Abstract: A quadratic orthogonal rotation combination design was used to explore the effects of ethanol concentration, material-to-liquid ratio, extraction time and extraction temperature on extraction rate of anthocyanidin from black mulberry (Morus nigra L.) by ultrasonic-assisted extraction. A regression equation was established using DPS7.05 software. The optimal extraction conditions were found to be 52.46%－55.93% ethanol as extraction solvent at a liquid-to-material ratio of 39.51:1－42.43:1 (mL/g) for 27.77－32.23 min of extraction at 50.18－52.4 ℃. Under these conditions, the extraction rate of anthocyanidin was more than 67%.

Key words: black mulberry, anthocyanidin, orthogonal rotation combination design, extraction, optimization