Extraction of antioxidant compounds from the wastes of Mangifera pajang fruit: a comparative study using aqueous ethanol and deep eutectic solvent

The extraction of antioxidant compounds from fruits wastes of Mangifera pajang using conventional solvent (ethanol) and deep eutectic solvent (DES) was investigated. A statistical optimization study was first performed to maximize the antioxidant activity from ethanol extraction, which led to a maximum antioxidant activity of 11.11 +/- 0.06 mg AEAC/g. The optimized parameters were then used in the DES extraction study. Among the several formulations of DESs, the solution where choline chloride mixed with glycerol (CHCL-GLY) resulted in the highest antioxidant activity. Subsequently, the CHCL-GLY formulation was further optimized by adjusting the molar ratio of the glycerol and the water concentration in the solution. The results showed that the CHCL-GLY solution with a molar ratio of 1:2 and addition of 20% water gave the highest antioxidant activity at 11.48 +/- 0.09 mg AEAC/g, slightly outperformed the extract obtained by aqueous ethanol, indicating that DESs can be an excellent solvent for extracting antioxidant compounds from plant material which lead to novel industrial applications.