Effect of the extraction conditions on the antioxidant capacity of phenolic compounds from pomegranate shell

Abstract

In the present study, two extraction methods were evaluated (maceration and ultrasound) to obtain the phenolic compounds content in pomegranate shell. The test parameters were temperature (30, 60 and 90°C), mass/volume ratio (m/v; 1:10, 1:25 and 1:50) and solvent (water, ethanol:water, 50:50 and ethanol). The antioxidant activities of the extracts were examined by three different methods, ABTS, DPPH and lipoperoxidation assays. The results showed that the best extraction conditions were: m/v ratio of 1:50 (0.02 g/mL), water as solvent and a temperature of 60°C, which prevent the degradation of the phenolic compounds and loss of the antioxidant activity (AA). Under these conditions, values of phenolic compounds, AA-DPPH and AA-ABTS were increased up to 10.41, 7.41 and 8.30-fold higher with respect to the control, respectively. Total phenols content, AA-DPPH and AA-ABTS by maceration were ≈1.36-fold higher than those obtained under ultrasound-assisted extraction.