RESUMO
OBJECTIVE: To investigate the enzymatic hydrolysis characteristics of five medicinal starches, i.e.,waxy corn starch, potato starch, pea starch, wheat starch and common corn starch,using gravitational field flow fractionation (GrFFF) and other technologies. METHODS: Firstly, the enzymatic hydrolysis rates of the five medicinal starches were characterized by GrFFF, and the results of GrFFF were verified by determination of the reducing sugar.Secondly, scanning electron microscopy (SEM) and particle size analyzer were used to characterize the changes of particle morphology and size distribution during amylase hydrolysis. RESULTS: The experiments showed that the enzymatic hydrolysis rates of the five medicinal starches were successively decreased. The former two as well as the latter three reached the maximum enzymatic rate at 6-12 h and 12-24 h, respectively. As the enzymatic hydrolysis time increased, the particle size distribution range became wider and the average size increased. The results of reducing sugar quantitation, SEM and particle size analysis were almost identical to those of GrFFF. CONCLUSION: This study proves that GrFFF is an effective analytical technology to characterize the enzymatic hydrolysis of medicinal starch, which expands the application range of GrFFF and provides useful reference for the application of starch in medicine and food sciences.
RESUMO
OBJECTIVE: To study the large/small granule number ratio, granule morphology, crystal structure, amylopectin and amylose ratio of five kinds of medicinal starches. METHODS: Five kinds of medicinal starches were separated and characterized by self-assembled gravitational field-flow fractionation (GrFFF) instrument and the proportion of large and small starch granules was calculated according to the results. Optical microscopy and scanning electron microscopy were applied to characterize the morphological property of starch. FT-IR and X-ray diffraction were used to obtain the starch crystalline structure and crystallinity. The contents of amylose and amylopectin were determinate by double wavelength method. RESULTS: The large/small granule number ratios of the five kinds of medicinal starches had obvious difference. The size difference was obvious and the shape was different. The change trends of the order and the amorphous structure of different kinds of starches were the same as that of its relative crystallinity; the higher the amylopectin content, the lower the amylopectin/amylopectin was, the better the crystallinity was. CONCLUSION: GrFFF can be used to characterize and separate large and small starch granules, and the results are in agreement with that of other methods.