OPTIMIZATION OF UTRASONIC ASSISTED ETHANOL EXTRACTION OF BLUEBERRY ANTHOCYANINS BY RESPONSE SURFACE METHODOLOGY

The aim of this study was to fully utilize the blueberry skin residues after juicing and maximize the value of blueberries.The anthocyanin in blueberry skin residues were extracted once by the ultrasonic-assisted ethanol extraction.The effect of liquid-to-material ratio,ultrasonic time,ultrasonic temperature and ultrasonic power on the extraction rate of anthocyanin were investigated and the optimal extraction conditions were obtained by the response surface methodology.The results demonstrated that the extraction rate of anthocyanin in the blueberry skin residues using the ultrasonic-assisted ethanol extraction was significantly higher than that just using the ethanol.The optimal extraction conditions were:ultrasonic extraction time of 20 min,extraction temperature of 40℃,extraction power of 60 W and liquid-to-material ratio of 4:1 mL/g.Under these conditions,the extraction rate of blueberry anthocyanin reached to (205.13±0.45) mg/100 g,the extraction time of anthocyanin in blueberry skin residues was shortened greatly.In addition,this method was simple and effective,and could be used in the batch extraction.