Study On Bamboo Vinegar For Apple Preservation

Chemical fungicides play an important role in antisepsis and freshness of fruits and vegetables, but there are many issues such as pesticide residues, environmental pollution, health hazards and so on. China owns the most abundant bamboo resources in the world, but the chemical utilization of bamboo vinegar is not sufficient. In order to control fruits and vegetables storage diseases, decrease chemical fungicides application and widen the chemical utilization of bamboo vinegar, it is essential that bioactivity of bamboo vinegar against several species of plant pathogenic fungi. Therefore, the aim of this study is to determine antimicrobial property of bamboo vinegar for future application as preservative agent with high efficiency and low toxicity.The main results were as following:1. The antimicrobial activity of four bamboo vinegars and six chemical fungicides against Colletrichum gloeosporioides, Valsa mali and Botrytis cinerea were evaluated. Prochloraz, tebuconazole and one bamboo vinegar exhibited significant antifungal activity.Synergism between prochloraz, tebuconazole and the selected bamboo vinegar were also studied in a bioassay. Synergistic action of No1 bamboo vinegar on two chemical fungicides has been found. The CTCs of the combinations were 261.23 and 249.49 for tebuconazole/bamboo vinegar and prochloraz/bamboo vinegar respectively, at the ratio of 1:5 based on EC50.2. The antimicrobial activity of synergistic combination, bamboo vinegar and combination against Valsa mali in vivo experiment were evaluated. 5 days after inoculation, synergistic combination showed promoting effect on Valsa mali, the control efficiency was -5.38%. Bamboo vinegar had a little inhibitory activity on Valsa mali, the control efficiencies were ranged from -3.71 to 7.02%, the concentration of bamboo vinegar has little influence on antimicrobial activity in vivo experiment. Acetic acid and neutral pH bamboo vinegar had promoting effect on Valsa mali, the control efficiencies were -0.91% and -41.55%, the acidic components of bamboo vinegar have little influence on antimicrobial activity in vivo experiment. The control efficiency of prochloraz/bamboo vinegar, which concentration of prochloraz was 125mg/L, was 90.06%; the control efficiency of prochloraz, which concentration of prochloraz was 250mg/L, was 84.79%; there was no significant difference between them.3. Orthogonal experiment showed that the packaging method of samples had significant effect on the control efficiency of 1% prochloraz/bamboo vinegar emulsion in water(EW) against apple canker after treatment. The optimized application technology was as following: 1%prochloraz/bamboo vinegar EW was diluted 100 times, sprayed the samples before inoculation, used non-seal package after treatment. 5 days after treatment, experiment of the optimized application technology demonstrated that the control efficiency of 1% prochloraz/bamboo vinegar EW against apple canker was a little greater than 250mg/L single dose of prochloraz, the control efficiencies were 73.91% and 72.82%, there was no significant difference between them.4. An analytical method of prochloraz residues in appales was developed, and the prochloraz residues in appales treated by combination were detected. Apple samples were extracted by acetonitrile and detected by liquid chromatography with UV detector. The method had good linearity in the circumscription in 0.625ng-50ng, the detectable limit was 0.016mg/kg. The average recoveries of prochloraz in appales were ranged from 83.27% to 89.62%, the relative standard deviations (RSD) were ranged from 10.65% to 11.60%. This method can meet the requirement of pesticide residue analysis.The prochloraz residues in appale samples were detected. 5 days after treatment, the residue of prochloraz in apples treated by single dose of prochloraz was 1.50mg/kg, the residue of prochloraz in apples treated by 1% prochloraz/bamboo vinegar EW diluted 100 times was 0.78mg/kg.