Comparisons between Conventional and Microwave-Assisted Extraction of Natural Colorant from Mesocarp and Exocarp of Cocus Nucifera

This study aimed at exploring the feasibility of using the mesocarp and exocarp ofCocus nucifera as a natural colorant using microwave-assisted extraction in which often regarded as a waste materials. The effects of microwave power and heating time on the yield of colorant, pH and colour determination were investigated. The highest colorant yield in mesocarp and exocarp was found to be 6.0% （8 min of extraction at 100 W） and 6.8% （12 min of extraction at 300W）, respectively. While the control, extraction of colorant by conventional method （90 min at 90 ℃）, showed a percentage of 5.2% （mesocarp） and 3.6% （exocarp） yield of colorant. Meanwhile, pH of all extracts fluctuated throughout the experiment. The results proved that heating time and microwave power slightly affected the pH of all samples due to pH being inconsistent throughout the experiment. In colour determination, lightness （L^＊） was slightly decreased for all samples which extracted at all microwave power which indicated that the longer the heating time the darker colour was extracted. Overall, the colour of exocarp was darker than mesocarp extract due to L^＊, c^＊ and h^＊ values were lower than the mexocarp extract. The utilization of microwave-assisted extraction has significant improvement in the extraction of natural colorant compared to traditional boiling method. In fact, application of microwave irradiation method proved to be a rapid and improved technique for natural colorant extraction and extensively reduced the extraction time.