Optimization of Extraction Solvents on the Antioxidant Properties of Coconut Waste

Cocos nucifera L. (family Arecaceae) commonly known as coconut is considered as an important fruit crop in tropical countries and are widely used for therapeutic and domestic purpose. They have effective properties such as antioxidant, antitumor, antiseptic and antimicrobial. The growing demand for green coconut water consumption and food industries cause the dumping of the shell and husk of this fruit, generating large amount of solid waste. This study utilized part of coconut waste to study the impacts of solvent type on the phenolic content. Six different polarities of solvent were chosen. Total phenolic content was performed using Folin-Ciocalteu assay and free radical scavenging activity with 2,2-diphenyl-1-picrilhydrazil (DPPH) method. Total phenolic content for coconut shell was the highest at 71.57 ± 0.275 mg GAE/g for propanol extract and 74.10 ± 0.741 mg GAE/g for acetone extract of coconut husk. The antioxidant activity of all sample extracts was analysed using DPPH assay. Highest radical scavenging activity of coconut husk was observed by propanol extract with 93.82 ± 0.052 % while the lowest scavenging activity was demonstrated by chloroform extract with percentage of 57.77 ± 2.255%. Acetone extract of the shell exhibited the highest scavenging activity of 91.23 ± 0.073%, while chloroform extract of coconut shell demonstrated the lowest antioxidant activity of 70.627 ± 0.467%.