The effect of biodegradable film based on polyvinyl acetate / gelatin containing angelica essential oil on increasing the shelf life of pita bread

The use of biodegradable films containing antimicrobial compounds for packaging is one of the effective methods in reducing environmental pollution and the safety of food products. This study aimed to investigate the effect of biodegradable films based on polyvinyl acetate/gelatin containing Angelica essential oil on increasing the shelf life of pita bread. Films based on polyvinyl acetate and gelatin were mixed with 0/100, 20/80, 40/60, 60/40, 80/20, 100/0 ratios and given Angelica essential oil with a concentration of 1250 µg/ml was added. Antimicrobial and mechanical properties were evaluated during 9 days of storage at 25 °C. The optimal film with the highest antimicrobial properties was selected for packing pita bread and its microbial features were compared with pita bread packed in polyethylene. The highest growth inhibition zone of Aspergillus niger and Penicillium expansum belonged to the biodegradable film of 40% polyvinyl acetate and 60% gelatin. Thus, the film was selected for packaging pita bread. Loads of yeast and mold as well as the total bacteria in pita bread packed in the optimal biodegradable film were significantly less than a pita bread packed in polyethylene. With increasing gelatin and decreasing polyvinyl acetate, water vapor permeability, solubility, water absorption, oxygen permeability, and film thickness were increased. The use of biodegradable films containing antimicrobial compounds can be an effective step in reducing the microbial load and increasing the quality properties of bread during storage.