Optimization of Ultrasonic Extraction Technique of Proanthocyanidin from Peanut Skin

Orthogonal test method was applied to optimize the ultrasonic extraction of proanthocyanidin from peanut skin. On the basis of single factor test, the influencing factors of extraction power, temperature, time, solid-liquid ratio, ethanol concentrationultrasonic frequencies were determined by orthogonal test method with five factors and four levels in the ultrasonic frequency of 28 KHz. The results of the orthogonal test showed , the effects of five factors on ultrasonic extraction of proanthocyanidin from peanut skin were listed in the order of importance as: solid-liquid radio > ultrasonic power > time > temperature > ethanol, the optimum extraction conditions were as follows: ultrasonic output power 120W , extraction temperature 35°C, extraction time 5 min, solid-liquid ratio 1:24, ethanol concentration 55%.Under the optimum extraction, the extraction rate of proanthocyanidin was 12.1%.