Ultrasound-assisted extraction of natural dye from exocarp and mesocarp of Cocos nucifera

摘要

There is an abundance of waste contributed by most agricultural industries. Coconut industry wastes such as the (exocarp) outer layer and (mesocarp) husk can be exploited and turned into useful products such as natural dyes. In the present work, solvent extraction of natural dye from exocarp and mesocarp of Cocos nucifera using ultrasound has been studied. Methanol, ethanol and acetone with varying concentration (20%-70%) were used in the extraction process which was carried out at 30°C for 1 hour. Aqueous extraction was also performed with the same condition and acts as a control sample. The extraction of pigment from exocarp using 50% acetone produced the highest percentage of the yield of colorant (11.6%), while for mesocarp extraction, both 50% and 60% acetone yielded the highest percentage of colorant which was 9.2%. In addition, control sample (aqueous extraction of mesocarp and exocarp) showed lower percentages of the yield of colorant which was 6.4% and 6.8%, respectively. The results indicate that there was a significant improvement in the percentage of yield of natural colorant obtained due to the use of ultrasound.