Crosslinked chitosan‐based biocomposite films modified with soy protein isolate

The rigid, brittle, and expensive nature of chitosan‐based film limits its application in food packaging despite its relevant advantages. Soy protein isolate (SPI) can be used to complement chitosan to mitigate these problems. In this study, we investigated the effects of SPI on the tensile strength (TS) and other properties of crosslinked chitosan‐based biocomposite film by analyzing the TS, color change, thermal stability, and durability properties of the resultant films. The chitosan/SPI blended films were also characterized through attenuated total reflectance Fourier transform infrared, X‐ray diffraction, and scanning electron microscopy. Results showed that the elongation at break ( ɛ b ) of chitosan‐based film increased from 34.6% (control) to 83.3% after SPI addition. The thermal stability and homogeneity of the blended films also significantly increased. We also found that color changes that resulted from the introduction of SPI were slight and acceptable, that the durability properties of the blended films were not affected after SPI addition, and hydrogen bonds formed between chitosan and SPI. These findings represent a new potential approach to prepare low‐cost and functional chitosan‐based films by incorporating SPI. POLYM. COMPOS., 39:942–949, 2018. © 2016 Society of Plastics Engineers