The Difference in Colour Shifting of Clitoria ternatea L. Flower Extract at pH 1, 4, and 7 During Storage

Objective: A research to evaluate the colour shift of Clitoria ternatea L. flower (CT) extract at pH 1, 4, and 7 during storage at 30oC in the dark has been conducted. Methods: The evaluation comprised of the measurement of colour intensity (CI), violet index (VI), and browning index (BI). Results: The extract was very stable at pH 1, although its colour slightly shifted to redder. Conversely, at pH 4 the extract slightly decreased, but the colour hue remained stable. At pH 7, the extract exhibited much less colour stability by demonstrating considerable decrease of CI and VI. Conclusion: The absence and presence of the colour shift at pH 4 and 7, respectively, indicated that there were two different ways of the colour fading. It was proposed that the colour degradation at pH 4 occurred through the unfolding of hydrophobic interaction, while at pH 7 through the deacylation. The deacylation was proven by the high-performance liquid chromatography analysis equipped by diode array detector at 530 nm.