Optimization of conditions for organochlorine pesticide residues removal in apples using ultrasonic

China is the largest country in apple-producing in the world, but its apple export just accounts for less than 10% of world trade market. One of the main constraints is the pesticide residues in apples. The ultrasonic removal of organochlorine pesticide residues in apples was studied, and the response surface method was applied to analyze the influence of ultrasonic power, degradation time and degradation temperature on the removal rate. The influence of main quality indexes in apples caused by ultrasonic wave was also studied. The results indicated that: (1) The optimum removal conditions of organochlorine pesticide residues in apples were as follows: the ultrasonic power 609.16 W, the removal time 70.46 min, the removal temperature 15.45℃, and under this condition, the removal rate of organochlorine pesticide residues in theory could reached to 64.32%; (2) The rigidity of apples was not significant between the 17 groups of sonication samples and CK; whereas, the total sugar, total acid had a significant impact, but did not exceed national standards and apple quality standards of major exporter. Ultrasonic is an easy and quick handling technology, and can remove organochlorine pesticide residues effectively, enhance the safety of apple greatly. It is easy and available to couple with the cleaning, grading and waxing of fresh apple at present, and its industrialization has very broad prospects.