凝胶-冷冻法制备红薯微孔淀粉工艺的研究

以红薯淀粉为原材料制备红薯微孔淀粉,以红薯微孔淀粉的吸水率和吸油率为指标,探讨并优化凝胶–冷冻法制备红薯微孔淀粉的工艺参数。结果表明,制备红薯微孔淀粉的优化工艺参数为:红薯淀粉乳浓度100g/L、糊化时间40min、冷冻时间39h、糊化温度90℃,此工艺下制备的红薯微孔淀粉吸水率为467.51%、吸油率为76.36%。

柠檬酸应用于凝胶-冷冻法制备微孔淀粉的研究

为提高微孔淀粉的吸附性能,将柠檬酸用于凝胶-冷冻法制备红薯微孔淀粉,通过单因素试验和正交试验优化红薯微孔淀粉制备工艺。结果表明,红薯微孔淀粉制备的最佳工艺为:柠檬酸添加量3%、淀粉乳浓度100 g·L-1、糊化时间30 min、冷藏时间48 h、冷冻时间42 h。在此工艺参数条件下,制得的红薯微孔淀粉吸水率为277.32%、吸油率为68.61%。

Nanocomposite LiFePO_4·Li_3V_2(PO_4)_3/C synthesized by freeze-drying assisted sol-gel method and its magnetic and electrochemical properties

Nano-sized LiFePO_4·Li_3V_2（PO_4）_3/C was synthesized via a sol-gel route combining with freeze-drying. X-ray diffraction results show that this composite mainly consists of olivine Li Fe PO4 and monoclinic Li3 V2（PO4）3 phases with small amounts of V-doped LiFePO_4 and Fe-doped Li_3V_2（PO_4）_3. The magnetic properties of LiFePO_4·Li_3V_2（PO_4）_3/C are significantly different from LiFePO_4/C. Trace quantities of ferromagnetic impurities and Fe_2P are verified in LiFePO_4/C and LiFePO_4·Li_3V_2（PO_4）_3/C by magnetic tests, respectively. LiFePO_4·Li_3 V_2（PO_4）_3/C possesses relatively better rate capacities and cyclic stabilities, especially at high charge-discharge rates.The initial discharge capacities are 136.4 and 130.0 mA h g^（-1）,and the capacity retentions are more than 98% after 100 cycles at 2C and 5C, respectively, remarkably better than those of LiFePO_4/C. The excellent electrochemical performances are ascribed to the mutual doping of V^（3＋）and Fe^（2＋）, complementary advantages of LiFePO_4 and Li_3V_2（PO_4）_3 phases, the residual high-ordered carbon and Fe_2P with outstanding electric conductivity in the nanocomposite.