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关键词： Extractive yield   Fluorescence   Macroscopy   Microscopy   Physicochemical   Skimmia anquetilia  

摘要： Skimmia anquetilia (Family: Rutaceae) is an aromatic and medicinal plant distributed in west Himalaya. It is widely used in conventional system of medicine. S. anquetilia is used to treat swellings, rheumatism, heal wounds, as an antidote to snake bite and scorpion bite and also in the treatment of fever, cold and headache. Inspite of its tremendous medicinal value, only less information is available on pharmacognostic characterization of S. anquetilia. The present work deals with comparative pharmacognostical and physico-chemical parameters of different parts of S. anquetilia. Plant material was collected from the natural site, fragmented into different parts, shade dried and powdered. The powdered materials were analyzed for various parameters which include organoleptic study, macroscopy, anatomy, powder microscopy, foreign matter analysis, ash values, loss on drying, swelling index, foaming index, pH values, fluorescence analysis and extractive yield. Organoleptic and macroscopic studies revealed that S. anquetilia is a herbaceous perennial with thick and branched root;oblanceolate, simple and coriaceous leaves;solid and glabrous stem;terminal paniculate inflorescence and red and ovoid fruits. Anatomical studies revealed some unique feature such as calcium oxalate crystals in leaves, oil globules in leaves, stem and root The powder microscopy revealed some distinctive characteristics like different trichomes and lignified spiral and pitted vessels in leaf;oil globules, starch granules and lignified pitted vessels in stem;reticulate parenchyma, lignified pitted vessels and prismatic calcium oxalate crystals in root;unicellular trichomes and spherical pollen grains in flowers;oil globules in testa of fruit. Analysis on the pharmacognostic parameters of different parts of S. anquetilia resulted in a valuable data to establish standards for the plant. The present work is the first attempt to provide a comprehensive report on the quality control and standardization pa

关键词： Crystallinity   dysphagia diets   emulsion stability   molecular structure   viscoelasticity   viscosity  

摘要： Although chemical-free production processes of nanofibrillated cellulose (NFC) have been investigated, comparative studies on the effect of chemical and chemical-free processes to produce NFCs are limited. Combined effect of either of these production routes and defibrillation condition has also never been studied. Here, thermally treated NFCs were produced through microfluidisation for 6-12 passes (ANFC6-ANFC12), while TEMPO-oxidised NFC (TONFC) was prepared at six passes. Proportion of nanocellulose, viscosity, GMODIFIER LETTER PRIME and G" values increased with increased microfluidisation pass in the cases of ANFCs. ANFC12 exhibited gel-like behaviour with strongest three-dimensional network structure and required lowest concentration to enhance thin liquid foods into honey-like consistency. TONFC needed to be added by as much as 8.5, 1.3 and 2.3 times the amount of ANFC12 to achieve the same consistency in thickened water, milk and soup, respectively. ANFC12 can also be well used as Pickering emulsifier due to its higher viscosity and gel-like property.

关键词： citric acid   crystallinity   esterification   hydrochloric acid   hydrophobicity   rice  

摘要： Polymers such as starch are promising in the substitution of synthetic polymers in food packaging, but they present some inferior physicochemical properties. The chemical modification of starch can reduce the limitations of these polymers and make them suitable for packaging production. Therefore, the aim of this study is to elaborate, evaluate, and characterize biodegradable films produced from rice starch modified by hydrolysis and esterification processes. Rice starch hydrolyzed with 0.1 and 0.5 M hydrochloric acid (HCl) and rice starch esterified with 2% and 10% citric acid (CA) are used to produce the packages. The films are characterized in terms of their mechanical properties, optical characteristics, structural and thermal properties, water vapor permeability (WVP), water solubility (WS), and hydrophobicity. Films formulated from hydrolyzed starch show an increase in tensile strength (TS) (11.17 MPa) when compared to the control (1.83 MPa). In addition, the films obtained from hydrolyzed starch present lower solubility (15.6%) and higher relative crystallinity (RC) (71.6%) when compared to the control. The films produced by esterified starch show greater surface hydrophobility with a contact angle of 72.6 degrees while the control shows an angle of 45.8 degrees. Based on the above, the esterified and hydrolyzed starches are promising for the development of sustainable packaging.

关键词： DSC   Crystal structure   IR   Raman   Conductivity  

摘要： Thermal analysis confirmed the presence of the phase transition at T = 320 K in the Cs2SeO4 center dot H6TeO6 (CsSeTe) material. The structural study carried out at T = 360 K shows that this compound passes from the monoclinic system with the space group P2(1)/c at room temperature, to the trigonal system with the space group R $(3) over bar $m. At room temperature, the anionic groups are well ordered and stable, whereas after the transition at T = 320 K, the selenate groups change their orientation and the tellurate polyhedra change their positions. The high-temperature vibrational studies, carried out in a temperature range of 289-353 K, confirm the presence and nature of the transition detected by thermal analysis. The conductivity evolution versus temperature shows the presence of an ionic-protonic conduction phase transition at T = 490 K.

关键词： Thermal energy storage   Phase change materials   Encapsulation   Sol-gel   Boron nitride   Shape stability  

摘要： Monolithic shape-stabilized phase change materials (ss-PCMs) are among the most promising materials to store large amounts of solar energy, waste heat and off-peak electricity as heat in energy-saving buildings, battery-and water-heating systems. Generally, graphite-like additives, such as hexagonal boron nitride platelets (BN), are used to increase the thermal conductivity of ss-PCMs. However, it is still unknown which particle size and surface type of graphite-like additives increase the thermal conductivity of ss-PCMs to the highest extent. Here, we present the first experimental study about the influence of BN with different particle sizes and specific surface areas on the physicochemical properties of ss-PCMs synthesized via the sol-gel route. With a BN particle size of 25 mu m, the average thermal conductivity of ss-PCMs containing 5-20 wt% BN increased by 57% when compared to the same ss-PCMs prepared with smaller BN particles (3 mu m). This effect possibly results from the stronger exfoliation of the larger BN particles during synthesis and a larger amount of BN particles ordered in the same alignment in the silica structure. BN particles larger than 25 mu m hinder the formation of mechanically stable silica structures. Smaller BN particles lead to higher viscous reaction mixtures with shorter gelation times and, thus, result in smaller silica macropores with diameters below 1 mu m and higher compressive strengths of ss-PCMs up to 2.4 MPa at 10 degrees C and 1.7 MPa at 30 degrees C. An increasing specific surface area of BN up to 20 m(2)/g decreases the thermal conductivity by 0.11 W/mK (30 degrees C) and the compressive strength by 0.28 MPa (30 degrees C) of ss-PCMs with 20 wt% BN because of more BN agglomeration. Therefore, ss-PCMs containing 20 wt% BN with a particle size of 25 mu m and a specific surface area of 3 m(2)/g have the highest thermal conductivity of 1.14 W/mK at 10 degrees C and 0.62 W/mK at 30 degrees C, but a 0.7-0.3 MPa lower compressive s

关键词： ZSM-12   m-xylene   microwave synthesis   hydrothermal synthesis   isomerization   catalyst  

摘要： The properties of ZSM-12 zeolites prepared under hydrothermal conditions and microwave radiation influence were studied. The prepared zeolites are characterized by a wide range of physicochemical methods of analysis: X-ray diffraction analysis, low-temperature nitrogen adsorption/desorption, scanning electron microscopy, solid-state Al-27 and Si-29 NMR spectroscopy, infrared spectroscopy, temperature-programmed desorption of ammonia, infrared spectroscopy of adsorbed pyridine, and X-ray fluorescence elemental analysis. The calcined zeolites were impregnated with 0.5 wt % Pt, which performs the hydrogenation function in the reaction under study. The obtained materials were studied in the m-xylene isomerization reaction under the following conditions: T = 300-440 degrees C, WHSV = 1 h(-1), P(H-2) = 10 atm. It was found that, on the ZSM-12 MW catalyst, owing to its high acidity and fine particles, which promote high mass transfer, it is possible to increase the yields of m-xylene isomers, in particular p-xylene, to 36-65%.

关键词： Phytoglycogen   Hydrophobic modification   Delivery system   pH-driven   Encapsulation   Curcumin  

摘要： Phytoglycogen (PG), a water-soluble glycogen-like alpha-D-glucan, exists as natural dendritic nanoparticles which are known as a promising solubility enhancer and delivery vehicle for lipophilic compounds. However, the practical applications of PG in food and pharmaceutical fields are limited by their high hydrophilicity and relatively low encapsulation efficiency compared with other delivery systems. The objectives of this work were to chemically modify native PG nanoparticles with hydrophobic groups and to characterize their physicochemical properties, as well as to evaluate the application feasibility of modified PG (mPG) nanoparticles as a carrier for hydrophobic bioactive compounds. The surface hydroxyl groups of PG nanoparticles were capped with various anhydrides, e. g., acetic, valeric, and N-caprylic, to obtain the PG nanoparticles with different hydrophobicity. Successful modification by acyl groups was evidenced by both Fourier-transform infrared and nuclear magnetic resonance spectroscopies. The mPG nanoparticles exhibited a more compact structure and homogeneous size distribution as revealed by dynamic light scattering measurement and visualized by transmission electron microscope, while their size slightly increased with the chain length of anhydride. Rheological measurement revealed that the viscosity of mPG at low shear rate was increased with the increase of degree of substitution due to the intermolecular hydrophobic association. A novel pH-driven method to load curcumin showed significantly higher encapsulation efficiency and greater antioxidant activity compared with traditional ethanol mediated loading method. Hydrophobic modification of natural dendritic PG nanostructures demonstrates promising potential to develop food-grade nanocarriers for lipophilic bioactive compounds with improved bioactivity.

关键词： Optical and Electronic Materials   Characterization and Evaluation of Materials  

摘要： The present study depicts physicochemical characteristics of Gd3+ modified Fe3O4 nanoparticles synthesized via the sol-gel combustion method. Structural, microstructural, optical, electrical, and magnetic characteristics were investigated. X-ray diffraction studies demonstrated that all the compositions exhibit cubic crystallinity and phase pure crystal structure with space group Fd (3) over barm. FESEM micrographs depicted that the average crystallite size increases from 15.35 nm [x = 0] to 23.74 nm [x = 0.10] with increasing Gd3+ content. FTIR spectra of the compositions show bend at 522 cm(-1) belonging to Fe-O stretching, which confirms the formation of ferrite nanoparticles. Photocatalytic activity of Fe(3-x)GdxO4 nanoparticles with x = 0 and 0.10 was carried out using methylene blue (MB) dye under UV light. Dielectric studies revealed that the dielectric constant decreases due to the incorporation of Gd3+ ion in the Fe3O4 crystal lattice. Negligible coercivity and remnant magnetization revealed the superparamagnetic behavior for all the compositions and it was observed that saturation magnetization decreases with increasing Gd3+ concentration. Magnetic recyclability illustrated the reusability of Gd3+ modified Fe3O4 nanoparticles.

关键词： Hibiscus sabdariffa beverages   acceptance   physicochemical characteristics   total soluble polyphenols content   antioxidant activity  

摘要： The calyces of roselle (Hibiscus sabdariffa L.) are used to make a refreshing drink with high content of anthocyanins and other phenolic compounds, although the process for obtaining the beverage is not standardized. In this research it was determined physicochemical characteristics, total soluble polyphenols content, antioxidant activity and acceptance for beverages prepared by decoction at four concentrations of calyces in water (1.0, 2.5, 5.0 and 10.0%) and two concentrations of sucrose (11 and 16%). Color parameters in beverages permitted to describe them as red, which turned darker as the content of hibiscus increased. Total soluble polyphenols content and antioxidant activity were directly correlated with content of calyces in beverages and inversely correlated with pH, which means that beverages with higher content of calyces could be perceived as more acidic and more intense in characteristics associated with hibiscus presence, such as acid, astringent and the presence of intense dark red color, although the higher concentration of sucrose might have contributed to mask slightly the sourness and astringency. Acceptance for hibiscus beverages allowed to observe two segments of consumers, high-intensity and low-intensity likers but both confluence in overall liking values for beverages prepared with 2.5% calyces and 16% sucrose.

关键词： Aqueous enzymatic extraction   Rice bran oil   Quality analysis   Microstructure  

摘要： Rice bran as a by-product of rice processing can be used to produce oil. Aqueous enzymatic extraction (AEE) of rice bran oil (RBO) was performed in this study. The physicochemical properties, fatty acid compositions, bioactive compounds, antioxidant activity and thermal behavior of AEE-extracted oil (AEEO) were evaluated and compared with those of Soxhlet-extracted oil (SEO). It was found that iodine value and saponification value in the AEEO were higher than the SEO. AEEO with lower acid value and peroxide value was considered to be a high quality. The contents of wax and phospholipid in AEEO were lower, which could simplify the refining steps. Additionally, AEEO exhibited a higher content of unsaturated fatty acids (76.31%), sum of tocopherols and tocotrienols (1004 mg/kg), sterols (7749 mg/100 g), squalene (2962 mg/kg), oryzanol (2.43 g/100 g). The antioxidant activity of AEEO (EC50 = 5.52 mg/mL) was better than that of SEO (EC50 = 8.66 mg/mL). Moreover, AEEO was found to have lower crystallization and melting points. Scanning electron microscope (SEM) results showed the destruction of cell walls and the decrease of substances in the cell by AEE. Overall, the present results showed the improvement in the quality of the AEEO for green extraction of RBO.