Abstract
This work aims to evaluate cinnamon and curcuma essential oils as natural preservatives in minced beef meat. Essential oil chemical compositions and antibacterial activities were studied, and their encapsulation was optimized into nano-emulsions based on droplet size and distribution assessments. Selected formulas were further explored for their physical stabilities and antibacterial activities. Then, their effects on minced beef meat preservation were evaluated. Results showed significant differences in the chemical compositions and the efficiency of the tested essential oils, with cinnamon having a significant antibacterial efficacy. Formulation results showed that cinnamon nanoemulsion, encapsulated by 7.5% Tween 80, possessed an 89 nm droplet size, while the droplet diameter of curcuma nanoemulsion, encapsulated by 5% Tween 80, was 151 nm. Antimicrobial results depicted a significantly higher activity in nanoemulsions as compared to essential oils. For instance, the inhibition diameter of cinnamon essential oils against S. aureus was equal to 35 mm, while that of its nanoemulsion reached 40 mm. The meat preservation results showed that both bulk and nanoencapsulated essential oils significantly inhibited bacterial growth, as well as the formation of methemoglobin and lipid oxidation in meat. Thus, this work draws attention to the enhanced preservation effects of essential oils on the processing of minced beef meat as well as the great potential of nanoemulsions as carriers for essential oils in food industry applications.