The effect of free and encapsulated essential oil and extract of cinnamon with nanoliposome on Listeria monocytogenes and Escherichia coli inoculated into ground beef

The cinnamon essential oil and extract nanoliposomes were prepared through thin layer hydration-ultrasonication technique, using lecithin and three different co-surfactants namely, glycerol, triacetin and propylene glycol, and Tween 80 as surfactant. Results showed that the propylene glycol led to production of the nanoliposomes with the smallest mean particle size (92.03 nm) with spherical-shaped and the greatest net-zeta potential value (-24.1 mV) and was selected as more suitable cosurfactant. Although antibacterial activity of cinnamon essential oil and extract were greater than those were encapsulated into nanoliposomes, both cinnamon essential oil and extract nanoliposomes exhibited high antibacterial activities against Escherichia coli and Listeria monocytogenes bacteria strains. Results indicated that based on the minimum inhibitory and bactericidal concentrations of the prepared samples, L. monocytogenes had higher resistance to the prepared cinnamon nanoliposomes. Then, six treatments including control, extract, nano-extract, essential oil, nano-essential oil and extract- essential oil were used for investigate the effect of cinnamon extract on shelf life of ground beef. Chemical (pH, TBA and TVN) and microbial parameters were detected periodically, as well as the effect of different treatments on ground beef inoculated with Escherichia coli and Listeria monocytogenes were examined. The results showed that the extract has an antimicrobial and antioxidant properties and the nanoencapsulation process enhances the attributes mentioned, so that bacterial spoilage and oxidation process delayed in the ground meet contains nano-extract (p <0.05). The highest value of pH (6.58), TBA (0.081MDA/kg) and TVB-N (72.5mg/100g) in the control treatment on the 9th day was observed. While, the value of pH (6.09), TBA (0.002MDA/kg) and TVB-N (11.5mg/100g) was detected on the 9th day in the nanoencapsulated essence. According to the results obtained in present study nano-liposomal cinnamon extract can be used for extending shelf-life ground beef without causing undesirable effect in terms of oxidative stability and low microbial spoilage.