Composite film based on carboxymethyl cellulose and gellan gum with honokiol-β-cyclodextrin inclusion complex: Characterization and application in strawberry preservation.

The aim of this study is to fabricate a biodegradable film based on carboxymethyl cellulose and gellan gum (CMC/GG) with the honokiol/β-cyclodextrin inclusion complex (HNK/β-CD). The HNK/β-CD was prepared by freeze-drying and its physicochemical properties were investigated. Then HNK/β-CD was added to CMC/GG solution to form CMC/GG honokiol inclusion complex (HIC) composite film by the casting method. The physicochemical properties, antioxidant and antibacterial effects, and strawberry preservation function were investigated. The composite film with 0.18 % inclusion complex (CMC/GG/0.18 % HIC) was found to be the optimal formulation. The film had a tensile strength of 8.20 MPa and an elongation at break of 115.17 % with water vapor permeability of 0.48 g·mm·(cm·h·KPa). The increase of HNK/β-CD content yielded lower optical transmittance and water content of CMC/GG/HIC composite film, while improved the hydrophilicity value. The 2,2-diphenyl-1-picrylhydrazyl radical and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) scavenging capacities of CMC/GG/0.18 % HIC composite film were 80.83 % and 53.10 % respectively. CMC/GG/HIC composite film was bacteriostatic against Staphylococcus aureus and Candida albicans but not against Escherichia coli and Aspergillus niger. Packing strawberries with the optimized composite film can retain the appearance, titratable acidity and vitamin C content of strawberries, which was better than the commercially fresh-keeping film control group. The CMC/GG/HIC composite film overcame the shortcomings of a single material, and gained importance in food packaging applications.