Abstract
The study aimed to evaluate the quality of the coated freeze-dried chicken meat using gelatin-chitosan film enriched with Tunisian rosemary extract. The quality was evaluated on the basis of physical and barrier properties, as well as lipid oxidation for coated and uncoated chicken meat. Chicken breast meat was cut into small pieces, pasteurized, and coated with the active film solution. The active gelatin-chitosan film enriched was prepared with different concentrations of rosemary extract (0 to 2%). The application of the coating solution, with or without ultrasonic treatment was conducted. Subsequently, the samples were subjected to freeze drying for 72 h. The water activity, color, hygroscopic, and rehydration properties of the freeze-dried coated meat were measured. Moreover, the lipid oxidation of the coated vs. uncoated meat was also investigated during a 6 month storage period. Results showed that the coating can form a non-porous surface, which resists the exchange of water vapor, thereby decreasing hygroscopicity and rehydration rates. Likewise, the reduction in the color change and the level of malondialdehyde proved that the active coating allowed good preservation of the meat samples against lipid oxidation during the storage period. However, the application of coating with the use of ultrasound treatment did not positively affect lipid oxidation reduction, and an even higher value was observed in comparison to samples immersed in film forming solutions without ultrasound treatment. It can be concluded that the phenolic compounds incorporated into the film matrix had antioxidant activity, minimizing the extent of lipid oxidation in foods.