Development and characterization of biodegradable nanocomposite films incorporating natural antimicrobial agents for dairy product Ainur

Currently, the environmental issues arising due to pollution with plastic packaging waste in the food industry have turned into a critical problem for developing countries like Kazakhstan. The objective of this study was to create and test the properties of nanocomposite biodegradable films consisting of polylactic acid and starch, loaded with montmorillonite nanoclay and thyme essential oil as a part of the development of dairy packaging films. Films were produced using solvent casting technique at various concentrations of nanoclay (۱, ۳, and ۵ wt%) and thyme essential oil (۲ wt%), and tested for their mechanical, barrier, structural, antimicrobial, and practical properties. It has been found that films with ۵ wt% of nanoclay demonstrated increased tensile strength by ۷۰% (۱۸.۴ to ۳۱.۲ MPa) and decreased water vapor permeability by ۵۰% (۴۲.۸ to ۱۸.۴ g m-۲ day-۱). SEM and XRD analyses demonstrated the appropriate distribution of nanoparticles and increased interlayer distance from ۱.۵۲ to ۱.۸۲ nm. Films with thyme essential oil possessed good antimicrobial effect against Staphylococcus aureus (halo diameter ۱۹.۲ mm) and Escherichia coli (۱۵.۶ mm). According to the experiment conducted in refrigerated conditions of milk package testing, the improved film (NC۳-TO) decreased the total amount of microorganisms to ۶۸.۵ log CFU mL-۱ on the ۲۱st day of storage while ۵۶.۸ log CFU mL-۱ were obtained using traditional polyethylene packages (p < ۰.۰۰۱). Thus, the shelf life increased by seven days. Nanocomposite films designed during this research might be a good replacement for conventional plastics in the Kazakhstan dairy market.

کلیدواژه ها:

Biodegradable nanocomposite ، Dairy packaging ، Thyme essential oil ، Polylactic acid