The Study On Antibacterial Activity And Application Of Benzyl Isothiocyanate

Benzyl isothiocyanate,a typical isothiocyanate,has excellent biological activities such as bacteriostasis,anti-cancer,anti-inflammatory and so on.In recent years,it has become a research hotspot for its significant biological activities.However,the bioavailability of benzyl isothiocyanate is restricted by its volatility and thermal instability.In this study,the antibacterial activity of benzyl isothiocyanate and its analogues were measured and their structure-activity relationship was studied.Porous starch was used to encapsulate benzyl isothiocyanate,and the properties of the inclusion complex were characterized.The preliminary application of the inclusion complex was studied.Benzyl isothiocyanate and its 4 analogues all had inhibitory effects on the tested strains.The order of the inhibition activity from strong to weak was ethyl isothiocyanate,phenyl isothiocyanate,benzyl isothiocyanate,benzyl isothiocyanate,phenylethyl isothiocyanate.Combined with the chemical structure,we found that the antibacterial activity of benzyl isothiocyanate was attributed to the interaction of isothiocyanate group,methylene group and benzene ring,and the isothiocyanate group had the most decisive effect,followed by the methylene group and the benzene ring.The effects of different structural substances on the metabolic activity and related enzyme activities of bacteria were different.Among them,benzyl isocyanate(without isothiocyanate group)had the most significant effect on metabolic activity,ethyl isothiocyanate(without benzene ring)takes second place,while the benzene ring had inhibition on the metabolic activity and related enzyme activities.The optimum embedding technology of porous starch was obtained.The embedding rate was 88.42%when the ratio of core to material was 1:2 and the embedding condition was 40? for 3 h.The results of scanning electron microscopy,particle size distribution instrument and infrared spectroscopy showed that the formation of the inclusion complex depended on the excellent physical adsorption of porous starch.Benzyl isothiocyanate entered the porous starch or adhered to the porous starch surface without chemical structure changes during the formation process.The results of thermogravimetry showed that the inclusion complex had better thermal stability.The antibacterial experiment of Escherichia coli and Staphylococcus aureus showed that the diameter of the antibacterial circle of the embedding material was 20.43 mm and 21.69 mm,and the antibacterial effect was remarkable.High temperature and high humidity experiments showed that the inclusion complex should be stored up in the cool dry environment.Preliminary application research showed that the inclusion complex can be used as a antibacterial preservative to prolong the storage period of beef.