酶预处理和酸水解制备糯玉米淀粉纳米晶及其表征

采用糖化酶对糯玉米原淀粉进行预处理，通过X射线衍射(XRD)确定糖化酶预处理的最佳用量，再对酶预处理淀粉进行硫酸酸水解，制备糯玉米淀粉纳米晶，采用傅里叶变换红外光谱（FT-IR）、扫描电子显微镜(SEM)、粒径测量和Zeta电位分析等对淀粉纳米晶进行表征。结果表明，用1000U/(g淀粉)活性的糖化酶对糯玉米原淀粉处理2h，再结合酸水解2天，得到粒径约100nm、分散性好、产率为24.1%的糯玉米淀粉纳米晶；相较于仅硫酸酸水解处理，酶预处理结合酸水解法制备糯玉米淀粉纳米晶的反应时间缩短了3天，产率提高了70.9%，淀粉纳米晶的Zeta电位达-22.3 mV。

Prepared and Characterization of Waxy Corn Starch Nanocrystals by Enzyme Pretreatment and Acid hydrolysis

In this paper,the waxy corn starch was pretreated by glucoamylase, and then hydrolyzed by sulfuric acid to prepare waxy corn starch nanocrystals. the best activity of glucoamylase was determined by X- ray diffraction (XRD). The starch nanocrystals were characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), particle size and Zeta potential analysis.The results showed that waxy corn starch was treated with 1000 u/(g starch) active glucoamylase for 2 h, and then hydrolyzed with acid for 2 days to obtain waxy corn starch nanocrystals with a particle size of about 100 nm,good dispersion and yield of 24.1%; Compared with acid hydrolysis alone, the reaction time of waxy corn starch nanocrystals prepared by enzyme pretreatment combined with acid hydrolysis was shortened by 3 days, the yield was increased by about 70.9%, and the Zeta potential of starch nanocrystals was up to -22.3 mV.