values of MFR extracts at wave length of 485 nm at one hour and 96 hours. The results obtained are illustrated in Figure 1. Data showed that the absorbance of MFR pigments was decreased under acidic conditions. However, the absorbance of this pigment was almost stable at pH value 5- 6. After 96 hours, the stability of MFR pigments was decreased significantly and showed the similar trend with one hour samples. Fabre et al.7 reported that pigment from angkak is more sensitive to acidic pH and more stable in alkaline or neutral pH. In acidic pH, more electrons (H+) content in angkak pigments lead to chromophore degradation compared to alkaline pH. By decreasing the pH, colour intensity of angkak pigments was also decreased. This property was different with anthocyanin pigment content in rosella flower. By increasing pH value of the extract up to 4-5, the red colour greatly faded and almost appeared colourless at pH value of 6.05. The structure of anthocyanin at pH value of 1.0 showed as the oxonium form which has red colour and at pH value of 4.5 showed as the carbinolor hemicetal form8.