Development of grapefruit seed extract-loaded poly(ε-caprolactone)/chitosan films for antimicrobial food packaging

In this study, the packaging films were prepared by blending poly(epsilon-caprolactone) (PCL) with chitosan and grapefruit seed extract (GFSE) using extrusion compounding followed by compression molding. Different GFSE/ chitosan ratios (0.5, 1.0, 1.5, 2.0 and 2.5 mL/g) affected the surface morphology, mechanical and antimicrobial properties of the films. Although the addition of GFSE decreased the films' resistance to breakage and stretching, the films retained adequate tensile strength and desirable flexibility for packaging. More notably, PCL/chitosan/ GFSE films were effective against both Escherichia coll. and Pseudomonas aeruginosa and could inhibit the bacterial growth for up to 120 h when GFSE content increased to 0.5 mL/g and 1.0 mL/g, respectively. Packaging application WA using salmon showed that PCL/chitosan/GFSE films were effective to inhibit the growth of E. coll. in salmon during storage. Furthermore, no mold growth was observed on the bread packaged with films containing >= 1.0 mL/g GFSE after 7 days.