Characterization and application of citrus pectin composite film containing rosemary (Rosmarinus officinalis L.) essential oil for improving storage of chilled beef

BACKGROUNDThis study used single-factor experiments and response surface methodology to optimize ultrasound time (10-50 min), particle size (0-80 mesh) and extraction time (60-180 min) for the ultrasound-assisted extraction of rosemary essential oil (REO). The resulting REO (0-2.5%, w/w) was then incorporated into citrus pectin (CP) to prepare CP/REO composite films before determining their microstructure, mechanical, barrier and antioxidant properties, alongside their ability to improve the shelf life of chilled beef.RESULTSA sonication time of 41 min, a crushing degree of 40 mesh and an extraction time of 135 min were optimum for extracting 1.91% of REO, with the essential oil also showing good antioxidant activity. Characterization of the composite film further revealed that CP had an excellent film-forming ability and that REO was uniformly distributed in the pectin matrix through hydrogen bonding. The film displayed optimum mechanical and barrier properties at an REO concentration of 1.5% which also significantly enhanced antioxidant activity. Furthermore, the CP/1.5 REO film reduced the total viable count, delayed oxidative rancidity and maintained good color during beef storage, thereby extending the latter's shelf life by 6 days.CONCLUSIONThe novel food packaging film could successfully maintain the quality of chilled meat. (c) 2024 Society of Chemical Industry.