Preparation of corn porous starch by acid hydrolysis and its properties.

In this paper, corn porous starch was prepared by acid–based hydrolysis. Effect of main hydrolysis factors, such as temperature, quantity of acid, time and solid concentration, were investigated by single factor test. The optimal conditions for porous starch production were obtained by orthogonal experiment, which were reaction temperature 40℃, acid concentration 10%, reaction time 12 h, and solid concentration 34%. The granule structure and porous forming process of corn porous starch were observed by SEM, and its thermodynamics properties were analyzed by DSC. Comparing with raw corn starch, specific surface, solubility, expansion ratio, specific surface and transparency of corn porous starch were improved evidently by acid hydrolysis. The oil adsorption ratio could be used as the index to evaluate the corn porous starch. Holes on the surface of corn porous starch were found with different size and density. Narrow range of gelatinization temperature of corn porous starch was found and the endothermic enthalpy was little affected.