CONSOLIDATION OF DEEP EUTECTIC SOLVENTS WITH MICROWAVE FOR THE EXTRACTION OF FERULIC ACID FROM THE FRUITLETS OF OIL PALM

This article reports the extraction of ferulic acid from oil palm fruitlets by using deep eutectic solvent (DES) with microwave assistance. The difference in the amount of ferulic acid extracted from unsterilised and sterilised oil palm fruitlets using DES with microwave assistance was not significant, signifying that sterilisation during palm oil milling did not have much effect on the content of ferulic acid in the palm fruitlets. Acetic acid (AA) is a better hydrogen bond donor than citric acid in choline chloride (ChCl) DES whereby higher amount of ferulic acid could be extracted from oil palm fruitlets when ChCl-AA was used as the extraction medium ( ca. 40.3 mg/g versus ca. 34.4 mg/g). The optimum conditions for the extraction of ferulic acid from palm fruitlets were by using ChCl with AA containing 30 wt.% water, heated with microwave at 60 o C for 6 min. Ferulic acid extracted from unsterilised oil palm fruitlets exhibited higher radical scavenging activity (92%-95%) than sterilised fruitlets extract (88%-92%), indicating that although the sterilisation process did not significantly affect the content of ferulic acid in the oil palm fruitlets, the bioactivity of the ferulic acid was slightly affected.