Effects of the combination of repeated heat-moisture treatment and compound enzymes hydrolysis on the structural and physicochemical properties of porous wheat starch.

Effects of the combination of repeated heat-moisture treatment for two times (2-HMT) and compound enzymes hydrolysis on structural and physicochemical properties of porous wheat starches were investigated. The dual-modification resulted in the formation of more pores on the surface of native starches, as revealed by SEM. Compared with single-modified starch samples, the porous starch samples treated by dual-modification exhibited higher gelatinization temperature, lower gelatinization enthalpy and higher crystallinity, as determined by DSC, FT-IR and XRD. Batch adsorption experiments manifested that the dual-modified starch samples exhibited higher adsorption capacities for water, oil and methylene blue. Moreover, the adsorption behaviors of the porous A-type starch granules with or without 2-HMT fitted Freundlich isotherm model well. Low-temperature nitrogen adsorption results showed that dual modifications greatly increased specific surface area and total pore volume of the starch samples. The present study suggests that the dual-modification is an attractive alternative for preparing porous wheat starches.