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  • Intelligent Chitosan/PVA na...
    Koosha, Mojtaba; Hamedi, Sepideh

    Progress in organic coatings, 02/2019, Letnik: 127
    Journal Article

    •Smart packaging Chitosan/PVA film was prepared using anthocyanin as pH indicator.•The presence of bentonite decreased the water vapor permeability of the films.•Addition of black carrot anthocyanins caused to increasing the tensile strength.•Addition of bentonite and anthocyanins improved antibacterial effect of the films. This study investigated the potential of chitosan/PVA films containing black carrot anthocyanins as a natural pH indicator and bentonite as a nano-filler, for intelligent packaging applications. Two series of chitosan/PVA (CP) films, with different concentrations of bentonite (CPB3%, CPB5%) and with a constant concentration of anthocyanin (CPA, CPAB3%, CPAB5%) were prepared by solution casting method. The colorimetric parameter b* showed an increase from 1.0 ± 0.2 for CP films to 2.7 ± 0.2 and 8.8 ± 1.1 for CPB3% and CPB5% films, respectively which indicates that addition of bentonite increases the intensity of yellow color in the nanocomposite films. The presence of anthocyanins caused to shifting of a* values from negative to positive values which indicated the color change of films from greenness to redness. Addition of bentonite reduced the tensile strength from 100.6 for CP film to 86.5 and 67.2 for CPB3% and CPB5% films which was related to the solution intercalation method used for preparation of nanocomposite films. In contrast, addition of anthocyanins increased the tensile strength for CPA, CPAB3% and CPAB5% due to the hydrogen bonding interactions between its OH groups and PVA and chitosan chains. Water vapor permeability (WVP) of the films was decreased from 1.140 (mg.mm/m2.kPa.h) for CP film to 0.5620 and 0.3515 for CPB3% and CPB5% films, respectively. In contrast, anthocyanins caused to increase WVP of the samples compared to the anthocyanin free films. Thermo-gravimetric analysis showed that the films containing bentonite and anthocyanins have a better thermal stability. Finally, CPAB5% showed the highest bacterial growth inhibition against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, respectively 75.20%, 69.95% and 44.38%.