Natural pH Indicators and their Sensitivities to pH


  • Nimrit Sidhu
  • Simrat Mahil
  • Shuwen Liu
  • Cindy Kim


Anthocyanins are a class of colorful compounds typically found in plant foods and are widely
used for their color in the food industry. They tend to appear red, purple, blue, or black. Given
anthocyanins’ ability to fluctuate in their color properties, this instability has also been applied for use as a
pH indicator in the food industry. This study analyzes the sensitivities of various anthocyanin-containing
foods as pH indicators, as assessed by their color changing property and deviance in color between
solutions with a pH difference of 0.5. Solutions of blackberries, black grapes, raspberries, blueberries, red
cabbage and plums were derived, and reacted with household low-pigmented test ingredients ranging
from a pH of 2 to 9. Pigmented aqueous solutions of red cabbage, blackberries, blueberries, plums, black
grapes and raspberries showed a significant color difference between all pairs of test ingredients with a
pH difference of 0.5.