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关键词： CO2 co-feeding syngas   Surfactant assisted co-precipitation   MgO promoted CuZn   Methanol  

摘要： CO2 co-feeding syngas conversion to sustainable fuels and valuable chemicals is one of the promising strategies for partial CO2 abatement. Surface modifications of Mg promoted CuZn based catalysts via one pot non-ionic surfactant assisted co-precipitation route is an effective approach to facilitate the efficient CO/CO2 hydrogenation to methanol. Herein, the influence of different surfactant/(CuZnMg) molar ratios on physicochemical properties and in selective methanol promotion was systematically investigated. The mesostructured CuZnMg (I-III) catalysts with varied molar ratios (0-0.06) led to difference in specific surface area, crystallite size, interaction between the lattices and density of basic sites. For the optimized catalyst CuZnMg (III) (molar ratio = 0.06), the CuO crystallite size, specific surface area and basic sites density was 7.2 nm, 31.23 m(2)/g and 14.6 mu mol/m(2) respectively. Furthermore, the CuZnMg (III) displayed the highest exposed well dispersed CuO species and having strong interaction between Cu and ZnO lattice, as confirmed by H-2-TPR analysis. Hence, CuZnMg (III) exhibited highest total carbon conversion (33.6%) and maximum methanol selectivity (72.5%) under identical reaction conditions (40 bar, 240 degrees C, 2000 mL/gcat.h). The effect of process parameters on total carbon conversion and methanol selectivity of CuZnMg (III) catalyst was also evidenced. Interestingly, the methanol selectivity and basic sites density correlates linearly with surfactant molar ratios and both were improved by 30% and 16% respectively for CuZnMg (III) catalyst when compared with conventional catalyst, highlighting the potential of surfactant assisted catalyst (CuZnMg (III)) for CO/CO2 hydrogenation reactions. [GRAPHICS] .

关键词： Pancreatic lipase   Green solvent   Rhizopus niveus lipase   Ionic liquid   Choline chloride   Molecular docking simulation   Enzymatic hydrolysis  

摘要： The present study investigates deep eutectic solvents (DESs) as potential media for enzymatic hydrolysis. A series of ternary ammonium and phosphonium-based DESs were prepared at different molar ratios by mixing with aqueous glycerol (85%). The physicochemical properties including surface tension, conductivity, density, and viscosity were measured at a temperature range of 298.15 K - 363.15 K. The eutectic points were highly influenced by the variation of temperature. The eutectic point of the choline chloride: glycerol: water (ratio of 1: 2.55: 2.28) and methyltriphenylphosphonium bromide:glycerol:water (ratio of 1: 4.25: 3.75) is 213.4 K and 255.8 K, respectively. The stability of the lipase enzyme isolated from porcine pancreas (PPL) and Rhizopus niveus (RNL) toward hydrolysis in ternary DESs medium was investigated. The PPL showed higher activity compared to the RNL in DESs. Molecular docking simulation of the selected DES with the substrate (p-nitrophenyl palmitate) toward PPL was also reported. It is worth noting that ternary DES systems would be viable lipase activators in hydrolysis reactions. (c) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

关键词： Hydrodynamic cavitation   Ultrasonication   High-temperature short-time processing   Cavitational yield   Energy efficiency   Microbial log reduction  

摘要： The effects of high-temperature short time (HTST), ultrasonication (US) and hydrodynamic cavitation (HC) on physicochemical properties, alkaline phosphatase (ALP) activity, microorganism, degree of protein hydrolysis (DPH), color, microstructure and overall particle size of raw milk were studied. The separation index (SI) was also measured during storage of treated milk at 4 +/- 2 degrees C for 12 days. US was carried out at different intensities (200, 300, and 400 W) and time (4, 6, and 8 min) and HC at 4, 6, 8, and 10 psi for 5, 10 and 15 min. It was observed that HC showed 21% energy efficiency (eta) with higher cavitational yield than US which had eta <10%. Microbial log reduction of 2.30 +/- 0.17 TPC and 2.26 +/- 0.17 (YM) was obtained by HTST treatment. And about 0.9 and 0.7 microbial log reduction were observed in HC and US treatment respectively. Initially in non-thermal treatment, ALP activity increases slightly by 1-2% at 4 psi (HC) and 200 W (US), but with further increase in time and intensity, ALP activity decreases. In addition to that, there was an increase in the DPH from 0.716 +/- 0.09% to about 3.608 +/- 0.52 and 3.77 +/- 0.15% in US and HC treated samples respectively. Also, with an increase in time and intensity, number of fat globules increased with a decreased diameter and overall particle size. In non-thermal treatment, except for samples treated at 200 W (US) and 4 psi (HC), no separation was observed during the storage which could be due to reduced size of fat globules (from 6.3 mu m to 3-2.2 mu m).

关键词： Flavonoids  

摘要： The effects of different hydrothermal pretreatments on the physical chemical characteristics and drying kinetics of red rice starch (Oryza sativa L.) were investigated. The hydrothermal pretreatments chosen include the cooking, autoclave, and steam explosion processes. To obtain the starch in powder form, the pastes were dried at a temperature of 50 degrees C with an air speed of 1.0 m/s. The mathematical models (empirical and diffusive) were adjusted to the experimental data. The starches were submitted to extraction yield, color, water binding capacity, and proanthocyanidins. The values for the diffusivity are between 3.08 x 10(-7) and 2.74 x 10(-6) m(2)/min for treatments. The pretreatments of cooking in the grain and autoclave in the starch gave better results than the other studied treatments (formulations), presenting shorter drying time (450 and 510 min) and higher yield (48.60% and 53.54%), respectively. With the application of pretreatments, it is possible to save energy and reduce thermal damage. Novelty impact statement The results obtained in this study reveals the application autoclave pre-treatment in red rice starch effectively saves energy and reduces thermal damage as the drying time is shortened. In addition, the drying process information can be used when designing future new equipments.

关键词： Pyrolysis   Dried distiller?s grains (DDGs)   Physicochemical characterization   Thermogravimetric analysis (TGA)   Kinetics   Activation energy  

摘要： The physicochemical properties of dried distiller?s grains (DDGs) were measured and the pyrolysis kinetics analysis was experimentally investigated by the non-isothermal thermogravimetric analysis (TGA) at four heating rates of 10, 20, 30 and 40 K min-1. The results of proximate and elemental analysis showed that DDGs contained relatively high contents of volatile organic components (VOCs, 89.4 wt.%) and carbon (47.0 wt.%), and a higher value of heat content (20.4 MJ kg-1), compared with some other typical agricultural residues feedstocks. The pyrolysis kinetics of DDGs sample were analyzed using the Friedman isoconversional method. The obtained effective activation energies vary with the degree of conversion: 151.2-176.3 kJ mol- 1 (?: 0.05-0.10, T: 383?506 K), 176.3-206.4 kJ mol-1 (?: 0.10-0.60, T: 506?653 K), 206.4-320.5 kJ mol-1 (?: 0.60-0.95, T: > 653 K), which correspond to the thermal decomposition of hemicellulose, cellulose and part of lignin, and remaining lignin. And the decomposition temperatures of DDGs components shift to lower temperature, compared with those of typical lignocellulosic biomass, which is caused by the presence of high activity degraded enzymes during brewing process. The physicochemical properties and pyrolysis kinetic results have shown that DDGs has great thermochemical conversion potential for bioenergy. We anticipate these findings will contribute to the industrial application of DDGs pyrolysis to produce biofuel or high-value chemicals and materials.

关键词： Cyperus esculentus seed protein   Functional properties   Emulsifying properties   Ultrasonication  

摘要： In this study, the effects of ultrasonication (0, 200, 300, 400, 500 and 600 W) on the intrinsic fluorescence spectra, surface hydrophobicity (H-0), particle size, ultraviolet (UV) spectra, emulsifying properties and solubility properties of Cyperus esculentus seed protein (CEP) solutions were investigated. An increase in ultrasound power significantly improved emulsifying activity and emulsion stability of CEP (P < 0.05). After ultrasonication, the solubility of CEP increased from 41.29% to 67.53%. Various spectral methods, such as the Fourier infrared spectroscopy, fluorescence spectroscopy, and ultraviolet spectroscopy, showed that ultrasonication changes the structure of the CEP protein, expose the water-transporting groups, and improves the hydrophobicity of the surface. The particle size and turbidity of the protein emulsion significantly decreased after ultrasound treatment, indicating that the particles in the protein solution became smaller and more uniformly distributed. The scanning electron microscopy (SEM) confirmed the results, verifying that the protein particle size was dramatically reduced after ultrasound treatment. This study provides a theoretical basis for the application of CEP in food processing.

关键词： Tequila maturation   Kinetic models   Polyphenols extraction   Thermic treatment   Physicochemical characterization of casks  

摘要： The effect of time in the maturation process of Tequila employing two types of casks was studied: A new (labeled as Cask-New) and a medium-toasted cask (15 min at 200 degrees C) (labeled as Cask-MT). For that purpose, the wood used in the casks was characterized physicochemically, and its properties were contrasted with the physicochemical characterization of the beverage throughout the maturation time. To understand the kinetic maturation process, mathematical models were used. The best model that represented the polyphenol (I-280) and flavonoid (I-365) extraction was proposed by Minchev & Minkov. The extraction rate constants were: k(cask-new,I280) = 0.233 month(-1) vs. k(Cask-MT,I280) = 0.560 month(-1), and k(cask-new,I365) = 0.132 month(-1) vs. k(Cask-MT,I365) = 0.383 month(-1), explaining that the extraction process is slower in Cask-MT due to textural characteristics of casks, mainly related to the thermic treatment used in the toasting stage, which collapses the mesoporous structure having mass transfer limitations. The results obtained allow a better description of the maturation process, a fundamental step from a food engineering standpoint. The next step in the research should be to validate the proposed model to improve the final product quality.

关键词： Nanoemulsions   Biopolymer soluble complexes   Rheological behavior   Bioactive compounds   Functional foods  

摘要： The development of carrier systems for antioxidants is a current topic of study, providing protection against deleterious environmental factors and facilitate their efficient incorporation into more complex food systems. Nanoemulsions (NE) made up with natural ingredients may be considered as potential systems where bioactive compounds could be encapsulated. Whey protein hydrolyzate and high methoxyl pectin soluble complex (WPH-HMP) was obtained and used for stabilizing oil-in-water NE loaded with different beta-carotene concentrations (25, 50 and 75 mg.100 g(-1) emulsion). beta-carotene concentration affected the droplet size, stability, encapsulation efficiency, rheological properties, and protective capacity of the NE. Lower beta-carotene concentrations tended to yield NE with smaller average oil droplets sizes, higher encapsulation efficiency, apparent viscosity and viscoelastic moduli, and higher stability against droplet coalescence, creaming velocity and antioxidant activity degradation.

关键词： Powders  

摘要： Formation of 5-hydroxymethyl furfural (HMF) and acetic acid, browning index (BI) and conformational changes in protein structure in infant formula (IF) powders were studied during storage at 25 and 45 degrees C and relative humidity (RH) range of 11-65%. Three powders with nutritional composition representing stages 1 (IF1), 2 (IF2) and 3 (IF3) of IF were studied. HMF formation in IF powders increased with increasing storage temperature and RH;the increase was highest in IF3 samples. BI showed a linear correlation with HMF concentration, irrespective of variation in product composition. Reduction in pH during storage could be associated with acetic acid formation as a result of Maillard reactions;these were also the likely cause of changes in protein conformation during storage, with decreases in alpha-helical structure and increases in beta-sheets and beta-turns observed. Overall, variation in levels of macro-nutrients influenced the degree of change in the commercial IF powders. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： calcination atmosphere   CO oxidation   CO air   crystallite size  

摘要： Nano-Ni1Co1Ox spinel catalysts were prepared via a coprecipitation method, followed by calcination in different atmospheres (air, CO air, N-2, and static air flow) tested CO oxidation in air. The calcination of basic cobalt-nickel precursor in CO air mixture flow (4.5 vol.%) led to the formation of nano-Ni1Co1Ox spinel with highest specific surface area, smallest crystallite size, porous, and well-dispersed oxygen deficient structural defect morphology as revealed by N-2 physiosorption, X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) results. The calcination in air and N-2 flow improved the CO oxidation activity compared to calcination in static air. Though, the greatest activity was achieved with CO air calcined catalyst giving complete CO oxidation at 150 degrees C.