Development of multifunctional bionanocomposite films based on corn starch incorporating roselle extract and TiO2 nanoparticles

Abstract

Abstract The biodegradable and multifunctional nanocomposite films incorporated with TiO2 nanoparticles (T) and roselle extract (RE) in corn starch (CS) matrix were successfully developed by the solution casting method. The physical and functional properties of bionanocomposite films were comparatively evaluated as well as an analysis of the microstructure of films. The properties of CS film could be significantly altered by incorporating TiO2 and/or RE, and the CSRE, CST and CSTRE films all exhibited improved mechanical properties, higher barrier properties against water vapor and UV light. The composite films containing RE also obtained pH sensitive ability, showing color visibly variations to different pH values. The CSTRE film performance 1.52 times higher tensile strength and 27.1% lower water vapor permeability than CS film accompanying enhanced UV light blocking capacity. Scanning electron microscopy (SEM) appeared more compact and homogeneous microstructure in CSRE and CSTRE films compared to CS film and the Fourier transform infrared (FTIR) spectroscopy and X ray diffraction (XRD) results indicated that there were good interactions between TiO2 nanoparticles, RE and starch molecules. Antioxidant and antimicrobial assays revealed that the antioxidant activity of bionanocomposite films were mainly affected by RE and the antimicrobial impression related to both RE and TiO2. The CSTRE film possessed strong antioxidant activity and exhibited obvious antimicrobial activity against S. aureus and E. coli. It suggested that the multifunctional bionanocomposite films incorporated TiO2 nanoparticles and RE with corn starch could be a potential approach for developing sustainable active food packaging.