Characteristics of Gynura bicolor DC. Color and Its Applications as a Novel Natural Food Color

Abstract

The reddish purple color of the abaxial side of Gynura bicolor DC. leaves is known to be anthocyanins. We previously isolated two novel poly-acylated anthocyanins, bicolnin and bicolmalonin from G. bicolor leaves and determined there chemical structures. In the present study, we evaluated the effects of light, heat, pH and metal ions on the stability of G. bicolor pigment to estimate its utility. Our evaluation results revealed that G. bicolor pigment showed significantly higher stability than such food colors prepared from red cabbage, red perilla and purple sweet potato. Furthermore, G. bicolor pigment didn’t show mutagenicity by the reverse mutation test. The application test of G. bicolor pigment as beverage also showed high stability. We concluded from these results that G. bicolor pigment is a useful novel natural food color having high stability and safety.