Effects of α-amylase and glucoamylase on the characterization and function of maize porous starches

To overcome the limited surface area of starch and improve the adsorption capacity of starch, porous starch has been widely produced in various fields. In this study, the different enzyme activities of α-amylase (AM), glucoamylase (GAM), and mixed enzyme (ME) were used to prepare different types of porous maize starch, and the microstructure, particle morphology, adsorption, and gelatinization characteristics of the porous starch were studied. Scanning electron microscopy showed porous structures with diverse pore size distribution and pore area depending on the enzyme type and its activities; AM produced the largest holes, GAM produced the deepest holes, and ME produced large and deep holes. Adsorptive capacity was significantly affected by enzymatic modification being greater influenced by GAM. The porous starches had higher relative crystallinity as deduced from X-ray diffraction and Fourier transform infrared spectroscopy. The MA-treated starch had higher solubility whereas swelling capacity, peak viscosity, final viscosity, breakdown, and setback of both treatments were decreased compared to the native starch. The results indicate porous maize starch can provide different functions according to the action pattern of enzymes. The type of enzyme and its enzyme activity can be used to produce the ideal cavity and pore size starch granules, which expands its application scope.