| Tween 80 as an emulsifier,could regulate the osmotic pressure of the cell membrane through emulsification and change the permeability.Leonard-Akkari et al found that tween 80 could inhibit spores germination and growth,however,the antibacterial effect and mechanism of tween 80 combined with HPTS on spores are still unknown.Therefore,HPTS combined with tween 80 treated Bacillus subtilis was comprehensively analyze the effect of tween 80 on spores inactivating by HPTS and the effect of emulsifier in food system,the following studies were mainly carried out.(1)Effect of tween 80 on inactivating Bacillus subtilis spores by HPTSAfter the treatment of 0.5%,1%,2%(v/v)tween 80 combined with HPTS(200 MPa,600 MPa,25℃,65℃,75℃)for 20 min.The effect of tween 80 on the spore inactivating effect of HPTS was comprehensively analyzed by the numbers of spore survival,turbidity(OD600)change of spore suspension,the release of DPA(2,6-pyridine dicarboxylic acid)and conductivity on spores.The results showed that tween 80 could weaken the spore inactivating effect of HPTS,0.5%tween 80 combined with 200 MPa,75℃ had the maximum protective effect.(2)Effect of tween 80 on the structural morphology of Bacterial subtilis sporesThe effect of HPTS combined with tween 80 on the spore structure and morphology was observed by using a granularity analyzer and SEM images.The results showed that 200 MPa,75℃,0.5%tween 80 treatment increased the particle size,which may be that tween 80 as an emulsifier,had a enhancing effect on spores and increased the spore particle size.The SEM images showed that after the addition of tween 80,the concentration of tween 80 effectively protected the integrity of the cell membrane surface without breakage.(3)Effect of tween 80 on the inner membrane permeability,membrane lipids,protein and nucleic acid substances of of Bacillus subtilis sporesThe effect of inner membrane permeability,membrane lipids,protein and nucleic acid substances of of Bacillus subtilis spores were studied.The results showed that tween 80 concentration could decrease the offset value of spore positive region M2 and reduce the change of permeability on spore membrane.200 MPa,75℃ combined with tween 80 treatment produced a good protective effect on the protein secondary structure,effectively maintained the stability of the protein secondary structure.(4)Effect of tween 80 on the morphology and key substances of Bacillus subtilis sporesAfter HPTS combined with tween 80 treatment,the changes of protein and nucleic acid release(OD280 and OD260),Na+/K+-ATP enzyme,Ca2+/Mg2+-ATP enzyme and SDH enzyme activity were also determined.The results show that HPTS alone treatment increased the release of protein and nucleic acids on spores,while after adding 0.5%tween 80 could reduce it.And the concentration of tween 80 had a strong protective effect on the Na+/K+-ATP enzyme,Ca2+/Mg2+-ATP enzyme and SDH enzyme activity,which can activate the spores enzyme activity.(5)Study on the bactericidal kinetics of HPTS combined with tween 80By analyzing the linear model and the Weibull model,the effect of tween 80 on spores.The results showed that the Weibull model had higher standardized regression coefficient(R2)and the residual square was relatively lower(the RSS)than the linear model was analyzed,so the fitting accuracy of the Weibull model was higher than that of the linear model.(6)Tween 80 weakened the sterilization effect of cantaloupe juice and the influence of fruit juice composition0.5%tween 80 weakened the sterilization effect of HPTS on cantaloule juice.Under 200 MPa,75℃、the 0.5%tween 80 favors the dissolution of total phenolic substances in cantaloupe juice. |
