Production of biodegradable potato starch films containing Lycium barbarum polysaccharide and investigation of their physicochemical properties

Biodegradable films based on potato starch (POS) modified with Lycium barbarum polysaccharide (LBP) were prepared. The basic characteristics of the films, including thickness, opacity, swelling degree, color and water vapor permeability (WVP), were investigated. Rheometry, spectroscopy and textural analysis techniques were applied to determine the micro- and macro-physicochemical properties of the films. The inclusion of LBP in films led to a substantial reduction in thickness (from 0.16 to 0.11 mm), moisture content (from 15.16 % to 13.72 %), and WVP (from 4.03 ×10⁻⁴ to 2.69 ×10⁻⁴ g·mm·cm⁻²·d⁻¹·kPa⁻¹). The film color indices a* and b* (i.e., red and yellow) increased as the amount of added LBP was increased. No grease penetration occurred in films prepared using 0.4 or 0.6 (%, w/v) LBP, and they displayed excellent UV resistance. Incorporation of LBP significantly improved the thermal stability of potato starch films, and inhibited the swelling of film in alkaline solution. The addition of 0.4 or 0.6 (%, w/v) LBP increased the biocompatibility of films and resulted in a high tensile strength (TS) and elongation at break (EAB). Compost burial tests showed that incorporation of LBP did not disrupt the excellent degradation properties of starch films. These results prove the potential of LBP as a green modification material to improve the properties of potato starch-based films.