酶预处理和酸水解制备糯玉米淀粉纳米晶及其表征

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

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1000 U/g活性的糖化酶对糯玉米原淀粉处理2 h,再结合酸水解2 d,得到粒径约100 nm、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 d,产率提高了70.9%,淀粉纳米晶的Zeta电位达-22.3 mV。

In this paper,the waxy corn starch was pretreated byglucoamylase,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 processed 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 and commendable dispersion and yield of 24.1%.The reaction time of waxy corn starch nanocrystals prepared by enzyme pretreatment combined with acid hydrolysis was reduced by 3 days,the yield was increased by about 70.9% compared those treated with acid hydrolysis alone,and the Zeta potential of starch nanocrystals was as high as-22.3 mV.