Extraction of flavonoids from avocado peel and purification with macroporous resin

The optimization of extraction technology with traditional orthogonal design and further purification with macroporous resin of flavonoids from avocado peel were studied. The results show that the optimum extraction conditions are as follows: ethanol concentration is 70%, extraction temperature is 70℃, extraction time is 1.5 h and the ratio of avocado peel to ethanol (m/V) is 1︰20. The factors of ethanol concentration and extraction temperature have significant effects on the yield of avocado peel flavonoids. Under the optimal conditions, the yield of avocado peel flavonoids is 1.12%. The AB-8 type macroporous resin has better effect on adsorption and elution of flavonoids from avocado peel. The purification conditions are as follows: the co column volume is 250 mL, the sample quantity is 2.03 g, the column is washed with water and eluted with about 500 mL of 75% ethanol. Under these conditions the AB-8 type resin can be used six times repeatedly. Relative purity of the purified is 82.37% and the corresponding recovery is 71.65%.