Extraction and Stability of Pigment from Calendula officinalis L. Flowers

Objective:To obtain the optimum extraction conditions for pigment from Calendula officinalis L.flowers,and to study the stability of the pigment under various conditions.Methods:Solvent extraction was used to extract pigment from C. officinalis L.flowers.The effects of solvent type,material-to-liquid ratio,temperature and extraction time on pigment extraction(reflected by the absorbance at 466 nm of extracts)were studied.A L9(34)orthogonal array design was employed to optimize the extraction conditions.The stability of the pigment towards light,heat and food additives was also investigated by determining the change in absorbance at 466 nm.Results:The optimal extraction conditions for C.officinalis L.flower pigment were using 90%aqueous ethanol as extraction solvent for extraction at 70℃for 40 min with a material-to-liquid ratio of 1:8(g/mL).The pigment was stable under acidic(pH 5),light and heat conditions.Common food additives such as glucose and sucrose as well as some metal ions including Na+,Mg2+,Ca2+and Cu2+had no adverse effect on the pigment.However,Fe3+had a significant negative effect on the pigment.Conclusion:The optimal extraction conditions of pigment from C.officinalis L.flowers has been obtained. The pigment shows good stability toward light,heat and some common food additives,thereby having broad application prospects in the fields of food and drug.