Active Coated PLA-PHB Film with Formulations Containing a Commercial Olive Leaf Extract to Improve Quality Preservation of Fresh Pork Burgers

Since fresh meat is often subject to several degradation reactions that decrease its safety and quality until it is considered unacceptable, the release of bioactive compounds into meat products may be a good option to slow down oxidation and extend its shelf-life by a few days. Therefore, this study aimed to test the application on fresh pork burgers of a PLA-PHB film coated with two different coating formulations (methylcellulose, MC and chitosan, CT), both containing a commercial olive leaf extract OL, to evaluate their effect on meat quality preservation. Samples were tested at 0, 2, 5, 7, 9, 12, and 14 days after packing for microbial, chemical, and sensory evaluations. Except for the chitosan-only formulation, all tested formulations (MC, MC+OL and CT+OL) adhered well to the PLA-PHB base without the use of specific treatments. Meat packed with the different coatings maintained a slightly brighter red colour than the control samples and, as a result, deteriorated more slowly. In the evaluation of lipid oxidation, the CT+OL coating showed lower mean values of mg MDA/kg meat, which were significantly different from the other samples, especially on the 7th and 9th day of storage. Moreover, the CT+OL coating showed a slight slowdown in Enterobacteriaceae growth, revealing promising results in maintaining the meat quality longer.