Background: Active food packaging films with improved properties and strong antimicrobial activity were prepared by blending mixed nanomaterials with different ratio [1:4 (40 mg:160 mg), 3:2 (120 mg: 80 mg), 0:5 (0 mg: 200 mg) and 5:0 (200 mg:0 mg)] of ZnO and kaolin with semolina using a solvent casting method and used for the packaging of low moisture mozzarella cheese to test the effect of packaging on the quality change of the cheese for long-term (up to 72 days) refrigerated storage.
Results: Compared with the neat semolina film, mechanical strength (TS) of the nanocomposite films increased significantly (increase in 21-65%) and water vapor barrier (WVP) and O2 gas barrier (OP) properties decreased significantly (decrease in 43-50% and 60-65%, respectively) depending on the blending ratio of ZnO and kaolin nanoclay. The nanocomposite films also exhibited strong antimicrobial activity against bacteria (E. coli and S. aureus), yeast (C. albicans), and mold (A. niger). The nanocomposite packaging films were effectively prevented the growth of microorganisms (coliforms, total microbial, and fungi) of the cheese during storage at low-temperature and showed microbial growth of less than 2.5 log CFU/g after 72 days of storage compared to the control group, and the quality of the packaged cheese was still acceptable.
Conclusion: The semolina-based nanocomposite films, especially Sem/Z3 K2 film, were effective for packaging of low moisture mozzarella cheese to maintain the physicochemical properties (pH, moisture, and fat content) and quality (color, taste, texture, and overall acceptability) of the cheese as well as preventing microbial growth (coliforms, total microbial, and fungi). © 2018 Society of Chemical Industry.
Keywords: ZnO; antimicrobial; food packaging; kaolin nanoclay; mozzarella cheese; nanocomposite film; semolina.
© 2018 Society of Chemical Industry.