Color Properties and Stabilizing Effect of Metal Ion on Anthocyanin from Buni (Antidesma bunius) Fruit

The objectives of this research were to evaluate the possibility of metal complexation in generating blue color, and the stability of the anthocyanin from Buni (Antidesma bunius) fruit extract. Four different metals ions (Ca 2+ , Mg 3+ , Al 3+ , and Fe 3+ ) have tested at three concentrations level (0 ml, 0.01 ml, and 0.02 ml of 0.1 N solution per ml extract). The divalent Ca 2+ and Mg 2+ ions made an impact minimally to the bathochromic and hyperchromic shift at pH 3-8. The trivalent Fe 3+ successfully generated a bluer color at all pH, while the Al 3+ did not work only at pH 3. Stability test at pH 6-8 showed that the best stability occurred at pH 6. However, the metal complexation samples performed lower stability than the control samples.