Sucrose stearate (SS) is an environmentally sound surfactant with a polar head compatible with starch.Different proportions of SS was blended with corn starch or plasticized corn starch with 20% urea.The mixture was pasted with hot water and cast into films.The crystal structure of the films was characterized by using X-ray diffraction

and the moisture adsorption and the tensile performance were tested.The results indicated that SS interacted with amylose to form a V-type inclusion complex and had influences on the B-type crystallization of starch.Therefore the moisture adsorption and the tensile performance of starch films changed with their SS content.The moisture adsorption of the starch film increased upon adding a small amount of SS (say

0.5%)

and then decreased with further increase of the content of SS.After adding SS into the plasticized starch with urea 20 wt%

the crystallinity

crystal size

moisture adsorption and tensile property of the starch films changed with the SS content in a complicated manner.SS and urea showed a synergistic effect of modification on starch materials.The starch film plasticized with 20 wt% urea and combined with 0.5 wt% sucrose stearate showed an amorphous feature of X-ray diffraction and higher elongation at break.