Study On The Degradation Of Organophosphorus Pesticides Residue In Apple Juice

China is not only the biggest apple production country but also the biggest exporting country of concentrated apple juice. However, in recent years, the organophosphorus pesticides residue has been one of the main bottlenecks affecting concentrated apple juice exporting. In order to seek an efficient method for degradation of organophosphorus pesticides with the the quality of apple juice maitained as well as possible, nine organophosphorus pesticides such as methamidophos, acephate, phorate, dimethoate, chlorpyrifos, methyl- parathion, malathion, fenitrothion, parathion and so on in apple juice which must be detectected were treated by ⁶⁰Co-γray radiation, ultra-high pressure, ultrasonic and combined methods. The main results showed:1. ⁶⁰Co-γray radiation has the most remarkable effect on the degradation of organophosphorus pesticides such as fenitrothion, parathion, methyl-parathion, phorate and chlorpyrifos and the maximum degradation rates are all over 85%. The degradation rates of methamidophos, acephate, malathion, dimethoate are slightly inferior to the above five pesticides and the optimum degradation rates is just 34.70%. Meanwhile, at the range of 0～9 kGy , the contents of soluble total sugars, glucose, fructose, sucrose and total sugars in apple juice decrease unconspicuously, but the total acid content in apple juice and its color value and clarity increase. However, the changes of main chemical and physical indexes are not significant.2. Through the methods of single factor and orthogonal design, the optimal degradation condition by ultrasonic is ultrasonic power 360W, ultrasonic time 60min, ultrasonic temperature 45℃. Meanwhile, the main chemical and physical indexes of apple juice could be affected to some extent while organophosphorus pesticides were degraded by ultrasonic, but the changes are not significant.3. Ultra-high pressure has the most remarkable effect on the degradation of the six organophosphorus pesticides except methamidophos, acephate, dimethoate. The maximum degradation rates of methamidophos, acephate, dimethoate is just only 30%, the maximum degradation rate of malathion is about 80%, the maximum degradation rates of others are over 90%. At the same time, ultra-high pressure treatment on apple juice has little influence on quality index of apple juice and a good retention of nutritional ingredients such as soluble solid content, total acid, reducing sugar and so on. The relative percentage content of the main chemical and physical indexes of apple juice is over 95%.4. The combined technology of ultrasonic with ultra-high pressure have been attempted to degrade the organophosphorus pesticides in apple juice, Ultra-high pressure has more remarkable effect on the degradation of the organophosphorus pesticides in apple juice, the degradation effect of ultra-high pressure was signifcantly better than that of ultrasonic. There were no significant differences of degradation between the single ultra-high pressure and the combined technology. But, the combined technology was beneficial to improve the degradation effect of ultrasonic. Calculation of using ultra-high pressure selectively by the premise of ultrasonic degradation to increase the degradation effect furthest.