Abstract:

Corn starch was pretreated with hydrolyzed and hydrolyzed with medium-temperature and high-temperature resistant α-amylases to prepare dextrin. The ultrasound treatment conditions were as follows: power 50 W, total treatment time 5－15 min, working time 2－5 s, and intermissive time 20 s. On the basis of the pretreatment, dextrin with different DE values could be obtained by adjusting hydrolysis time or enzyme dose. SEM observation revealed that the surface of starch granules was eroded by ultrasonic treatment and they were broken to different degrees; High-intensity ultrasound notably increased the degradation of amylopectin, which made the molecular weight distribution of dextrin more uniform and reduced the proportion of large molecules.

Key words: corn starch, dextrin, ultrasonic, DE value