Study On Antibacterial And Mechanism Of Cinnamon Essential Oil And Its Application In Spiced Beef Preservation

The paper choosed the cinnamon essential oil as antibacterial agent. Study on antibacterial effect of cinnamon essential oil against food spoilage and pathogenic bacteria and influence factors of stability. On this basis, investigated the antibacterial mechanism of cinnamon essential oil, and added cinnamon essential oil in spiced beef to get a centain preservative effect. The results of the study are as follows:1.the main component of the cinnamon essential oil is cinnamic aldehyde byGC-MS analysis, content of 92.4%, is the main volatile substance and bacteriostasis. This paper selected 8 kinds of food spoilage and pathogenic bacteria. In five kinds of bacteria, the antibactial effect of cinnamon essential oil against bacillus subtilis is the most prominent. The inhibition zone of bacillus subtilis is 23.0mm, MIC and MBC value are 0.5 μ 1/mL、 4.0μl/mLrespectively.Cinnamon essential oil has a less sensitive to Escherichia coli.The inhibition zone of Escherichia coli is 13.7mm, MIC value is 4.0μl/mL,MBC is 8.0μl/mL. Cinnamon essential oil exhibited extremely antibacterial activity to yeast and mold. The inhibition zones of yeast and mold reach from 41.1mm to 45.3mm, far more than bacteria.Between cinnamon essential oil and pH, NaCl there are synergistic antibacterial effect. In the acidic environment, antibacterial performance of cinnamon essential oil showed strong, the growth of the tested strains are suppressed completely. When the pH>6, antibacterialeffect decreased after increased with the increased pH. With the increase of concentration of NaCl, inhibition zones of bacteriashowed increase after decrease. The antibacterial effect against yeast and mold was remarkable. When the concentration of NaCl reached 3%, the yeast and mold was completely suppressed. Cinnamon essential oil showed good thermal stability. At 60℃、80℃、100℃、120℃,the inhibition zones of tested strains were no significant differences.With the increased temperature, the inhibition zones decrease trend was not obvious.Cinnamon essential oil has good volatile. In the Patch test, cinnamon essential oil exhibited good antibacterial effect against test strains in an airtight. The number of bacterial colonies in 6 piece of cinnamon essential oil example was largely inhibited. In the mold example, no hyphae can be see after 5days, and accompanied by rich cinnamon essential oil fragrance.2.Bacteria cell morphology、membrane permeability、membrane integrity and metabolic cell activity has been selected to elaborate the antibacterial mechanism.Scanning electron micrograph showing cell surface folds and distortion, loss of the original cell morphology. Cell even swelled when add with high concentration of cinnamon essential oil. Cell membrane permeability affected by cinnamon essential oil, leakage of small molecules, then ion homeostasis collapse.The relative conductivity of cell suspension increased rapidly with increasing concentrations of cinnamon essential oil. Cell membrane integrity destructed lead to release a large number of nucleic acids and proteins, blocked cell growth and reproduction. When the concentration of cinnamon essential oil is MIC and MBC,content of nucleic acids of E.coli suspension increased from 0.017 to 0.263,0.728 respectively. S.aureus of that increased from 0.022 to 0.249 and 0.502, respectively. Under the same condition, the content of protein of E.coli and S.aureus respectively increased from 34.5μg/mL to 145.8μg/mL, 41.4μg/mL to 93.4μg/mL with cinnamon essential oil increased from MIC to MBC. Cinnamon essential oil impacted cell metabolically active by reduced cell membrane potential. Compared to the control group, the mean fluorescence intensity of E.coli and S.aureus decreased 41.49% and 18.54%, respectively with oil at MIC. When added with MBC concentration cinnamon essential oil, the mean fluorescence intensity of two stains decreased by 80.77% and 71.31%.3. The immersion method was used in this paper, we measured the total number of colonies of spiced beef in 5 days. Concentration of cinnamon essential oil ranged from 0.02% to 0.12%. At the result, the growth of microbial of spiced beef immersed by cinnamon essential oil was significantly inhibited. The total number of colonies of 5 days in theessential oil groups is much lower than that of the control group. The greater the concentration of cinnamon essential oil, the more inhibitory effect can be obvious.