Abstract:

The red pigments that were extracted from edible-leaf beet stems using 80% ethanol were subjected to spectral scanning in the wavelength range of 230－700 nm, and the influences of sucrose, pH value, temperature, reducer, oxidizer, light and metal ions on the stability of the red pigments were investigated. The results showed that the pigments had two peaks in the UV region, which were at 270 nm and 334 nm, respectively, and also had two peaks at 538 nm and 666 nm in the visible light region. The red pigments from edible-leaf beet stems was stable when heated for 30 min below 70 ℃, but it could not resist high temperature; the color of the red pigments was stable when pH was below 10; the pigments presented weak antioxidant capacity, and the color would fade when exposed to the natural light for a long time, while sugar had no obvious effect on it; and other metal ions such as Ca2+, Mg2+ and Zn2+ had no effects on it, except Fe3+ and Al3+ exhibiting hypochromic effect, while K+ and Na+ presenting hyperchromic effect.

Key words: edible-leaf beet, red pigments, stability