Stability of Betalain Pigment from Red Dragon Fruit (Hylocereus polyrhizus)
Betalain pigment from red dragon fruit (Hylocereus polyrhizus) or known as purple pitaya was extracted and the stability was evaluated. Fruits were homogenized with ethanol to separate pectic substances. The fruit extract obtained demonstrated absorbance peaks at 230 and 537 nm under UV/Vis spectrophotometric analysis. Absorbance peak at 537 indicated the presence of betacyanin. The changes of betacyanin intensity due to storage condition, light, temperature, pH and additives were monitored for three weeks with a UV/Vis spectrophotometer at 537 nm. Results revealed light as the major factor of betalain pigment degradation. Refrigeration storage (4°C) condition without light exposure managed to preserve the colour of fruit juice up to 3 weeks.