Abstract:

The solvent extraction and stability of anthocyanins from the stems of Dendrobium devonianum grown in
Longling, Yunnan province, China were studied. The results showed that the absorption peak of the anthocyanins occurred
at 533.0 nm. Solubility and color tests showed that anthocyanins were the major components of the pigments extracted
from Dendrobium devonianum. The total contents of anthocyanin in purple sheath-type, purple strip-type and red core-type
Dendrobium devonianum were 39.65, 35.05 and 15.85 mg/L, respectively. The temperature to some extent had great effect
on the anthocyanins of Dendrobium devonianum. As the temperature rose, the color gradually deepened. When exposed
to sunlight, the anthocyanins were unstable extremely. Metal ions such as Mg2+ and Al3+ had hyperchromic and protective
effects on the pigments, while Cu2+, Zn2+ and Fe3+ could result in fading of the color accompanied with apparent precipitation.
Increasing concentration of H2O2, VC and Na2SO3 could accelerate fading. However, Na2SO3 exhibited a hyperchromic
effect on the pigments, but sucrose and citric acid could exert negative effects on the stability of the anthocyanins.

Key words: Dendrobium devonianum, anthocyanin, extraction, identification, stability