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
采用固相微萃取-气相色谱-质谱联用技术对酸水解玉米蛋白粉中的挥发性物质进行分析,并优化固相微萃取条件。结果表明,最优固相微萃取条件为:65μm聚二甲基硅氧烷/二乙基苯萃取头、2.0 g酸水解玉米蛋白粉、5 m L纯水、2.0 g氯化钠置于萃...采用固相微萃取-气相色谱-质谱联用技术对酸水解玉米蛋白粉中的挥发性物质进行分析,并优化固相微萃取条件。结果表明,最优固相微萃取条件为:65μm聚二甲基硅氧烷/二乙基苯萃取头、2.0 g酸水解玉米蛋白粉、5 m L纯水、2.0 g氯化钠置于萃取瓶中,萃取温度60℃、萃取时间30 min。采用气相色谱-质谱联用仪对样品中挥发性物质进行鉴定,共分离出50种化合物,其中醛类、芳香族类、含硫类、有机酸类、吡嗪类、呋喃类、吡咯类对风味贡献较大。展开更多
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.
