Preparation of V-type porous starch by amylase hydrolysis of V-type granular starch in aqueous ethanol solution

In this paper, a novel porous starch with a V-type crystalline structure and high adsorption capacity was obtained by enzymatic hydrolysis of V-type granular starch (VGS) in an aqueous ethanol solution. The effects of different starch concentrations, reaction temperatures, and ethanol concentrations on the microstructure, crystal morphology, crystallinity and adsorption properties of VGS before and after enzymatic hydrolysis were studied, and native normal corn starch (NNCS) and A-type porous starch (APS) prepared by enzymatic hydrolysis of NNCS were used as controls. The results showed that compared with NNCS, VGS was easier to hydrolyze with a higher hydrolysis degree and the corresponding V-type porous starch (VPS) had more and larger pores and thus showed better adsorption performance than APS. Under the same enzymatic hydrolysis time, temperature and rotation speed, VPS prepared with a starch concentration of 20%, reaction temperature of 140 °C and ethanol concentration of 70% showed an irregular spongelike porous structure, highest V-type relative crystallinity of 25.09%, highest oil adsorption capacity of 241.70% and water adsorption capacity of 805.59%. •V-type porous starch (VPS) was prepared by amylase hydrolysis of V-type granular starch (VGS) in aqueous ethanol solution.•VPS prepared under optimal conditions possessed an irregular spongelike porous structure.•VPS with better oil adsorption capacity exhibits higher V-type crystallinity and hydrolysis degree.•Higher proportion of amorphous regions and V-type crystalline structure of VGS made VGS prone to amylase hydrolysis.