Optimization of Natural Colour Extraction from Dragon Fruit (Hylocereus polyrhizus) Peel

Abstract

Dragon fruit (Hylocereus polyrhizus) which comes from family of Cactaceae is one of the tropical fruit in Malaysia. The peels of red dragon fruit are the possible sources of betacyanin, which responsible for the red-violet color even though the peel always regarded as a waste. The objective of this study is to assess the stability of natural pigment extract from dragon fruits peels by using simple water extraction method and assessed by ultraviolet-visible (UV-Vis) spectrometer. The extracted natural pigments then were introduced to several optimization conditions such as extraction time (1 – 6 hours), temperature (25 – 100 °C) and a range of pH (2 – 12). This study was also investigated the stability of natural pigment towards light. Results analysis of dragon fruit peels extracted shown that the optimum conditions were 4 hours of extraction time, 25 °C and pH 5. Sample extraction of natural pigment that has been optimized was more stable compare to control when exposed to light. In addition, the natural pigment extracted from dragon fruit peel was characterized by Fourier transform infrared (FTIR) spectrometer. In conclusion, the natural pigment extracted by using solvent extraction method from dragon fruit peels has ability to be used as natural colorant.