Starch behaviors and mechanical properties of starch blend films with different plasticizers

• Mechanical properties of plasticized starch blend (CSMB) films were non-additive.
• The non-additive effect was more pronounced in the glycerol-plasticized system.
• CSMB films had most of thermal properties close to one of individual (MB) films.
• Plasticized CSMB and MB films had a similar crystallinity type.
• M¯w of amylose of CSMB films was similar to that of MB films but not the content.

The main objective of the study was to gain insight into structural and mechanical starch behaviors of the plasticized starch blend films. Mechanical properties and starch behaviors of cassava (CS)/and mungbean (MB) (50/50, w/w) starch blend films containing glycerol (Gly) or sorbitol (Sor) at 33% weight content were investigated. It was found that tensile strength TS and %E of the Gly-CSMB films were similar to those of MB films; but%E of all Sor-films was identical. TS of plasticized films increased when AM content and crystallinity increased. When Sor was substituted for Gly, crystallinity of starch films and their TS increased. The CSMB and MB films had somewhat a similar molecular profile and comparable mechanical properties. Therefore, it was proposed the starch molecular profile containing amylopectin with high M¯w, low M¯w of amylose, and the small size of intermediates may impart the high TS and%E of starch films.