Effect of addition of pullulan on the properties of native/waxy corn starch-based films

Abstract

This article reports on the preparation of native/waxy corn starch (NCS/WCS)-based films with the addition of pullulan (PUL). Our study investigated the effects of varying amounts of PUL and amylose contents on the structure, mechanical and physicochemical properties of corn starch films. Notably, it was observed that WCS films with low amylose content exhibited superior transparency, while NCS films with high amylose content demonstrated enhanced tensile strength (up to 7.35 ± 0.18 MPa). Fourier transform infrared spectroscopy (FTIR) analysis indicated that the addition of PUL did not change the molecular interactions within the corn starch films. The X-ray diffraction (XRD) results supported that the WCS films were amorphous, while the NCS film exhibited B-type and V-type crystals. Moreover, an increase in PUL content led to a gradual reduction in the crystallinity of both WCS films and NCS films. The addition of PUL improved the mechanical properties and oxygen barrier characteristics of these films but had an adverse impact on their water vapor barrier properties. These findings offer valuable insights for the selection of additives for corn starch film, which can further enhance the practical application potential of corn starch films in food and other industries.