Investigating the Preservative Effect of Edible Coating Based on Chitosan‐Gelatin Containing Satureja bachtiarica and Nepeta binaludensis Essential Oils Nanoemulsions on the Physicochemical, Microbial and Sensory Properties of Burger During Cold Storage

Abstract

ABSTRACT This study investigated the effectiveness of chitosan‐gelatin (CG) based coatings enriched with free and nanoemulsion forms of Satureja bachtiarica (SE) and Nepeta binaludensis (NE) essential oils on the quality of beef burgers during 12‐day refrigerated storage. GC–MS analysis identified 37 and 50 phytochemicals in SE and NE, respectively, with carvacrol and 1,8‐cineole being prominent compounds. The nanoemulsions were characterized by a spherical shape, a size range of 65.6–122.4 nm, low, polydispersity index (0.286–0.391), zeta potential between −26.7 and −38.2 mV, and high encapsulation efficiency (83.96%–85.31%). While nano‐encapsulation slightly reduced total phenol content, it enhanced the essential oils' antimicrobial activity. Over the storage period, the pH, total volatile basic nitrogen (TVB‐N), and microbial load of all burger treatments increased, while L* and a* values decreased. Compared with the control, burgers coated with the SE nanoemulsion exhibited a 52.9% reduction in TVB‐N (14.90 vs. 31.62 mg N/100 g) and a 38.8%, 42.7%, 39.7%, and 57.1% reduction in viable mesophilic bacteria, psychrotrophic bacteria, LAB, and coliform counts, respectively, on day 12. Moreover, the NE nanoemulsion reduced mold and yeast counts by 48.2% compared with the control (2.54 vs. 4.90 log CFU/g). The nanoemulsion forms of the essential oils demonstrated superior antimicrobial efficacy throughout storage, with the SE nanoemulsion‐coated burgers exhibiting the highest activity at the end of the trial. Sensory evaluation confirmed that these active coatings maintained burger acceptability. These findings suggest that CG‐based coatings enriched with SE and NE nanoemulsions are a promising solution for extending the shelf life of beef burgers.