Effects of Solvent Type and Concentration of Citric Acid on the Extraction of Antioxidants from Hom Nin Rice

Abstract

This research aimed to study the use of different solvents for the extraction of antioxidants from Hom nin rice. The solvents used were water, methanol and ethanol in combination with citric acid at concentrations of 0, 0.05 and 0.1mol/dm3. The effectiveness of the antioxidants was measured by the ABTS DPPH and FRAP assays. The contents of phenolic compounds and anthocyanins were also determined. The results showed that the extracts obtained using water with 0.1 mol/dm3 of citric acid exhibited the highest anthocyanin content (23.01 μg/ml). Water was noted to have similar extraction efficiency to methanol. However, using water as an extraction solvent led to the extract with higher anthocyanin content and antioxidant activity (via both the ABTS and FRAP assays) than by using methanol.