Production of Biodegradable Film Based on Polylactic Acid, Modified with Lycopene Pigment and TiO2 and Studying Its Physicochemical Properties

Abstract

In this study, a new film based on polylactic acid (PLA) modified with titanium dioxide and lycopene pigment (PLA/TiO2/Lyc) was prepared. To study the effect of titanium dioxide and lycopene pigment on the physicochemical properties of the film, a central composite statistical design was used. The film properties including moisture, thickness, water vapor permeability, antioxidant activity, antimicrobial properties, and color were studied. The SEM, XRD, FT-IR and DSC techniques were used to study film properties. The results showed that moisture content, antioxidant activity, and film thickness was increased and water vapor permeability was decreased significantly with increasing lycopene and titanium dioxide (P < 0.5). Also, with increasing lycopene concentration, the color indices of a*, b* were increased and the lightness of the films was decreased significantly (P < 0.05). The results of antimicrobial activity showed that the addition of titanium dioxide nanoparticles and lycopene pigment caused antimicrobial activity of film against Escherichia coli and Staphylococcus aureus. Surface morphology analysis showed that the titanium dioxide particles (30–100 nm) were dispersed within the film and the lycopene pigment was distributed evenly in the polymer matrix. Lycopene and TiO2 reduced the pores on the polymer surface. The FT-IR results confirmed the interactions between polylactic acid, titanium dioxide and lycopene pigment. XRD showed that both titanium dioxide and lycopene pigment improved the crystalline structure of the poly lactic acid film. DSC results showed that lycopene and titanium dioxide improved the crystalline melting point of the film. The overall results showed that the prepared film can be used as an antimicrobial and antioxidant film with suitable color properties for active and intelligent packaging in food.