Basic Information :

Indigo Bule Solubility: slightly soluble in water, ethanol, glycerin and propylene glycol, insoluble in oils and fats. The 0.05% aqueous solution was dark blue. 1g is soluble in about 100ml, water at 25 ° C, the solubility in water is lower than other edible synthetic pigments, and the 0.05% aqueous solution is blue. Soluble in glycerin, propylene glycol, slightly soluble in ethanol, insoluble in oil. In case of concentrated sulfuric acid, it is dark blue, and after dilution, it is blue. Its aqueous solution plus sodium hydroxide is green to yellowish green. Indigo is easy to color, has a unique color tone, and is widely used. Heat resistance, light resistance, alkali resistance, oxidation resistance, salt tolerance and bacterial resistance are both poor. Fading when reducing, such as reduction with sodium sulfoxylate or glucose, it becomes white. The maximum absorption wavelength is 610 nm ± 2 nm.
Stability: light resistance, poor heat resistance, unstable to citric acid, tartaric acid and alkali.