微波间歇干燥对玉米籽粒中淀粉理化特性的影响

Effects of Microwave Intermittent Drying on Physicochemical Properties of Starchin Corn Kernels

为提高玉米干燥的速率,明确微波间歇干燥对玉米中淀粉的影响,以"吉农玉719"为研究对象,对比自然干燥和不同微波功率密度条件下微波间歇干燥对玉米中淀粉加工和结构特性的影响。结果表明:与自然干燥的玉米相比,玉米经微波干燥,其淀粉的性质发生明显变化,微波功率密度在0.9~3.6 W/g范围内,玉米淀粉的峰值黏度和溶解度均呈先升高后降低的趋势,当微波功率密度为1.8 W/g时,淀粉的峰值黏度最高,溶解度最高。静态流变学结果表明:玉米经自然干燥和微波干燥,其淀粉凝胶均为假塑性流体。动态流变学结果表明:微波功率密度在0.9~1.8 W/g范围,微波作用可明显改善玉米淀粉凝胶的黏弹性,当微波功率密度为1.8 W/g时,淀粉凝胶的黏弹性最好;当微波功率密度高于1.8 W/g时,玉米淀粉凝胶的硬度显著增加;玉米经微波干燥,其淀粉的膨胀度、热焓值和有序度均降低,粒径增加。结论:在微波功率密度1.8 W/g、微波时间2 min、缓苏时间4 min条件下干燥得到的玉米淀粉特性最佳。

In order to improve the drying rate of corn and clarify the effect of microwave intermittent drying on the starch in corn,this paper took'Jinongyu 719'as the research object,and compared the effects of natural drying and microwave intermittent drying on the processing and structural properties of corn starch under different microwave power densities.The results showed that compared with natural dried corn,the properties of corn starch changed significantly after microwave drying.When the microwave power density was in the range of 0.9-3.6 W/g,the peak viscosity and solubility of corn starch increased first and then decreased.When the microwave power density was 1.8 W/g,the peak viscosity and solubility of starch were the highest.The results of static rheology showed that the starch gel of corn was pseudoplastic fluid after natural drying and microwave drying.The results of dynamic rheology showed that when the microwave power was in the range of 0.9-1.8 W/g,the viscoelasticity of corn starch gel could be significantly improved by microwave.When the microwave power density was 1.8 W/g,the viscoelasticity of starch gel was the best.When the microwave power density was higher than 1.8 W/g,the hardness of corn starch gel increased significantly.After microwave drying,the swelling degree,enthalpy value and order degree of corn starch decreased,and the particle size increased.The results showed that the characteristics of corn starch dried with microwave power density of 1.8 W/g,microwave action time of 2 min and soaking time of 4 min were the best.