Overview
Erythrosine, also known as Red No. 3, is an organoiodine compound, specifically a derivative of fluorone. It is a pink dye which is primarily used for food coloring. It is the disodium salt of 2,4,5,7-tetraiodofluorescein. Its maximum absorbance is at 530 nm in an aqueous solution, and it is subject to photodegradation.
Uses
It is used as a:
food coloring
printing ink
biological stain
dental plaque disclosing agent
radiopaque medium
sensitizer for orthochromatic photographic films
Visible light photoredox catalyst
Erythrosine is commonly used in sweets such as some candies and popsicles, and even more widely used in cake-decorating gels. It is also used to color pistachio shells. As a food additive, it has the E number E127.
From Wikipedia (CC BY-SA 4.0).