery efficiency of ammonia nitrogen was 95.6% at pH = 11.0, distillation 50 min with 0.5M sulfuric acid as the absorption liquid. Also, the distillation residue sodium sulfate was concentrated and purified by distillation. Finally, all the resources were separated efficiently and could be reused back into the upstream vanadium extraction process, achieving resource recycling. Moreover, material balance, energy analysis and the flow chart of the near-zero-waste approach for resource recycling from the hazardous vanadium-extracted solution were concluded.