Intelligent and active composite films based on furcellaran: Structural characterization, antioxidant and antimicrobial activities

Intelligent and active films were prepared using furcellaran (FUR). The FUR films were modified with various antibacterial material including natural extracts from green tea (GTE) and yerba mate (YM) and synthesized selenium (SeNPs) and zinc oxide (ZnONPs) nanoparticles. The bionanocomposite films were characterized by X-ray diffraction, SEM, TGA and UV-vis spectroscopy. The structural characteristics confirmed successfully formation of FUR films in the presence of tea extracts and NPs. SEM analysis showed smooth and compact surface morphology for FUR, YM and GTE films. Structure of composite films with NPs becomes less homogeneous, with some aggregations or agglomerates of NPs. The addition of both NPs into the films increases their thermal stability, while the incorporation of ZnONPs and YM increased UV-light barrier properties. Films presented different physical properties depending on the composition of the active compounds. The addition of ZnONPs caused the reduction in solubility of prepared films. On the other side, FUR films with the tea extracts show great antioxidant activity based on the ABTS test (inhibition of 37.3% for YM films and of 67.6% for GTE films). However, the FUR films with SeNPs had the highest antimicrobial activity against S. aureus, MRSA and E.coli, with inhibition zone diameters of 21.8 mm, 26.6 mm and 26.7 mm, respectively. The carp spoilage test was done to evaluate possible application of the films as intelligent packages, and color change indicated the film could be used as a sensor in the food industry. The results indicate that composite films based on FUR can be used as smart packaging showing good antioxidant and antimicrobial properties for food packaging applications.