The Screening Of Fruit Fresh-keeping Function Bacterium And Its Application In Dimocarpus Longanan Lour

The paper dealt with the isolation of fruit fresh-keeping function bacterium and its application in Dimocarpus longanan Lour. The isolation of endophytic bacteria and pathogen that caused the postharvest disease in the fruit longan was conducted. The relationship between the rotting of longan fruit and the activity of enzyme was studied. The fruit fresh-keeping function bacterium was isolated to inhibit the enzyme of fruit longan in preventing the fruit from rotting. The results showed as follows.1,Pathogens were isolated and identified of longan fruits by the dilution plate method and Microbial Identification System (MIS). The results showed that: 54 strainns of bacteria and 15 strains of pathogenic fungi were isolated from different levels of longan fruit rot and they were Trichothecium roseum,Botryosphaeria parva,Staphyloccus simucans,Micrococcus lutens-GC,Brevibacillus choshinensis,Clavibacter micrhiganenisis. The contents of bacteria in peel were more than that in the pulp . We got an antagonistic bacterium strain(JK-2, Breivbacillus brevwas) which could keep the longan fruits fresh from various fruits and in our laboratory database.2,There was a closely relationship between the browning and decay of longan pericarp and the activity of POD(Peroxidase) and PPO(Polyphenoloxidase). Under the natural state, the activity of POD and PPO increasing gradually along with the decay of longan fruits. but SOD(Superoxide Dismutase)activity was contrary. The effects were different with the different concentrations of fermented of JK-2, the results showed that : the activity of POD,PPO and the MDA(malondiadehyde) content decreased after treated with 6×105 cfu/mL of fermented of JK-2 and the activity of SOD increased.3,The affection on the fresh of longan fruits by different storage methods was different. The results showed that the longan could be kept fresher with the enclosig of paper than leaves and the preservation was prolonged. The fresh level was different with the different using methods of strain JK-2. The results showed that the good fruit rate was higher than the control. It would be better if the strain JK-2 was used preharvest of longgan fruits than that used post harvest.