Preparation and characterization of starch crosslinked with sodium trimetaphosphate and hydrolyzed by enzymes

Crosslinked porous starch samples were produced by first crosslinking corn starch with sodium trimetaphosphate (STMP) and then partially hydrolyzing it with a mixture of α-amylase and glucoamylase. The granule morphology, porosity, swelling power, adsorption capacity, crystalline nature, molecular structure, melting and viscometric properties of these starch samples were measured and analyzed. The results showed that the porous starch which was crosslinked with 6% (w/w) STMP (ScPS-6) possessed remarkable superiority in terms of thermal and shear resistance among all the starch samples tested. The ScPS-6 also had the highest porosity and largest average pore diameter values. The swelling power of crosslinked porous starch was 56.3% lower than that of uncrosslinked porous starch. First order reaction kinetics equation was found to excellently (R2 ≥ 0.99, average error = 6.03%) predict the experimental adsorption kinetics data of methylene blue for the crosslinked porous starch samples.