Nanoencapsulation of Basil (Ocimum basilicum L.) and Echinophora platylobaDC. Essential Oils in Chitosan Nanoparticles: Characterization and Efficacy in Burger Preservation.

Meat and its derivatives are susceptible to lipid and protein oxidation during processing and storage, negatively affecting product quality and stability. Oxidative processes can reduce nutritional value, flavor, texture, and shelf life. In this study, the effects of essential oils of two aromatic herbs [Echinophora platyloba DC. and basil (Ocimum basilicum L.)] and their nanoencapsulation form (synthesized utilizing essential oils in conjunction with chitosan) on the physicochemical characteristics, antioxidant properties, microbial stability, and shelf life of burgers during storage at refrigeration temperatures were investigated. The particle sizes chitosan (without essential oil), chitosan nanocapsules with basil and E. platyloba essential oils were 500, 70.15, and 60.4 nm, respectively. The zeta potential and encapsulation efficiency of chitosan nanocapsules incorporating basil and E. platyloba essential oils were 63.61 and 65.18 mv, and 88.7% and 88.9%, respectively. The polydispersity index (PDI) values for chitosan nanocapsules, chitosan nanocapsules incorporating basil and E. platyloba essential oils were 0.711, 0.291, and 0.283, respectively. PDI of chitosan nanocapsules incorporating essential oils were lower than 0.5, indicating the uniform size distribution and thus the success of the nanoparticle production process. The chitosan nanocapsules with basil and E. platyloba essential oils could significantly enhance total phenolic content and antioxidant properties; however, pH, thiobarbituric acid (TBA) values, color changes, total microbial counts, particularly Staphylococcus aureus, as well as mold, yeast, and psychrotrophic bacterial populations meaningfully decreased. The chitosan nanocapsules with basil and E. platyloba essential oils (1:1) had an effect on reducing the microbial count by 76%, 78%, and 69% at 4, 8, and 12 days of storage period, respectively, compared to the control. The results of principal component analysis (PCA) and hierarchical cluster analysis (HCA) indicated that the nanoencapsulation of essential oils with chitosan could improve antioxidant stability, limit microbial growth, and maintain the physicochemical characteristics of burgers during storage. In conclusion, the incorporation of the E. platyloba and O. basilicum essential oils within nanocapsule structures offers a feasible approach for the development of novel, functional, and nutritionally advantageous products. This approach may also enhance shelf life, attributable to the inherent antimicrobial and antioxidant properties of the essential oils. Further studies are necessary for sensory evaluation of burgers, isolation of secondary metabolites, as well as toxic effects of nanoencapsulated bioactive compound formulations.