Chlorophyll Color and pH Stability
Question
Could you please provide the color range of chlorophyll based on pH, similar to the information available for anthocyanins? Specifically, I would like to know what color it will be at pH 3.5-4 and if it can be used in formulations with this pH.
Answer
Chlorophyll's color is highly dependent on pH, but unlike anthocyanins which show a range of vibrant colors, chlorophyll degrades in acidic conditions.
At pH 3.5-4, which is acidic, chlorophyll is unstable. The magnesium ion in the molecule is replaced by hydrogen ions, forming pheophytin. This causes the color to change from vibrant green to brownish-olive or greyish-green.
Therefore, chlorophyll is generally not suitable for use in formulations with a pH of 3.5-4 if you want to maintain a green color, as it will quickly turn brown/grey. Chlorophyll is more stable and retains its green color in neutral to alkaline conditions (pH 7 and above).