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关键词： Ultrasound treatment   Okara tofu analogues   Gel properties   Water states   Microstructure  

摘要： The effects of high-intensity ultrasound treatment on the physicochemical characteristics, gelation process, water state, and microstructure of okara tofu analogues were evaluated. Suspensions composed of okara and SPI were treated with ultrasound at different power settings (0, 500, 600, 700, or 800 W) for 20 min, and then, the physicochemical characteristics of the suspensions and okara tofu analogues gelation were determined. After ultrasound treatment at different power settings, the mean particle size of the suspension samples decreased, whereas the surface hydrophobicity and free sulfhydryl group contents of the suspension samples increased. The suspension samples exhibited different gelation behaviors, resulting in distinct water-holding capacities, textural properties, and microstructures in the final treated okara tofu analogues. With increasing ultrasound power from 500 W to 800 W, the water-holding capacity and gel yield of the okara tofu analogues first increased and then decreased. When the ultrasound power was set to 600 W, maximum values of the water-holding capacity and gel yield of 73.95% and 97.48%, respectively, were reached. The textural properties were as follows: hardness, 656.75 g;springiness, 1.203 mm;cohesiveness, 0.435 g mm;gumminess 285.75 g;and chewiness, 343.76. The overall acceptability score increased to the highest. Compared with that of the control sample, the T21 relaxation time of okara tofu analogues decreased to 45.43 ms and its peak area increased to 94.97%;the okara tofu analogues showed a more uniform and denser gel network with filamentous and homogeneous pores;and the okara fibers were embedded more uniformly in the network. Therefore, high-intensity ultrasound changed the microstructure and physicochemical properties of okara fibers and proteins, producing a firm and uniform okara tofu analogues gel network. This study can provide a thorough understanding of the gelling properties of okara tofu analogues.

关键词： bacterial cellulose   fermentation conditions   Kombucha   SEM   TGA  

摘要： The production of bacterial cellulose has been limited due to its high cost and low productivity. Alternative low-cost sources of this biopolymer of high purity and biocompatibility are needed in order to benefit from its enormous potential. Kombucha tea is a trend functional beverage whose production is growing exponentially worldwide, and the bacteria present in this fermented beverage belonging to the genusKomagataeibacterare capable of producing a crystalline biofilm with interesting properties. Obtaining bacterial cellulose from Kombucha tea has already been studied, however several fermentation conditions are being optimized in order to scale-up its production. In this study, we characterized the bacterial cellulose produced from three different Kombucha fermentation conditions. The scanning electron microscopy images revealed the crystalline structure of the biofilms. The energy-dispersive x-ray analysis exhibited the chemical composition of the crystals. The thermogravimetric analysis showed a rate of degradation between 490 and 560 degrees C and the differential scanning calorimetry confirmed the presence of crystalline and amorphous regions in the bacterial cellulose samples. The results suggested that crystalline cellulose could be obtained by varying the fermentation conditions of Kombucha tea.

关键词： Drying technique   edibility characteristic   fruit powder   lactobacillus fermentation   Pyracantha fortuneanafruit  

摘要： In this study, hot air drying (HAD), hot air-/microwave-assisted vacuum drying (HAMAVD) and hot air-assisted microwave drying (HAAMD) were applied to lactic acid-fermentedPyracantha fortuneanafruit (PFF). Influences of different drying methods on fluidity and dispersion, microstructure, hygroscopicity, rehydration, colour change, sourness and energy consumption were investigated. Results showed that HAAMD had the best overall performance on the quality of the PFF powder. HAAMD PFF powder had higher expansion force (1.65 mL g(-1)) and water-holding capacity (2.68 g g(-1)), lower degree of compression (9.09%) and energy consumption, smaller colour change and better taste. Organic acids (mainly malic acids) of all drying powders decreased, but HAAMD and HAMAVD could better improve the acidity characteristics of PFF powders, which may be related to the drying time and the temperature change processes. Consequently, this study can provide references for the utilisation of fresh PFF, the design and commercialisation of PFF-related products.

关键词： Physicochemical properties  

摘要： The current work is focused on the evaluation of oxidative stability, thermal behavior, antioxidant activity, phenolic content, and physicochemical properties of nectarine kernel oil. The antioxidant activity of the oil was remarkably high, that is, IC50 = 95.1 mu g/ml. Thermogravimetric experiments indicated thermal stability of the oil at temperatures up to 261 degrees C, where only 2% mass loss was observed, and the oil decomposition occurred in three main stages. Total phenolic content was found to be 334.5 mg GAE/100 g oil. The extracted oil was highly stable for up to 20.92 hr, as per calculations by the Rancimat method. Gas chromatography analysis demonstrated that the extracted oil consisted mainly of unsaturated fatty acids that formed some 92% wt% of the total content. Among others, the fatty acids were mainly composed of oleic (74.55%) and linoleic acids (16.85%). The extracted oil was characterized. The results highlighted the potentials of the nectarine kernel oil for enriching various pharmaceutical products and human nutrition. Practical applications Nectarine (Prunus persica var. nucipersica) is of high commercial value thanks to its outstanding properties such as oxidative stability, thermal behavior, and antioxidant activity. This investigation's outcomes are beneficial to the research and development activities focused on the commercial-scale processing of nectarine seeds.

关键词： block co‐   polymethacrylates   cationic polyelectrolytes   DNA   gene delivery   polyplexes  

摘要： Physicochemical characteristics and biological performance of polyplexes based on two identical copolymers bearing tertiary amino or quaternary ammonium groups are evaluated and compared. Poly(2-(dimethylamino)ethyl methacrylate)-b-poly(oligo(ethylene glycol) methyl ether methacrylate) block copolymer (PDMAEMA-b-POEGMA) is synthesized by reversible addition fragmentation chain transfer polymerization. The tertiary amines of PDMAEMA are converted to quaternary ammonium groups by quaternization with methyl iodide. The two copolymers spontaneously formed well-defined polyplexes with DNA. The size, zeta potential, molar mass, aggregation number, and morphology of the polyplex particles are determined. The parent PDMAEMA-b-POEGMA exhibits larger buffering capacity, whereas the corresponding quaternized copolymer (QPDMAEMA-b-POEGMA) displays stronger binding affinity to DNA, yielding invariably larger in size and molar mass particles bearing greater number of DNA molecules per particle. Experiments revealed that QPDMAEMA-b-POEGMA is more effective in transfecting pEGFP-N1 than the parent copolymer, attributed to the larger size, molar mass, and DNA cargo, as well as to the effective cellular traffic, which dominated over the enhanced ability for endo-lysosomal escape of PDMAEMA-b-POEGMA.

关键词： Soil biological indicators   Microbial community composition   Carbon substrate utilization   Gamma-hydroxybutiric acid  

摘要： The Araucaria forest is a sub-type of Atlantic Forest and it is critically endangered because of deforestation. Despite significant researchers' attention, little is known about the microbial and functional soil diversity of this ecosystem. Our aim was to assess structural diversity (phospholipid fatty acid;PLFA), functional diversity (Biolog ecoplates) and physicochemical soil properties to identify which indicators are the most sensitive to alterations in the Araucaria ecosystems. Soils of three different areas (disturbed, reforested, and native Araucaria forest soils), in two parks of Southeast Brazil, were collected in contrasting seasons (dry and rainy). Principal components analysis (PCA) showed that fatty acid profiles, Biolog and physicochemical properties in Araucaria forest soils were more dissimilar between the different park geographic locations than by forest disturbance levels. However, discriminant analysis identified several variables with greater power to discriminate among forest disturbance levels (native, disturbed, and reforested) within each season. Reforested soils were lower in pH, Al+3, and base cation content compared to disturbed and native soils. Soils disturbed by recreational and understory deforestation were sandier in texture and elevated in P compared to native and deforested soils. Native soil microbial communities utilized certain Biolog substrates to a greater extent, depending on season, compared to communities of disturbed and reforested soils. The best discriminating variable among native, disturbed, and reforested soils for both seasons was gamma-hydroxybutyric acid consumption, which was positively related to native, and negatively correlated to disturbed and reforested soils. Thus, gamma-hydroxybutyric acid consumption may be a useful indicator to monitor the recovery of reforested and disturbed Araucaria soils in reference to its native state.

关键词： Chitin   Nitrogen adsorption isotherm   Shrimp farming waste   Morphology   Particle technology  

摘要： This research evaluated the treatment and processing of white shrimp (Litopenaeus vannamei)exoskeleton by studying the physicochemical characteristics of the biomaterial viewing evaluate its adequacy as a sorbent. White shrimp shell contains chitin, a biopolymer with sorbent properties, and calcium carbonate, an acidity neutralizing agent, among its principal constituents. The exoskeletons, excluding the head, were treated by proposed low-cost methodology. Elemental chemical characterization was performed by inductively coupled plasma mass spectrometry, identifying two different constituent groups: trace and macro elements. Thermogravimetric analysis indicated a high thermal stability when compared to commercial chitin. The Surface Area and Pore Size and Volume analyses showed a heterogeneous specific surface area, with a mean pore diameter in the range of microporous (phi < 20 angstrom) and mesoporous (20 angstrom < phi < 500 angstrom) predominantly. The particle size, determined by Mastersizer 2000, and the morphology, determined by scanning electron microscopy and energy dispersion X-ray spectroscopy, confirmed the heterogeneity of the processed bioresidue. This characterization indicated the adequacy of the treatment for obtaining from shrimp shells a chitinous biomaterial for potential use as a sorption and neutralization agent once its main constituents (chitin and calcium carbonate) were not modified with the treatment.

关键词： Mango   High hydrostatic pressure   Physicochemical property   Carotenoids   Carotenogenic genes  

摘要： This study evaluated the effect of mild high hydrostatic pressure (HHP, 20-80 MPa/10 min) on the quality of the whole fresh mango during postharvest storage. HHP promoted the capacity of cell wall macromolecules binding water and prevented structural damage of mango tissues during postharvest storage. It reduced the respiration rate and the consumption of sugars and acids, and in most cases increased bioactive substances (vitamin C, total phenolics, flavonoids and carotenoids) and antioxidant activities. Moreover, HHP significantly increased carotenoid biosynthesis at the transcriptional level. The expressions of carotenogenic genes including geranylgeranyl diphosphate synthase (4.7 fold), phytoene synthase (4.66 fold), phytoene desaturase (3.53 fold), zeta-carotene desaturase (2.79 fold) and beta-Ring hydroxylase (2.17 fold) were increased after HHP treatment, while zeaxanthin epoxidase (0.78 fold) transcripts were reduced. As a result, there was the increase of carotenes (1.56-2.00 fold), beta-cryptoxanthin (1.38-2.73 fold) and zeaxanthin (1.42-1.67 fold) and the reduction of antheraxanthin (0.64-0.85 fold) and violaxanthin (0.88-0.90 fold) in HHP-treated samples. HHP is likely a potential technology for modulating physiology and nutritional components (especially carotenoids) of the postharvest fruit.

关键词： bioactive packaging   fresh kiwifruit slice   Konjac gum   L. plantarum   shelf life  

摘要： This study investigates the efficacy of Lactobacillus plantarum strains (L. plantarum LP3, L. plantarum AF1, and L. plantarum LU5) incorporated into a Konjac-based edible coating in order to prevent fungi growth and retain physicochemical characteristics of fresh-cut kiwis kept at 4 degrees C for 5 days. For this purpose, probiotic survivability, fungi counts, decay percentage, color changes, titratable acidity (TA), total soluble solids (TSS), ascorbic acid content, chlorophyll amount, total phenolics, and DPPH radical scavenging of fresh-cut kiwis were evaluated. Results indicated that the population of L. plantarum strains in all treated groups retained at sufficient amounts of probiotic consumption (above 6 and 7 log CFU/g) at the end of the storage period and L. plantarum LP3 had the highest viability in comparison to other strains. The incorporation of L. plantarum in Konjac coatings markedly reduced the amount of decay and color changes and maintained the chlorophyll and ascorbic acid contents of fresh-cut kiwis compared to control samples. After 5 days of storage, total phenol content and the DPPH antiradical activities of coated kiwi slices treated with probiotics were observed about 1.2 and 10.23 g/kg compared to the pure Konjac-coated (0.84 and 7.6 g/kg) and Konjac-uncoated samples (0.44 and 4.1 g/kg), respectively. No significant difference in TSS and TA of various treatments was detected. Coated kiwi slices loaded with probiotics had higher overall acceptability compared to Konjac-coated and control samples. In addition, probiotic treatment significantly reduced mold and yeast counts compared to the control group.

关键词： Fe–   Ce   Synthesis methods   SCR   Catalytic activity  

摘要： The Fe-Ce/Ti catalysts with different molar ratios of Fe and Ce were synthesized by the precipitation method and impregnation method and used for the SCR reaction. BET, XRD, NH3-TPD, XPS, H-2-TPR, UV-Vis, TEM, SEM-EDS mapping techniques were performed to explore the physicochemical properties of catalysts synthesized by different methods. As a result, the catalysts synthesized by precipitation method yields higher catalytic activity than that of the catalysts prepared by the impregnation method. The precipitated catalysts possess larger specific surface areas, higher ratios of Ce3+/Ce4+ and Fe3+/Fe2+ and more surface chemisorbed oxygen, as well as the enhanced surface acid sites and redox ability. Besides these, it holds a high dispersion of active species and more uniform smaller nanoparticles. All mentioned above will result in a higher catalytic performance of catalysts.