Extraction of Phenolic Compounds from Waste Coconut Coir Dust Using Ultrasound-Assisted Solvent Extraction

In the present study, phenolic compounds were extracted from waste coconut coir dust, a by-product of coconut manufacturing process, for value-added. The objective of this research was to determine the optimal extraction condition of total phenolic contents from coconut coir dust using ultrasound-assisted solvent extraction. In the extraction, three main parameters: solvent types, extraction temperature and extraction time were used to determine the optimal extraction condition of phenolic compounds from the sample. It was found that the extraction of sample with 50% (v/v) ethanol at 30 ºC for 120 minutes gave the highest crude extract yield (29.57% w/w on dry basis) and the highest total phenolic content (951.33 µg GAE/g). The antioxidant activities of crude extract from the optimal extraction condition was further investigated by comparing the two most common radical scavenging assays namely, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). The results showed that the crude extract exhibited strong antioxidant activities with IC50 at 362.77µg/ml by DPPH, and 11.96 µg/ml by ABTS methods, respectively.