以蜡质大米淀粉为原料,经过β-淀粉酶处理得到不同水解程度的糊精,并对其理化性质进行了研究。研究表明,在实验设定的条件下,控制β-淀粉酶用量为65 U/g不变,处理时间为20 h时淀粉水解率达到最大为56.7%;扫描电镜测试显示,蜡质大米淀粉为多角形的小颗粒,经糊化-酶解后的样品颗粒形貌被破坏,随着水解程度的增加,碎片数量越多;经过β-淀粉酶的水解,淀粉-碘吸附曲线的最高吸收峰位置偏移,样品与碘的吸附能力均低于原淀粉,且随着水解程度增加吸附能力下降;随着水解程度的增加糊精的大分子部分逐渐减少,小分子部分增加;在同一温度下酶解后淀粉样品的溶解度高于原淀粉,膨胀度则相反,随着水解程度和温度的增加溶解度和膨胀度呈增加趋势;酶解后淀粉样品的透明度明显高于原淀粉,但随水解程度的增加透明度下降。

The native waxy rice starch was applied to prepare dextrin with different hydrolysis degrees by using β-amylase at different time,and the physicochemical properties of the dextrin were also investigated.Results showed that starch treated with β-amylase for 20 hours reached the maximum starch hydrolysis rate.The results from Scanning electron microscopy(SEM) showed that all enzyme-treated samples had more irregular fragments without granular structures.The maximum absorbance and iodine binding of enzyme-treated starches were reduced compared with their native starch parents.The position of maximum absorption peak of starch sample shifted obviously as the increasing degree of hydrolysis.With the prolonging time of hydrolysis,macromoleculars were reduced and small molecules were increased.At the same temperature,the solubilities of enzyme treated starchs were higher than that of native starch,which was different from the swelling power.Meanwhile,the solubility and swelling power increased with the increase of hydrolysis degree and the temperature.Compared with native waxy rice starch,the enzyme-treated samples revealed more remarkable improvement on transparency;but which were constantly descending with the hydrolysis degree increasing.