Physico-mechanical and antioxidant properties of gelatin film from rabbit skin incorporated with rosemary acid

In this paper, the influence of rosemary acid (RosA) on the properties and structure of rabbit skin gelatin film was investigated. Compared to controls, the mechanical properties of the film were improved significantly (p < 0.05) at a RosA concentration of 0.05%. However, the elongation at break of the film decreased with RosA at 0.08%, although its tensile strength was significantly increased (p < 0.05). In addition, the addition of RosA increased the thickness and improved the water resistance and UV barrier properties of gelatin films, but decreased the transparency. The gelatin films with RosA had better thermal stability, and the cross-section had more obvious layers because the side chain carboxyl groups and the phenolic hydroxyl groups on the benzene ring of RosA formed hydrogen bonds with the N-H groups of the gelatin and partial gelatin unfolding occurred as RosA concentrations increased. Furthermore, film with RosA exhibited excellent antioxidant activity. Films incorporated with RosA retarded lipid oxidation during storage of Chinese Bacon.