脉冲电场对木薯醋酸酯淀粉制备及其性质的影响

以木薯淀粉为原料，以乙酸酐为酯化剂，在不同脉冲电场强度（0 kV/cm、2kV/cm、3 kV/cm、4 kV/cm、5 kV/cm、6 kV/cm、7 kV/cm）、不同有效处理时间（0 ms、3 ms、6 ms、9 ms、12 ms、15 ms）和不同酸酐添加量(4%、6%、8%、10%、12%)下湿法制备醋酸酯淀粉，对乙酰基及取代度进行测定，得出经过脉冲电场处理，木薯醋酸酯淀粉乙酰基含量和取代度都有所提高。乙酸酐添加量为6%，电场强度为4 Kv/cm,有效处理时间为9 ms，样品取代度由0.084提高至0.110，说明脉冲电场处理可以促进酯化反应的进行，提高了酯化反应效率。此外还研究了木薯醋酸酯淀粉糊透明度、溶解度及膨润力、冻融稳定性和淀粉糊黏度性质，并通过红外光谱对产品进行结构表征。结果表明：经过脉冲电场处理，木薯淀粉颗粒均引入了乙酰基团，并提高醋酸淀粉的糊透明度、溶解度和膨润力,提高淀粉糊峰值黏度，而淀粉糊稳定性基本保持不变。
Starch acetate was prepared from cassava starch with acetic anhydride as the esterifying agent by the wet process assisted by pulsed electric field (FET) treatment. The effect of PEF) parameters on the formation of cassava starch acetate was evaluated using different strengths (0, 2, 3, 4, 5, 6, and 7 kV/cm), and treatment durations (0, 3, 6, 9, 12, and 15 ms).The effect of the concentration of acetic anhydride added (4%, 6%, 8%, 10%, and 12%) was also explored. In addition, the properties of cassava starch acetate such as paste transparency, solubility, swelling power, freeze-thaw stability, and viscosity were evaluated. Acetyl content and degree of substitution measurements showed that both were increased after PEF treatment. The degree of substitution increased from 0.084 to 0.110 under the following conditions: 6% added acetic anhydride, 4 kV/cm PEF, and 12 ms of reaction duration, indicating that PEF could facilitate esterification. Infrared spectroscopy was used for structural characterization of cassava starch acetate, which showed that the acetyl group was introduced into the cassava starch molecules and improved paste transparency, solubility, swelling power, and peak viscosity, with no effect on freeze-thaw stability.