Antimicrobial edible materials via nano-modifications for food safety applications

Abstract

Edible films from carboxymethyl cellulose (CMC)/starch incorporated with titanium dioxide (TiO2) nanoparticles were developed. The prepared films were characterized by Fourier transforms infrared, X-ray diffraction, transmission electron microscopy, dynamic light scattering, swelling behaviour, and thermal and mechanical properties. Results showed a decrease in the average particle size of TiO2 nanoparticles with increasing irradiation dose up to 30 kGy. The swelling capacity of CMC/starch blends is ordered in the sequence of composition ratio 2:1 > 1:1 > 1:2. The effect of different irradiation doses (2.5, 5, 10, 15, and 20 kGy) and different concentrations of TiO2 (0.5, 1, 1.5, 2, 2.5, and 3 wt%) on the film properties was evaluated. The tensile strength increased gradually, accompanied by a decline in elongation percentage with the increase in the irradiation dose and increase in the TiO2 contents up to 2.5 wt%. The irradiated CMC/starch/TiO2 film showed higher thermal stability than CMC/starch film. Furthermore, the unirradiated and irradiated CMC/starch/TiO2 edible films were applied to fresh strawberries by surface coating. The irradiated film showed a superior effect in prolonging the fruits’ shelf life. The antimicrobial activity of CMC/starch/TiO2 film against Escherichia coli and Staphylococcus aureus was increased by increasing the irradiation dose. In conclusion, CMC/starch/TiO2 edible film exhibited the prerequisite behaviour for potential application in active food packaging.

Keywords

• gamma irradiation
• starch
• carboxymethyl cellulose
• titanium dioxide
• food coating