Gelatin-chitosan-pectin films incorporated with rosemary essential oil: Optimized formulation using mixture design and response surface methodology.

The aim of this study was to optimize the mechanical and texture properties of edible film improving its antibacterial property after adding rosemary essential oil (REO) using a Doehlert matrix. Films with the highest mechanical properties were acquired using a polymer composition of 65.2% glycerol, 24.3% gelatin, 10.0% chitosan and 0.5% pectin. This composition provided the highest elongation at break, tensile strength and texture values, which were respectively 51.60 ± 6.04%, 8.53 ± 2.36 MPa and 13.67 ± 1.43. The antibacterial activity of REO enriched films against Bacillus subtilis, Staphylococcus aureus, Enterococcus aerogenes, Enterococcus faecalis and Escherichia coli was enhanced when applying a mixture of 1.995 and 1.250 mg/g of two REO extracted from two rosemary different varieties. The structural, optical and barrier properties of the films were evaluated. To conclude, the enriched film showed potential coatings for controlling most common food borne bacteria growth during the food storage.