Abstract: Porous starch, a new type of modified starch with hollow, can be produced by hydrolyzing various raw starcheswith enzymes which can act on them at the temperature lower than that needs for starch gelatinization. It can be widely used in many Industries as a new kind of sorbent with high efficiency, innocuity and safety, including food, pharmacyeutical, agricultural, cosmetic, paper making and other industry. In this paper, the changes of granule structure and properties of native starch by enzymatic hydrolysis are discussed. It can supply theoretical foundation for industrialized production and broadening application range of porous starch. The remaining starch granules after enzymatic hydrolysis were analyzed specific surface area and aperture distributing by specific surface area analyser, the microstructure by scanning electron microscopy(SEM), the crystallinity by X-ray diffraction and the thermal-stability by DSC. The results show BET specific surface area, specific pore volume and distributing aperture diameter of porous starch are increased compared with native starch, porous starch granule looks like honeycomb, porous density is homogeneous, the crystallinity increases and the range of gelatinisation temperature narrows, but the change of endothermic enthalpy is not salience. The granule structure and properties of sustained releasing carrier — porous starch are changed through enzymatic hydrolysis of raw starches at the temperature lower than that needs for starch gelatinization.

Key words:  , porous starch； specific surface area； granule morphology； crystallinity； heat enthalpy property；