Optimization of Ultrasonic Assist Extraction Conditions of Apple Polyphenol

The influence of ethanol concentration,extraction time,pH,solid /liquid rate,particle size and ultrasonic power on the extraction efficiency of apple polyphenol under the condition of ultrasonic assisted extraction are studied through multi-factor orthogonal experiment. The extraction efficiency of apple polyphenol increased with the increase of extraction time,solid/liquid rate and ultrasonic power, decreased with the increase of pH, with a peak at pH 3. When the ethanol concentration increased from 0 to 100%,the extraction efficiency of apple polyphenol increases initially and decreases afterwards and reaches the highest value when the concentration of ethanol is 75%. The influence of particle size on extraction efficiency of apple polyphenol is in contrast with that of ethanol concentration,and when the particle size is 60 mesh,the extraction efficiency reached maximum level. These results show that the optimum extraction conditions of ultrasonic assisted extraction of apple polyphenol are 50% of ethanol,60 minutes of extraction time,pH 3,1∶6 of the solid-liquid ratio,60 mesh of particle size and 80 W of ultrasonic power,considering the yield of apple polyphenol and the economy. The yield of apple polyphenol can be up to 1 692.72 mg/kg under the optimized conditions.