Extraction of Anthraquinone Compounds from Chinese Chestnut by Using Ultrasonic-assisted Technology

Abstract

Ultrasonic assisted method was used to extract total anthraquinone compounds from non-enzymatic Browning chestnut kernel. The chestnut was heated in the microwave on 640w by a stainless steel knife for 60 s. Then fried it by heating 120°C for 30 min method result in non-enzymatic until browning of chestnuts fully. The anthraquinone in Chinese chestnut was extracted by ultrasonic cleaner with frequency of 80 kHz and power percentage of 80%. The absorption value was measured and calculated at 254 nm by ultraviolet spectrophotometer. The effects of ethanol concentration, ultrasonic time, extraction temperature and liquid-solid ratio on extraction efficiency were studied. The effect level of different factors on the extraction efficiency of anthraquinone compounds was as follows: liquid-solid ratio>Ultrasonic time > ethanol concentration > extraction temperature. The extraction rate of anthraquinone increased and reached the hightest point when liquid-solid ratio was between 2/1 and 4/1, and it decreased as the liquid-solid ratio rise. The extraction rate of anthraquinone increased with the increase of ultrasonic time, which was the maximum when ultrasonic time was 30 minutes, and the extraction rate remained stable. The extraction rate of anthraquinone increased with the increase of ethanol concentration. The extraction rate reached the maximum when the ethanol concentration was 80%, and tends to be stable with the increased of the concentration. The extraction rate of anthraquinone was increased sharply before the temperature reached 60°C. And it maintained stable at the highest point between 60°C and 70°C. According to the regression equation and the single factor experiment, the optimum extraction technology were ethanol concentration (85%) ultrasonic time (35min) extraction temperature (60°C) and liquid-solid ratio was 4.5:1. The extraction rate of chestnut anthraquinones was up to 77.31μg/g dry weight.