Preparation of microporous starch by glucoamylase and ultrasound

摘要

Microporous starch was prepared from corn starch by glucoamylase catalysis combined with ultrasonic treatment. Twenty milliliters of starch slurries (40, 60, and 80% w/w) were treated with 0.05% v/v glucoamylase (enzyme activity >100 000 U/g), or a combination of 0.05% v/v glucoamylase with ultrasound at 100 W (20% power), 200 W (40% power), and 300 W (60% power) for 10,30, and 50 min concurrently or sequentially. Degree of hydrolysis and degree of oil absorption were applied as indexes to evaluate the quality of the microporous starch. The microstructures, crystalline structures, and pasting properties of microporous starch were studied by SEM, XRD, and rapid visco analyzer (RVA), respectively. The results indicated that the preferred combination was sonication at 200 W (40% power) for 50 min during glucoamylase digestion with 40% slurry concentration. The results of this study provide an efficient method for microporous starch production.