Fresh-Keeping Effects Of Dong Jujube And Residual Dynamics Using Natamycin Treatments In Low Temperature

Using Dong Jujube and Alternaria Nees ex Wallr, the toxicity of commonly used fresh-keeping fungicide and natamycin to Alternaria. Nees in different temperatures have been studied. The effect of different, film former and mixture of those to firmness, quality, physiological and biochemistry activity have been discussed. Screen out suitable concentration of natamycin, founded HPLC analysis methord of residual natamycin, and studied residual trend in low tempreture store time.The study showed that natamycin have good control effect to in normal temperature(25℃). EC50 values is 42.3371mg/L and EC90 values is 219.9808mg/L. The EC50 of prochloraz values is 9.8090mg/L and EC90 is 197.4251 mg/L. It's not remarkable difference form the 95%CL. The toxicity of different temperature showed that Natamycin had better effect in low temperature. The EC50 values is 1.1486mg/L in 5℃, it is 37 times than in 25℃. The negative temperature effect is evident.The study showed disposal with natamycin 500-1000mg/L before storage can repress increase of MDA and PG activity, enhance activity of PAL. It had good effect on keep firmness, and repressed decrease of soluble solid and Vc. It also can control infectious diseases such as Alternaria Nees ex Wallr and other rotten diseases. After treated with 500 mg/L and1000mg/L natamycin, commodity ratio were 85.1% and 87.3% respectively stored 60 days, after stored 100 days, commodity ratio were 72.2% and 75.0% respectively. Commodity ratio of prochloraz 500mg/L was 75.2% and CK is 50.2%.And the quality was very good. The treatment of natamycin plus PVA can enhance effect of natamycin.Residual experiment showed that natamycin was sprayed in 1000mg/L and 500mg/L after store period, the original aggradation were 0.789 and 1.012mg/kg. After spraying 10 days, residual natamycin were 0.371 and 0.411 mg/kg, decompose ratio were 52.98% and 60.67%. After 60 days, residual natamycin were 0.344 and 0.349 mg/kg, decompose ratio were 56.40% and 65.51%. All of above are under international criterion. According to this, we consider natamycin is secure in recommend dosage.