The Killing Method Of Osmotolerant Yeast From Apple Juice By Pulsed Discharge Plasma

China is the world's largest producer of concentrated apple juice,Chinese concentrated apple juice exports accounted for more than half of the world trade volume.At present,Chinese concentrated apple juice exported to Europe often lead to trade disputes and quality issues due to osmotolerant yeasts contamination.Looking for a safe and efficient method to kill the osmotolerant yeasts in concentrated apple juice become the urgently solved key technical problems for industry.A self-assembled Pulsed Discharge Plasma device was developed and used to study the bactericidal effects of electrical parameters(voltage,ventilation,exposure time),solution parameters(Juice soluble solid concentration),the initial concentration of the Zygosaccharomyces rouxii LB,and the difference of bactericidal effects of different strains was compared.Moreover,the effects of Pulsed Discharge Plasma on apple juice quality were studied by measuring the main physical and chemical indexes,organic acid content,polyphenols content and volatile flavour compound.The main research results are as follows:(1)Separation of bacteria LB and standard bacteria JCM5924 had better tolerability and were able to grow rapidly in the apple juice,They can make apple juice color value,light transmittance,soluble solids,p H value,reducing sugar content reduce and apple juice turbidity,titratable acid content increase.When inoculation apple juice was training for 84 h,apple juice clarification would be cloudy and alcohol and carbon dioxide gas were produced.The apple juice went bad.(2)The germicidal efficacy was influenced by pulse voltage,ventilation,exposure time and juice soluble solid concentration.The results showed that when juice soluble solid concentration,juice p H,pulse voltage,ventilation and initial cell density were 12 %,3.84,24 k V,150 m L/min and 1.08 × 104 CFU/m L respectively,the Zygosaccharomyces rouxii LB could be effectively inactivated in five minutes by Pulsed Discharge Plasma.(3)The pulsed discharge plasma had no significant effect on the basic physical and chemical indexes,organic acids,polyphenols and volatile flavor substances of apple juice(P<0.05),and could maintain apple juice quality.This study may provide an important method basis for the application of Pulsed Discharge Plasma in food sterilization of microorganisms.