Effect of Lipid-soluble rosemary (Rosmarinus Officinalis L.) extract (carnosic acid) on properties of microcrystalline cellulose/corn starch composite films

The development of biodegradable bioactive films is crucial due to the environmental pollution caused by petroleum-based materials and the food spoilage. Microcrystalline cellulose (MCC)/corn starch (CS) composite films containing lipid-soluble rosemary extract (carnosic acid) (RE) (1 %∼7 %, w/w) were prepared and the effect of RE on the structural, physicochemical, antimicrobial and antioxidant properties of MCC/CS composite films was investigated. The incorporation of lower RE content (1 %) promoted the interactions between film components, thus forming a compact and smooth surface and cross structures. The incorporation of RE changed the long-range order structure of MCC/CS composite film, strengthened the intermolecular interaction between film components, and improved thermal stability. The tensile strength increased from 8.35 MPa to 10.53 MPa and the water vapor permeability decreased from 0.63 to 0.58 g.mm.h^-1.m^-2.KPa^-1. Moreover. Antibacterial (Escherichia coli and Staphylococcus aureus) and antioxidant activity were upsurged as RE contents increased. TOPSIS method indicated the MCC/CS-3 % film and MCC/CS-5 % film were the best films. The above results indicated that an effective use of RE as an enhancer and bacteriostatic agent showed a promising application in food packaging.