Natural Food Colours
Which flavonoid pigment is most unstable at alkaline pH?
Which flavonoid pigment is most unstable at alkaline pH?
Try to answer before revealing the correct option and explanation.
Correct Answer
✅ C. Anthocyanin
Explanation
Anthocyanins are highly sensitive to pH changes. At alkaline pH, their chemical structure changes, resulting in color fading or conversion to blue/green pigments.
Anthocyanin color changes:
- Acidic → Red
- Neutral → Purple
- Alkaline → Blue/green
Why Other Options Are Incorrect:
- Quercetin: Flavonol and comparatively more stable.
- Catechin: Flavanol, mainly associated with taste.
- Hesperidin: Citrus flavanone
Key Concept
Anthocyanins = pH-sensitive Natural color indicators Water-soluble pigments
Related Sub-categories
References
- Damodaran, S., Parkin, K. L. (2017). Fennema’s Food Chemistry (5th Edition). CRC Press.
- Belitz, H. D., Grosch, W., & Schieberle, P. (2009). Food Chemistry (4th Edition). Springer.
- deMan, J. M. et al. (2018). Principles of Food Chemistry (4th Edition). Springer.
- Shahidi, F., & Naczk, M. (2004). Phenolics in Food and Nutraceuticals. CRC Press.
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