Biodegradable film based on lemon peel powder containing xanthan gum and TiO2–Ag nanoparticles: Investigation of physicochemical and antibacterial properties

Abstract

The aim of this study was to prepare a biodegradable film of sour lemon peel waste. The film of lemon peel powder (LPP) was modified with xanthan gum (XG) and TiO2–Ag nanoparticles (LPP/XG/TiO2–Ag). For this purpose, a central composite design was used to investigate the effect of xanthan gum and TiO2–Ag nanoparticles on the physicochemical and structural properties of the produced film. The results showed that the addition of xanthan gum led to an increase in thickness, moisture and index a of the samples and on the other hand a decrease in moisture and index a was observed with the addition of TiO2–Ag. With increasing xanthan gum, index b decreased slightly and with increasing TiO2–Ag, the amount of yellowness increased. With the addition of gum and nanoparticles, the antioxidant properties were slightly increased. With the addition of xanthan gum and TiO2–Ag, tensile strength and Young's modulus of the film significantly increased and the solubility and WVP decreased (P < 0.05). The FT-IR results showed the electrostatic interaction between lemon peel powder, TiO2–Ag and gum. In the SEM images, films containing TiO2–Ag and gum showed a homogeneous film with a granular state. According to the TGA results, the film samples containing gum and TiO2–Ag had better thermal stability than the control sample. The XRD results showed that adding TiO2–Ag and XG to the films reduced crystalline properties of film. Also, the results of antimicrobial activity against E. coli and Staphylococcus aureus showed that XG and TiO2–Ag increased antibacterial activity of film.