Application Of A Microbial Preservative In Fruit

This research paper mainly focuses on Bacillus amyloliquefaciens NCPSJ7and HQ222inApple and Sydney preservation. After postharvest, fruits are vulnerable to mildew such asPenicillium and Botrytis cinerea，However, some microorganism including Bacillusand yeasthas the antagonism effect to mildew. Because of many advantages such as wide distribution, lownutritional requirements, high antagonism efficient, security and environmentally friendly,bacillus become the best candidate in biological corrosion research. Bacillus amyloliquefaciensNCPSHQ222and NCPSJ7are the research objects, which are isolated from soil. Two bacterialcolonization experiments on fruit were measured by the Oxford cup method for thedetermination of two kinds of Bacillus processing liquid inhibition zone size with piricolaLW182and pears Penicillium bacteria ACCC37275as indicator bacteria. These processesinclude liquid bacterial suspensions, broth supernatant, antibacterial protein crude extracts andfruit preservative experiment to determine the effect of one or two relatively good preservationof Bacillus subtilis, and a good part of its preservation effect, and determine the optimal spraydrying conditions and the minimum inhibitory concentration, to develop a Fruit and Vegetablepreservation drugs. Test methods and results of this experiment are as follows:1. The first chapter, mainly introduced the background and significance of this research, aswell as the research progress in fresh-keeping field both in domestic and abroad and generalmethods of fruit fresh keeping. Meanwhile, it indicated the application of the starch bacillus andits antibacterial mechanism. Finally, the research basis, technical route and research content wereshown in this study.2. In the second chapter, we measured NCPSJ7and NCPSHQ222fruit colonization and itsinhibitory effect. The Oxford, fruit cup and fruit entity experiment were used to test the twoentities Bacillus amyloliquefaciens NCPSJ7, broth NCPSHQ222of their bacterial suspension,the supernatant, antibacterial protein crude extracts of the fruit as well as suppression of colonization bacterial effect. The results showed that both Bacillus amyloliquefaciens on applesand pears colonization had a significant inhibitory effect.3. In the third chapter, antagonistic bacteria and their antagonistic substances were identified.In order to determine the active ingredient of the two strains, the two bacterial NCPSJ7andNCPSHQ222were fermentateed6d bacterial suspensions, antibacterial protein crude extractswere taken two pathogen indicator bacteria were taken as indicator bacteria, fruit corrosionexperiments were used to test inhibitory effect to pathogens; and the treatment liquid wereelecting for pathogens. The results showed that all four treatments had inhibitory effects onpathogens, among them the antibacterial protein crude of Bacillus amyloliquefaciensNCPSHQ222extracted the most obvious effect.4. In chapter IV，we optimized the spray drying conditions of antimicrobial agents. Usingdifferent feeding temperature and inlet flow to spray drying the antibacterial protein crudeextracts of NCPSHQ222, two pathogen indicator bacteria were taken as indicator bacteria; theOxford cups were used, to determination of the size of the inhibition zone; Comparative stickywall were used to determine the optimal spray drying conditions. The results showed that theoptimal conditions NCPSHQ222antibacterial protein crude extracts of spray-dried was that theinlet temperature of130℃, and inlet flow rate of3.3mL/min.5. In the fifth chapter, the minimum inhibitory concentrations of the two pathogens wereidentified. To determine the minimum inhibitory concentration of Bacillus amyloliquefaciensNCPSHQ222to Piricola LW182and Pears Penicillium bacteria ACCC37275, antibacterialprotein crude extracts of NCPSHQ222were spray dried under the best conditions to ensure thatlosses to a minimum. The powder was dissolved in different concentrations, using PiricolaLW182and Pears Penicillium bacteria ACCC37275as indicator bacteria, using Oxford Cup toassay inhibition zone size and using its presence to determine the minimum inhibitoryconcentration of the antimicrobial protein crude extracts. We ultimately measured the minimuminhibitory concentration to Piricola LW182is1×10-3g/mL, the minimum inhibitoryconcentration to Pears Penicillium bacteria ACCC37275is1×10-4g/mL.In this paper, an antagonistic strain is screened, the antibacterial protein crude extracts of fruitsand vegetables are clear preservative effect. The experiment on preservation of fruits provides a scientific basis, laying the foundation for the industrial production of microbial preservative.