Study On Antibacterial Activity Of Star Anise Essential Oil And Its Application On Cooling Meat’s Preservation

Star anise is a specialty spice of our nation, which is also a common condimentused in meat processing and it has been shown that the star anise essential oil exhibitsa comparably strong anti-bacterial activity. Contemporary research demonstrates thatthe physiologically active constitutes of star anise existed by means of essential oil.Within the perspective of the anti-bacteria of star anise essential oil, this essay studiedthe optimal extraction craft, constitutes’analysis, antibacterial activity, antibacterialmechanism of star anise essential oil, as well as their stabilities of antibacterial effecton meat and antibacterial effect of the star anise essential oil composite preservativeon cooked meat laden in bulk. Major research results are as below:1Optimization of Extraction craft and Analysis of Chemical Composition Staranise essential oil was extracted by steam distiallation method, supercritical CO2extration method and solvent extraction method(alcohol reflux/alcoholsoak),respectively. And these three extraction methods were optimized then.Finally,in the most preferable condition, the yield rate of star anise essential oil reached4.50%,9.19%and34.52%(alcohol reflux)/20.38%(alcohol soak), respectively.Amongwhich the essential oil extracted through supercritical CO2extration method includeda heavy star anise perfume and contained abundant aroma. Solvent extraction methodprovided the highest yield rate, a large number of solvent was required for thismethod, which contributed a waste, through. Given these factors above, we decided toadopt supercritical CO2extraction method into the following experiments. In addition,GC/MS analysis results show-ed that,48kinds of constitutes were detected in the staranise essential oil, and among which the Anethole,4-Methoxy-Benzaldehyde andLimonene Dipentene took up the highest percentage.2Study on the antibacterial activity The relative common type of bacteria, fungusand yeast: E.coli, staphylococcusaureus, Bacillus subtilis, Bacillus cereus,Saccharomyces cerevisiae, Penicillium chrysogenum, Aspergillus niger were choosento research the antibacterial activity of star anise essential oil.Meanwhile, theinfluential factors (concentration, temperature and illumination) on star anise essentialoil’s antibacterial activity was researched.The results displayed that the star aniseessential oil performed comparably strong antibacterial effects on all these six microbes provided.What’s more,the minimum inhibition concentration(MIC) of staranise essential oil onthe six microbes above were,MIC value of E.coli>5.00%；MICvalue of staphylococcus aureus and Saccharomyces cerevisiae=5.00%；MIC value ofBacillus cereus, Bacillus subtilis and Aspergillus niger=2.50%； MIC value ofPenicillium chrysogenum=1.25%.Moreover, the concentration of star anise essentialoil,illumination and heat treatment all influenced the antibacterial activity.3. Study on the antbacterial mechanism E.coli was chose to participant in ourexperiment,the inhibiting effects of star anise essential oil and its major constitutes(Anethole,4-Methoxy-Benzaldehyde and Limonene Dipentene) to E.coli wasstudied.The influence of these four substances on reducing sugar content, proteincontent and electric conductivity were measured.It was found that the MIC value ofall the four substances above to E.coli were all15.6mg/mL. Moreover, star aniseessential oil and its major constitutes (Anethole,4-Methoxy-Benzaldehyde andLimonene Dipentene) all had influence on reducing sugar content,protein content andelectric conductivity of E.coli.4. Study on the stability of antibacterial effects Star anise essential oil obtainedthrough supercritical CO2extraction was added to the meat samples to research itsantibacterial effect and stability.Results had shown that the star anise essential oilassured the meat samples with preferably fine sensory features and exhibitedcomparably sensational antiseptic effect when at the concentration of8.0%; Therestraining capacity of star anise essential oil on microbes somewhat decreased assaved under the temperature of4℃,25℃,35℃for4d,6h and3h,separately.Long-timeheating and illumination resulted in the descent and even loss of activity of star aniseessential oil.5. The antibacterial effect of compound antiseptic Star anise essential oil wascomplicatedly matched with some common used food antiseptic to research the freshretaining effects of these complex preservatives on meat,it had been shown that8.0%star anise essential oil matched with0.01%BHT,8.0%star anise essential oil matchedwith0.5%sucrose fatty acid ester and7.0%star anise essential oil matched with0.02%potassium sorbate according to the volume ratio3:1,1:1and1:1performedbetter effects.