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关键词： gamma-[Glu]((1 <= n <= 5))-Gln   Frozen dough   Antifreeze activity   Bread  

摘要： This study was the first to examine the effects of gamma-[Glu]((1 <= n <= 5))-Gln (GGP, a taste enhancer;added at 0.5% or 5.0%) on the breadmaking using frozen dough. gamma-[Glu]((1 <= n <= 5))-Gln was produced using the method established in our research center. The addition of GGP at either level increased yeast viability, freezable water content and storage and loss moduli, decreased the free sulfhydryl content of dough during the frozen storage and freeze thaw cycles, and improved the microstructure of frozen dough and texture of the baked bread. The addition of GGP at 0.5% led to a dough having the highest extensibility, and most complete and uniform starch-gluten network, and a baked bread crumb with the lowest hardness, best texture, and most uniform organization. These results indicated that GGP has great potential as a food-derived cryoprotectant/antifreeze agent for the baking industry.

关键词： PUFA   Nanoemulsion   Retention rate   Physicochemical properties   Oxidative stability  

摘要： To solve the stability and oxidation issues of alpha-linolenic acid (ALA), this study focused on developing ALA nanoemulsion system (ALA-NE, oil-in-water) and evaluating the effect of environmental conditions on physical stability and the effect of antioxidants on oxidative stability. The physicochemical properties of nanoemulsions were measured at different conditions, including particle diameter, zeta potential, retention rate and peroxidation value (POV). The particle diameter increased significantly and the retention rate decreased after 25 days storage under the conditions of high temperature and metal ions. However, the influence of ionic strength, pH and light was insignificant. As an antioxidant, Vitamin E was more effective at retarding lipid oxidation of nanoemulsions than that of vitamin C. These results provided reference information in preparing effective and stable ALA-NE systems and enlarging the application fields.

关键词： Caboxymethyl cellulose   Polymer-clay hydrogels   Physico-chemical properties   Drug release   In-vitro cytocompatibility  

摘要： Polymer-clay nanocomposite hydrogel films (PCNCHFs) were prepared from caboxymethyl cellulose, polyvinylpyrrolidone, agar and nanosepiolite clay (0, 0.3, 0.5, 0.7, 0.9 and 1.5% reinforcement) by treating thermally in a simple, rapid, and inexpensive route. The PCNCHFs and its 5-fluorouracil (FU)-loaded composites (PCNCHFs@ FU) were tested for FU release and characterized by FTIR, XRD, FE-SEM, EDX, DSC, and TGA analyses to investigate their structural, morphological, and thermal properties. The nanosepiolite-loaded polymer composites (PCNCHF1 to PCNCHF5) exhibited higher tensile strength than the pristine polymer hydrogel (PCNCHF0);consequently, the thermal properties (glass-and melting-transition) were improved. The PCNCHFs@FU demonstrated prolonged FU release at pH 7.4 for 32 h. The biocompatibility of PCNCHFs was tested against human skin fibroblast (CCDK) cells. The viability of cells exposed to all PCNCHFs was >95% after 72 h of culture. The live/dead assay show the proliferation of fibroblast cells, confirming the biocompatibility of the hydrogels. The pH sensitive PCNCHFs@FU release could be suitable for drug release in cancer therapy, and the developed PCNCHFs may also be useful for tissue engineering, food packaging, and other biological applications. (c) 2021 Elsevier B.V. All rights reserved.

关键词： 幕课   在线课程   物理化学   混合式教学  

摘要： 新冠疫情期间,物理化学课程借助网络和慕课进行了混合教学,通过分析学生在学习中的不足,提出了重视预习并改变预习作业内容,通过增加测验次数以量化平时成绩,了解学生的学习情况并制定相应的学习内容,同时扩充了慕课资源,初步取得了成效。

关键词： 实验数据   处理与分析   微课  

摘要： 物理化学实验数据的处理和分析能够帮助学生加深对物理化学理论知识的理解、学会实验数据的表示方法,继而提高学生从事科学实践探究的能力。采用微课这一新的教学模式进行实验数据处理的教学,能够让学生通过可视化的方式学习实验数据的处理和分析。文章通过“金属相图”这一实验为例,详细讲述了微课在实验数据处理教学中的应用。

关键词： Lignite   Dehydration   Pore structure   Functional group   Oxygen distribution  

摘要： The structural characteristics of dehydrated lignite are crucial for the subsequent re-adsorption thermochemical conversion, but it is challenging in enhancing their relationship for dehydration process and physicochemical structure parameters. Herein, the dehydration characteristics of coal samples at different heating rates and the influence of the particle size and initial weight on the moisture content in lignite were investigated. Subsequently, the carbon-containing chemical bonds, distribution characteristics of the pore structure and oxygencontaining functional groups (OCFGS) in dehydrated lignite were characterized, and the possible mechanism of structural change caused by water removal was proposed. As a result, the fresh lignite at different heating rates exhibited three distinguishable drying stages with increasing dehydration temperature. The initial dehydration stage of lignite is determined to be a constant acceleration of moisture release. The dehydration rate of lignite is closely related to the thickness of the lignite bed in the reactor. Additionally, the relative content of OCFGS on the surface of dehydrated lignite exhibits a gradual decreasing trend. Compared with raw coal, with the extension of the dehydration time, the specific surface area, total pore volume, and average pore diameter in dehydrated coal samples decrease, which has also been verified by XPS, SEM and FT-IR analyses. The fitting calculation of the infrared spectrum curve suggested that the dehydration time plays an important role in the change in the carbon-carbon double bond attributed to the aromatic ring or the carbon atoms in the skeleton vibration of the benzene ring.

关键词： HNO_(3)   Fe(N0_(3))_(3)   Mn(N0_(3))_(2)   Coconut husk activated carbon   Physicochemical property   Modification mechanism  

摘要： Fe-loaded activated carbon(AC)has high surface acidity and more active sites,while manganese-loaded AC has high oxygen *** husk AC modified by Fe-Mn was studied with the aim of revealing the modification ***,HNO_(3)AC was prepared using the nitric acid immersion ***,Fe-Mn/AC was prepared using the Fe(N0_(3))_(3)and Mn(N0_(3))_(2)sequential *** effects of HNO_(3),Fe(N0_(3))_(3),and Mn(N0_(3))_(2)on the pore texture and surface chemical characteristics of carbon materials were examined by scanning electron microscopy,Brunauer-Emmett-Teller(BET)analysis,X-ray diffraction and Fourier-transform infrared *** surface topography,pore structure,active material,and functional groups of AC,HNO_(3)/AC,and Fe-Mn/AC were systematically *** following results were *** surface of HNO_(3)AC has more ditches and air voids;the micropores of HNO_(3)AC are deformed and flattened compared to those of *** surface of Fe-Mn/AC exhibits an accumulation ***_(2)O_(4)and FeMn_(2)O_(4)formed more pore *** and HNO_(3)AC have numerous *** higher loading quantity of Fe-Mn results in bigger specific *** active components of Fe-Mn/AC-1,Fe-Mn/AC-2,Fe-Mn/AC-3,and Fe-Mn/AC-4 are MnFe_(2)O_(4),MnO_(0.43)Fe_(2.57)O_(4),Mn_(3)O_(4),and ot-Fe_(2)O_(3)>*** surface functional groups of AC and HNO_(3)AC are oxygen-containing functional *** effect of Fe-Mn modifying conditions on functional group species is rare;however,Fe/AC has more oxygen-containing functional *** research findings can aid in the desulfurization and denitrification of the Fe-Mn/AC catalyst.

关键词： 混合式教学   物理化学   教学改革  

摘要： 在培养“一流应用型人才”的背景下,对物理化学教学模式进行改革。通过线上线下相结合的混合教学模式,引入问题驱动、小组探讨、案例分析、翻转课堂等课堂改革措施,激发学生在学习过程中的积极主动性,培养解决实际问题的能力,并构建学生的科学思维方式及创新意识。

关键词： Mealworm's cuticles   Enzymatic deproteinization   Tenebrio moloitor   Biopolymer  

摘要： As an alternative, cuticles from edible insects was proposed as an unconventional but viable source of chitin and chitosan. The chitin present in the mealworm's (Tenebrio molitor) cuticles was obtained biotechnologically in one step of enzymatic deproteinization and after deacetylated. Differences in the physicochemical characteristics and the properties of the cuticles, chitin, and chitosan were investigated in this study. Commercial chitosan was used as a reference sample to validate the methods used. The enzymatic deproteinization used to obtain chitin showed an efficiency of 85%. The global yield of the process (cuticle-to-chitosan) was 31.9%. The characterization results of these polymers using DSC, FT-IR, XRD, TGA, and SEM techniques demonstrate consistency with the degree of deacetylation of the obtained chitosan, allowing the differentiation between chitin and chitosan. This study suggests that the wastes of edible insect breeding should be collected and evaluated as an alternative of chitin/ chitosan source.

关键词： Sonication   Osmosonication   Vacuum-assisted osmosonication   Ghanaian garlic   Quality parameters  

摘要： This work aimed to assess the impact of sonication (US), osmosonication (US + OD) and vacuum-assisted osmosonication (V + US + OD) pretreatments on the quality of Ghanaian garlic prior to relative humidity convective drying. Hence, slices of fresh garlic subjected to US, US + OD and V + US + OD pretreatments were dried and the following assessed: antioxidant activities, total phenolic content (TPC), total flavonoid content (TFC), polyphenol oxidase (PPO) enzyme inactivation, rehydration ratio (RR), drying kinetics, energy consumption, chromatographic fingerprinting, allicin content and Fourier-transform infrared (FT-IR) spectroscopy. V + US + OD pretreatment gave the best results for antioxidant activities, TPC, TFC, RR and PPO enzyme inactivation. It also recorded the shortest drying time and was more energy efficient. Finally V + US + OD pretreatment maintained the chemical integrity of the finished product and recorded the highest content of allicin. A general trend was however observed for all quality parameters assessed for the various pretreatment methods as: V + US + OD > US + OD > US.