Total phenolic content and antioxidant activity assessed using coff ee grounds at Daklak

Abstract

Extraction of antioxidant phenolic compounds from used coffee grounds (SCG) has been studied. Extraction experiments were performed by conventional solid-liquid method, using ethanol as solvents at different concentrations (0 - 90%, v/v), material/solvent ratio (1:10 – 1:40 g/ml), extraction time (10–80 minutes), and temperature (30 - 70^oC), pH (2 - 8). The efficiency of the extraction was assessed through the determination of the total phenolic content. The antioxidant activity was also assessed through its H₂O₂ inhibitory ability. In general, the extraction efficiency is best when using a 50% ethanol solvent; A suitable ratio of material/solvent (NL/DM) is 1:40 (g/ml); temperature 60^oC, extraction time is 45 minutes, pH = 5. Phenolic content is 20,825 mg of gallic acid/g of raw material. Good antioxidant activity with IC₅₀ is 313,447 µg/ml. These findings are of interest because antioxidant phenolic compounds have a prominent role in the medical field and their wide applications in food and pharmaceuticals.