Effects of starches from different botanical sources and modification methods on physicochemical properties of starch-based edible films.

The effects of starches from different botanical sources (waxy corn, cassava, sweet potato, potato, wheat, and corn) and different commercial modified cassava starches (esterified cassava starch, cross-linked cassava starch, and oxidized cassava starch) on the physicochemical properties of starch-based films prepared by solution casting method were investigated. The mildew resistance test showed that the cassava starch (CAS) film-forming dispersion had the best mildew resistance and all the modified starch film-forming dispersions had less mildew resistance than that of the native starch film-forming dispersion. The color and transparency of the films depended on the plant sources and modification methods of the starch. Fourier transform infrared (FTIR) analysis verified the formation of hydrogen bonds between the starch and plasticizer (glycerol) and possible sites for hydrogen bonds on the starch. The atomic force microscope (AFM) results showed that the surface of all starch films was homogeneous except waxy corn starch (WCS) film, wheat starch (WS) film, and corn starch (CS) film. Mechanical properties and water vapor permeability (WVP) tests suggested that CAS film had the best comprehensive properties in native starches. For modified cassava starches, the comprehensive properties of the cross-linked CAS film were better than those of other modified CAS films.