Intelligent and active furcellaran-gelatin films containing green or pu-erh tea extracts: Characterization, antioxidant and antimicrobial potential.

Biodegradable films from furcellaran and gelatin (FUR/GEL) with pu-erh (RTE) and green tea (GTE) water extracts (TEs) were obtained by a casting method. The films were examined in terms of physical properties (thickness, density, water solubility, water content, degree of swelling, color), antioxidant properties (DPPH, ABTS, TPC), antimicrobial properties (Escherichia coli, Staphylococcus aureus, Candida albicans and Henseniaspora uvarum) and mechanical properties (tensile strength, elongation at break). The values of tensile strength (TS) increased from 9.62 to 24.14 or 13.59 MPa after GTE or RTE incorporation, respectively. Parameters of elongation at break were not changed. Higher color parameters: a*, b* and ∆E were observed in biocomposite films with RTE. The FUR/GEL films with GTE and RTE can be used for intelligent food packaging, due to their sensibility of pH changes. Possible interaction between the film matrix and TEs was confirmed using FTIR. The antioxidant properties were significantly enhanced with increasing GTE and RTE concentration reaching 43.92 and 48.94% of DPPH and 15.76 and 14.98% of ABTS radical inhibition, respectively. The microbiological analysis confirmed antimicrobial properties of FUR/GEL with GTE against E.coli and S. aureus (inhibition zones of 16 and 22.5 mm, respectively).