Optimization of extraction process and evaluation of antioxidant activity in vitro of anthocyanins from coffee pericarp by ultrasonic-assisted enzyme method

Abstract

In order to explore the extraction process and antioxidant activity in vitro of anthocyanins from coffee pericarp, the anthocyanins from coffee pericarp was extracted by ultrasound-assisted enzymatic method. The extraction process of anthocyanins from coffee pericarp was optimized by single factor tests and orthogonal tests, and the antioxidant activity in vitro was studied. The results showed that the optimal extraction conditions for anthocyanins from coffee pericarp were as follows: extraction temperature 60 ℃, ethanol volume fraction 60%, pectinase addition 2%, solid and liquid ratio 1∶50 (g∶ml), extraction time 40 min. Under the optimal condition, the anthocyanin yield of coffee pericarp reached 0.274%. The results of antioxidant activity in vitro tests showed that when mass concentration of the sample was 30 μg/ml, the scavenging rates of DPPH and OH radicals were 91.40% and 67.28%, respectively, and the semi-inhibitory concentration (IC50) values were 6.36 μg/ml and 12.16 μg/ml, respectively. When mass concentration of the sample was 5 μg/ml, the total reduction capacity was the highest (absorbance value was 0.987). Therefore, coffee pericarp anthocyanin had certain antioxidant capacity.

Keywords

• coffee pericarp|anthocyanin|ultrasonic-assisted enzymatic method|extraction process|antioxidant activity in vitro