Antibacterial And Application Research Of Benzyl Isothiocyanate Extracted From Papaya Seeds

Benzyl isothiocyanate receive much attention because of anticancer and antibacterial activity.However,its application in food industry is limited due to its own drawbacks such as volatilization.In this research,the antibacterial activity of benzyl isothiocyanate extracted from papaya seed was analyzed.The benzyl isothiocyanate was encapsulated,the properties of microcapsules were studied,and the preliminary application of microcapsules was researched.This achievement can lay the foundation of the utilization of benzyl isothiocyanate.Through the antibacterial properties of benzyl isothiocyanate extracted from papaya seeds,the order of the antibacterial effect of benzyl isothiocyanate was in turn:Bacillus subtilis>Staphylococcus aureus>Escherichia coli>Salmonella>Saccharomyces cerevisiae>Pencillium>Aspergillus.The antibacterial effect of gram-positive bacterixum was better than that of gram-negative bacterium,and the antibacterial effect of yeast was better than that of mildew.The effect of antimicrobial effect was influenced by the concentration of benzyl isothiocyanate.The MIC of Escherichia coli was 0.8 ?L/mL,the MIC of Bacillus subtilis was 0.4 ?L/mL,the MIC of Pencillium was 1.5 ?L/mL,and the MIC of Aspergillus was 2.0 pL/mL.The antibacterial effect was not significant when the pH in 4.5-7.5.When the temperature was higher than 80 ?,the inhibition effect was significantly decreased.The persistence of the inhibition was limited own to the inhibitory effect of Bacillus subtilis and Pencillium were significantly decreased after 26h and 46h,respectively.Orthogonal experiment was used to study the preparation of ?-cyclodextrin microcapsules based on single factor experiment and the optimum condition was obtained.The final embedding condition was core material rate 1:2,embedding temperature 40 ?,embedding time 2 h,and ultrasonic power 80 W.And the embedding rate was 86.6%.BBD experiment design and response surface analysis were used to study the preparation of chitosan/?-cyclodextrin microcapsules based on single factor experiment and the optimum condition was obtained.The final embedding condition was adding proportion of BITC before and after 1:1,the stirring speed 800 r/min,chitosan content 1%,emulsifier concentration 0.6%,secondary embedding timing 27 min,secondary embedding temperature 38 ?.And the embedding rate was 81.10%.The characteristics of microcapsules were studied by different methods.DSC and TGA analysis can be used to predict the structure of microcapsules.DSC analysis showed that microcapsule was not a simple mechanical mixture,a certain form of crystal structure.Thermo gravimetric analysis showed that the heat stability promoted after embedding.UV wavelength scanning results showed that the maximum absorption wavelength changed from 249 nm to 243 mm and light absorption value increased by 0.119 after the encapsulation.The obviously different crystal structure was observed by scanning electron microscope.And the results showed that the median diameter of ?-cyclodextrin,chitosan,?-CD microcapsules and chitosan/?-cyclodextrin microcapsules were 1.893 ?m,5.684 ?m,2.891 ?m and 9.810?m,respectively.Antibacterial test of the same concentration of microcapsules for Escherichia coli,Bacillus subtilis and baker's yeast,antibacterial circle diameter of ?-cyclodextrin microcapsules were 16.51 mm,32.64 mm and 14.09 mm,respectively,that of chitosan/?-cyclodextrin microcapsules were 24.21 mm,42.57 mm and 20.63 mm,respectively.The slow-release of microcapsules showed that the effect of humidity on the slow release of chitosan/?-cyclodextrin microcapsules was greater than the temperature,which attributing to the two paragraph of release and effective releasing of core material benzyl isothiocyanate.Preliminary application research showed that benzyl isothiocyanate chitosan/?-cyclodextrin microcapsules could enhance the properties and antiscaling of pig tenderloin effectively.