Abstract:

For development and utilization of natural pigment, the conditions for extracting a natural pigment from walnut green husks were explored: extracting the pigment by ultrasonic extraction under suitable conditions, and then the pigment was separated out with adding acid, dried for powder. Content of tannin and flavonoids which were main dyeing composition were determined, and stability of the pigment was studied. The result showed that the average content of tannin and flavonoids were 28.07%, 4.86% respectively. The pigment was heat-resistant and lightfast. There was sediment when the pigment was in acid condition, and the color became darker in alkaline condition. H2O2 had a certain impact on the stability of the pigment while Na2SO3 had not. Na+, K+ had no significant impact on the color of pigment, but Ca2+, Al3+, Cu2+, Fe3+ could form the complex with the molecules of pigment.