Slowly digestible starch is a new - type of functional starch and it has many physiological functions. Maize starch is used as raw material, ultrasonic — enzyme technology isused to prepareslowly digestible starch. The principle was; the pullulanase could debranching the chain of the starch, shortenthe length of the chain inthe starch. At the same time, the ultrasonic was absorbed by the starch milk, shattered the long chain of starch. On the other side, when ultrasonic work with the pullulanase on the starch solution, the action time was shortened andthe speed of enzyme actionwas increased. By controlling the reaction conditions, we get the best preparation of slowly digestible starch. The best condition was; ultrasonic power 300W, the pullulanase quantity 14% , the reaction time 40min at 40t. Three repeated experiments were carried out under the above conditions and the yield of slowly digestible starch was 43. 14%.%缓慢消化淀粉是近年来新兴起的一种新功能性淀粉,具有很好的生理功能特性.该文以玉米淀粉为原料,采用超声波辅助酶法技术联用制备缓慢消化淀粉.其原理为:普鲁兰酶本身对淀粉具有一定的脱支作用,使淀粉链长度变短,而引入的超声波一方面作为一种能量,能够被淀粉乳溶液吸收,震裂长链淀粉分子,另一方面超声波利用其高频率在与普鲁兰酶协同作用降解淀粉的同时,可以使酶解速度增加,缩短酶的作用时间,通过控制反应条件,取得最佳的制备效果.本章研究了超声波功率、所加普鲁兰酶量、反应时间以及反应温度单因素对最终SDS得率的影响,并在此条件下进行了重复性试验,确定其优化的工艺条件.研究结果表明:超声波功率300W,加14％普鲁兰酶,反应时间为40min,反应温度为40C,并在此条件下进行3次重复性试验,SDS得率为43.14％.
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