Study On The Antibacterial Activity Of Main Components From Spices Essential Oil And Their Preservation Effect On Chilled Meat

Spices essential oils are important secondary substances of plant，which havecomplicated chemical compositions. And their main components are closelyassociated with flavor and diverse bioactivity. They have shown good potentialapplication in several ways，such as preservative, antimicrobial activity, antioxidantand so on.In this experiment, eugenol, isoeugenol, cinnamaldehyde, citral, geraniol andcitronellol are selected for the study, with five common meat spoilage organisms andpathogens--Staphylococci aureus, Escherichia coli, Saccharomyces cerevisiae,Aeromonas and B. thermosphacta used as test bacteria. And the antibacterial activityof six main components was determined by the agar diffusion and dilution method. Tomeasure the minimum inhibitory concentration MIC and the minimum bactericidalconcentration MBC of six main components by means of vitro method. In addition,time-kill curves of five organisms and pathogens in different concentrations of themain components were established. Meanwhile, soluble protein content of suspensionculture of Staphylococci aureus was investigated. And the fresh-keeping fluids wereconfected using antibacterial activity of main components. The preservation effects offresh-keeping fluids were studied according to the freshness integrating evaluation ofchilled meat, such as sensory index, total bacterial count, pH value, texture and flavorchanges. Main results show as followed:(1) The six kinds of main component had differently bacteriostatic action forbacteria and microzyme. Among them，the bacteriostatic actions of eugenol andcinnamaldehyde were the best and better, respectively. And cinnamaldehyde had thelowest MIC and MBC，which showed MIC on Staphylococcus aureus at0.25μl/ml. Asto citral and geraniol, MIC on Staphylococcus aureus were at2μl/ml and1μl/mlrespectively. Eugenol showed highest bacteriostatic effect on Escherichia coli amongstrains, which MIC was0.5μl/ml, while isoeugenol presented best effect on Saccharomyces cerevisiae, which MIC was0.5μl/ml. time-kill curves of fiveorganisms and pathogens in different concentrations of the main components showedthat their bacteriostatic actions were obviously increases with time. Furthermore,Staphylococci aureus, Escherichia coli and Saccharomyces cerevisiae exposured tomain components induced a better change than Aeromonas and B. thermosphacta.And soluble protein content of suspension culture of Staphylococci aureus wasinfluenced by main components to a certain extent.(2) The six kinds of main component and eugenol-cinnamaldehyde compoundfresh-keeping fluids, all can effectively reduce the total number of microorganism andpH value, thus can delay spoilage time. And the sensory evaluation showed that thesmell of chilled meat was improved, which had fragrance of essential oils. Hardness,springiness, cohesiveness, gumminess, chewiness and resilience in the treatmentgroups were superior to that in the control group.(3) By using the GC-MS combination instrument and the electronic nose toanalyze the meat samples, eugenol-cinnamaldehyde compound fresh-keeping fluidscould increase the aroma components of meat, but could barely strengthen of aromaintensity. And meat samples didn’t show evident decay during five days.