酸醇水解制备玉米淀粉微晶及其性质研究

Study on preparation and properties of corn starch crystallite with acid-alcohol hydrolysis

以玉米淀粉为原料,在酸醇介质中制备淀粉微晶。实验测定了淀粉微晶的水解率,并进行了淀粉颗粒形貌、偏光十字、溶解度及X射线衍射测定。结果表明:在盐酸量1.72%、温度70℃、乙醇浓度65%、淀粉浓度25%和反应6h时制得较理想的淀粉微晶。随着酸醇水解程度的增加,淀粉颗粒形貌逐渐呈片晶状,最终为碎片;颗粒无定形区先水解,内部比较紧密的无定形区域和缺陷结晶结构接着被水解,进而导致颗粒破裂;颗粒部分偏光十字消失,与扫描电镜分析结果一致;晶体形态仍为A型;同一水解率的淀粉,其溶解度均随温度升高而逐渐增加。

Corn starch crystallite was prepared with acid-alcohol hydrolysis.The hydrolysis rate of starch crystallite in the process was detected,the starch granule morphology,polarized light cross,solubility and X-ray diffraction pattern were also investigated.The results showed that the better starch crystallite could be made in the conditions as follows：hydrochloric acid 1.72%,temperature 70℃,6h,25% starch concentration and 65% ethanol concentration.As the degree of acid-alcohol hydrolysis increased,starch granules were gradually chiped into crystal morphology,and became debris finally.The amorphous areas of the starch were firstly hydrolyzed,then the inner close-up of the amorphous regions and vicious crystal structure,resulting in the breakdown of particles.Part of polarized light cross disappeared partly for the starch granule,according with the scanning electron microscopy analysis results.The preparations were also A-typed starch crystallite and its solubility gradually increased with increasing temperature for the same hydrolysis rate of starch.