Effects of physical and chemical factors on anthocyanin stability in Lycoris sprengeri

Abstract

Objective This study aims to investigate the composition of anthocyanins and the effects of physical and chemical factors on the stability of anthocyanins in Lycoris sprengeri. Method The anthocyanins in the flower were determined by liquid chromatography-mass spectrometry (LC-MS). The effects of temperature, light, pH value and metal ions on the color change of anthocyanins in L. sprengeri were studied by ultraviolet spectrophotometry and HPLC-ADA. Result (1) Cyanidin, pelargonidin and delphindin were the main components of anthocyanins in L. sprengeri. (2) The anthocyanin solution was stable when temperature was lower than 30 ℃, dark and pH value ≤ 3.0. High temperature, strong light and high pH value could degrade anthocyanins, and the degradation degree increased with time. Al3+, Fe2+, Cu2+ and Fe3+ all changed the color of anthocyanin solution, and Ca2+, Zn2+, Mg2+ and K+ had little effect on the color of anthocyanins, but the metal ion concentration of 0−0.01 mol·L−1 had a certain effect on the color of anthocyanins. Hyperchromic effect of Fe2+ was more obvious when Fe2+ concentration increased. (3) High temperature, strong light and pH value had some effects on the concentration of anthocyanins. The concentration of cyanidin 3-O-glucoside decreased with the increase of time, light and temperature, while that of pelargonidin-3-O-glucoside showed the opposite trend. Delphinidin-3-O-glucoside was stable under different light and temperature conditions. With the increase of pH value, the mass concentration of cyanidin-3-O-glucoside decreased gradually, while delphinidin-3-O-glucoside increased gradually. Conclusion The main components of anthocyanins in L. sprengeri are cyanidin, pelargonidin and delphinidin. High temperature, strong light and high pH value can degrade anthocyanins, which can lead to their structural transformation. [Ch, 7 fig. 1 tab. 29 ref.]