Is Acid Orange 5 vegetarian?
Acid Orange 5
Tropaeolin OO (Acid Orange 5) is a synthetic azo dye with the formula Na(C6H5NHC6H4N=NC6H4SO3). It is used as a pH indicator, appearing red below pH 1.4 and orange-yellow above pH 3.2. It is produced entirely from synthetic precursors.
| Also known as | Acid Orange 5, Fast Yellow |
|---|---|
| CAS number | 554-73-4 |
| CI number | CI 13080 |
| Last reviewed | 3 June 2026 |
An ingredient is considered vegetarian if it avoids components derived from killing an animal.
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