Novel nanoemulsion-loaded hydroxyl propyl methyl cellulose films as bioactive food packaging materials containing Satureja khuzestanica essential oil

Abstract

This study was conducted in response to a gap in the production of hydroxyl propyl methyl cellulose (HPMC) edible films from Satureja khuzestanica essential oil (SKEO) and to survey the preservation effect of natural edible films on the vapor phase. For these purpose varying concentrations of SKEO ranging from 1.25 % (EF1) to 7.5 % (EF5) led to producing different edible films for potential food packaging applications and the physicochemical, mechanical, and antimicrobial properties of edible films were evaluated across solid, liquid, and vapor phases. The incorporation of nanoemulsions into the polymer films led to an increase in thickness and opacity, while the addition of SKEO resulted in reduced water solubility without impacting film density. Notably, the antibacterial efficacy of the films was most pronounced against S. aureus, with a zone of inhibition measuring 41 ± 1 mm for EF5 on solid media. Time killing assays further demonstrated that specific formulations (EF3, EF4, and EF5) were capable of eradicating all microorganisms within 60 min. Moreover, SKEO edible films exhibited significant inhibitory effects against E. coli under refrigeration conditions (4 °C). These results highlighted the effect of herbal edible films in enhancing the functionality of bioactive food packaging technologies.