Agar-altered foaming bacterial cellulose with carvacrol for active food packaging applications

Bacterial cellulose (BC) is a biodegradable nanoscale film produced by microorganisms, which possesses great mechanical properties and biocompatibility. In this study, we produced foaming BC (FBC) utilizing foam medium with different concentrations of agar. In addition, carvacrol was loaded into the agar/FBC to establish active packaging material. Evaluation by characterization tests indicated that agar/FBC provided lower crystallinity (59.8%∼71.4%) and a high swelling ability (94.7%∼97.9%) compared to BC (92.2% and 96.1%). The 1.5% agar/FBC with carvacrol group exhibited the significantly highest antimicrobial properties against Escherichia coli and Staphylococcus aureus. Moreover, release measurements showed that greater agar addition contributed to higher protein and carvacrol release extents out of the film. Finally, a sea bass packaging test indicated that carvacrol with 1.5% agar/FBC presented a higher antimicrobial ability against Shewanella putrefaciens, great inhibition of lipid oxidation (67.5%), and a slower spoilage degree (49.8%) which suggested that agar/FBC with carvacrol has potential for active food packaging.