Spray-drying was used to produce the high emissivity NiCr2O4 powders with a spinel structure. Preliminary investigations focused on fabricating the high emissivity powders for infrared radiation coatings and finding t...Spray-drying was used to produce the high emissivity NiCr2O4 powders with a spinel structure. Preliminary investigations focused on fabricating the high emissivity powders for infrared radiation coatings and finding the relationship between microstructure and emissivity. The NiCr2O4 powders were characterized for composition, microstructure, and infrared emissivity by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, infrared radiant instrument, and Fourier transform infrared spectra （FT-IR）. Thermogravimetry and differential thermal analysis show that the appropriate baking temperature for NiCr2O4 powder preparation is about 1200？C. The emissivity measurement and FT-IR spectra show that, because of the special spinel structure, the NiCr2O4 powders have a high emissivity about 0.91. Spray-drying is a suitable method to produce the high emissivity ceramic powders.展开更多
Protein powders from Eisenia foetida were prepared using different drying processes and fractionation. Differential scanning calorimetry was used to show that heat denaturation occurred during the drying process above...Protein powders from Eisenia foetida were prepared using different drying processes and fractionation. Differential scanning calorimetry was used to show that heat denaturation occurred during the drying process above 42°C. Protein solubility was also studied. The addition of dissociating reagents allowed concluding that solubility was decreased during oven drying due to thermo denaturation including hydrogen bonds. The volatile compounds of the different powders were extracted by solid phase micro-extraction and identified by mass spectrometry. Volatile compounds were related to lipid oxidation and Maillard reactions occurring during the preparation of the powders. High drying temperatures led to more volatile compounds resulting from Maillard reactions. In the protein powder preparation process, a fractionation step led to a “pulp fraction” and a “juice fraction” of earthworms. The “pulp fraction” contained less odorant volatile compounds resulting from Maillard reactions than the “juice fraction” did.展开更多
利用响应面法优化南瓜淮山复合固体饮料的喷雾干燥工艺参数,为其工业化生产提供理论依据。以南瓜、淮山为原料,采用喷雾干燥技术制备复合固体饮料,以出粉率为指标,在单因素试验的基础上采用Box-Behnken软件优化喷雾干燥工艺参数。喷雾...利用响应面法优化南瓜淮山复合固体饮料的喷雾干燥工艺参数,为其工业化生产提供理论依据。以南瓜、淮山为原料,采用喷雾干燥技术制备复合固体饮料,以出粉率为指标,在单因素试验的基础上采用Box-Behnken软件优化喷雾干燥工艺参数。喷雾干燥的最佳干燥工艺:乳清分离蛋白(whey protein isolate,WPI)添加量14.6%、进风温度168℃、可溶性固形物5.5%、物料流速9 mL/min,在此条件下出粉率可达52.1%。产品呈细腻均匀粉末,色泽淡黄无杂质,具有南瓜和淮山的香甜。展开更多
文摘Spray-drying was used to produce the high emissivity NiCr2O4 powders with a spinel structure. Preliminary investigations focused on fabricating the high emissivity powders for infrared radiation coatings and finding the relationship between microstructure and emissivity. The NiCr2O4 powders were characterized for composition, microstructure, and infrared emissivity by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, infrared radiant instrument, and Fourier transform infrared spectra （FT-IR）. Thermogravimetry and differential thermal analysis show that the appropriate baking temperature for NiCr2O4 powder preparation is about 1200？C. The emissivity measurement and FT-IR spectra show that, because of the special spinel structure, the NiCr2O4 powders have a high emissivity about 0.91. Spray-drying is a suitable method to produce the high emissivity ceramic powders.
文摘Protein powders from Eisenia foetida were prepared using different drying processes and fractionation. Differential scanning calorimetry was used to show that heat denaturation occurred during the drying process above 42°C. Protein solubility was also studied. The addition of dissociating reagents allowed concluding that solubility was decreased during oven drying due to thermo denaturation including hydrogen bonds. The volatile compounds of the different powders were extracted by solid phase micro-extraction and identified by mass spectrometry. Volatile compounds were related to lipid oxidation and Maillard reactions occurring during the preparation of the powders. High drying temperatures led to more volatile compounds resulting from Maillard reactions. In the protein powder preparation process, a fractionation step led to a “pulp fraction” and a “juice fraction” of earthworms. The “pulp fraction” contained less odorant volatile compounds resulting from Maillard reactions than the “juice fraction” did.
文摘利用响应面法优化南瓜淮山复合固体饮料的喷雾干燥工艺参数,为其工业化生产提供理论依据。以南瓜、淮山为原料,采用喷雾干燥技术制备复合固体饮料,以出粉率为指标,在单因素试验的基础上采用Box-Behnken软件优化喷雾干燥工艺参数。喷雾干燥的最佳干燥工艺:乳清分离蛋白(whey protein isolate,WPI)添加量14.6%、进风温度168℃、可溶性固形物5.5%、物料流速9 mL/min,在此条件下出粉率可达52.1%。产品呈细腻均匀粉末,色泽淡黄无杂质,具有南瓜和淮山的香甜。
