Analysis on stability and antioxidant capacity of color-related components from Dendrobium officinale flower

Abstract

The study is aimed to fully analyze antioxidant activty and stability of color-related components from Dendrobium officinale flower. The contents of anthocyanins,carotenoids and flavonoids of 10 varieties including whole flower and labellum of D.officinale flower were detected using UV visible spectroscopy technique and evaluated for their 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·), superoxide anion radical (·O⁻₂) and hydroxy radical (·OH) scavenging activty. And the effects of 4 kinds of metal ions (Cu²⁺, Mg²⁺, Al³⁺,K⁺) and 2 kinds of food additives were investigated on the stability of anthocyanins pigment from D.officinale flower. The results indicated that the flower of D.officinale contained anthocyanins,carotenoids and flavonoids,and their contents in different parts of different families varied. The content of anthocyanins (1 330.9 μg·g⁻¹) in labellum was significantly higher than that in the whole flower (696.3 μg·g⁻¹). The content of carotenoids was positively correlated with the content of anthocyanins,and there was significant positive correlation between the scavenging capacities of the three free radicals and the contents of anthocyanin,respectively (0.415,0.384,0.455). The Cu²⁺, Mg²⁺, Al³⁺, K⁺ and glucose showed significant color-enhancing effect and could increase the stability of anthocyanin in D.officinale flower,while ascorbic acids showed remarkably degradation effect of anthocyanin in D.officinale flower.