Study On Antibacterial Activity Of Ethyl Lauryl Arginine Ester And Its Application In Preservation Of Yak Sausage

Lauryl arginine ethyl ester(LAE)was a safe and novel antibacterial agent for food preservation.There were some foreign reports about LAE using in various kinds of food as food additive.Yak meat has the characteristics of rich nutritional value,low fat and rich in various amino acids.However,due to the geographical conditions and production technology restrictions,it is easy to breed corrupt microorganisms during processing and storage,resulting in the loss of nutrients,but the application of LAE in the yak fresh meat sausage had not been reported.In this study,the antibacterial activity and antimicrobial mechanism of intracellular and the ability against digestive enzyme hydrolysis of LAE were studied.The preservation effects of LAE alone and in combination with chitosan and nisin in yak sausage were investigated.Different application forms of LAE emulsion and solid lipid particles were constructed to explore the effects of different application forms on the preservation of yak sausage.The specific research contents and results were as follows:(1)The minimum inhibition concentration(MIC)of LAE against G~-bacteria Escherichia coli,Pseudomonas aeruginosa,Salmonella typhimurium,Lemonobacterium muriae,Streptococcus pneumoniae were 32,32,32,64,32?g/m L,respectively.The MIC of LAE against G~+Bacterium bacillus subtilis,Listeria innocua-and Staphylococcus aureus were 16,16,8?g/m L,respectively.Fungi Candida albicans and Aspergillus Niger were 16,32?g/m L,respectively.The gel retardation assasy had demonstrated that LAE could bind to bacterial protein and DNA after pemeating the cytomembrane to kill the microorganism.The ability of LAE against digestive tract enzymes was detected by HPLC,and it was found that the hydrolysis of LAE occured mainly in the small intestine by trypsin.(2)The effects of LAE,chitosan and nisin on indexes such as thiobar bituric acid,total number of bacteria and pH value during storage of yak fresh meat sausage were investigated.A modeling of the CFU-time relationship was carried out to provide a better evaluation of the antibacterial activity of LAE.The overall antibacterial and fresh-keeping ability was as follows:LAE(0.2 g/kg)+Nisin(0.3 g/kg)+CS(5 g/kg)>LAE(0.2 g/kg)+CS(5 g/kg)>LAE(0.2 g/kg)+Nisi n(0.3 g/kg)>LAE(0.3 g/kg)>LAE(0.1 g/kg)>control.The optimal preservation for mula was LAE(0.2 g/kg)+Nisin(0.3 g/kg)+CS(5 g/kg),which had good chroma,low cooking loss and SAP loss rate at the 15th day of storage,and delayed t he arrival time of the maximum growth rate of bacteria by 9.1 days.(3)LAE solid lipid particles and emulsion with different particle sizes were constructed to investigate the effects of different application forms on pH value,water activity,volatile base nitrogen and other indexes during storage of yak fresh meat sausage.During the storage,the preservation effect of the groups of emulsion and SLPs with small particle size were best,and the growth of microorganism in the yak sausage was significantly inhibited.The addition of LAE with different application forms could cause the reduction of sausages juice loss in the process of storage,the retain of sausages'water holding capacity,the improvement of the brightness of the sausages,There was no significant difference in SAP loss between the SLPs and emulsiongroups.In general,the preservation effect of LAE emulsion was better than SLPs.And the smaller the particle size was,the better the preservation effect.The optimal preservation formula was 3000?g/g small particle size emulsion.