The term natural colorant comprises all kind of materials available from natural sources which are able to impart color to matter.
The main principle of color development for natural colorants is the specific absorption of light in the wavelength region of 400–700 nm .
Other principles on color formation may be based upon physical effects, for example, refraction of light (rainbows), interference (feathers of peacocks), or electron excitation (electroluminescence) .
Sources for natural colorants include minerals (red ochre, α-Fe2O3), plant material (e.g., flavonoids from Canadian golden rod), and animal-based dyes (e.g., indigoid colorants from selected mollusc species).
Colored pigments are applied as finely divided solid particles which remain in an insoluble state during their application and use. Water-soluble or oil-soluble natural colorants can be found in food and beverage applications. A colorant that is...
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