Abstract:  Isoamylase is used to cleave the branching point of amylopectin for preparing starch film and raising its tensile strength. Method of orthogonal test was used to study the reaction conditions for isoamlase to cleave the amylopectin of potato starch, and depicted the relative curves of the reaction time to starch film tensile strength, percent elongation fold resistance , permeability and percent amylose. It offerd the basis for making excellent properties edible starch film.

Key words: Isoamvlase Starch film Amylose