Extraction and Stability Study on Euphorbia Thymifolia Red Pigment

The extraction condition from Euphorbia thymifolia and the stability of red pigment was studied.Ethanol was used as the extractant in the extraction,and the pigment stability was investigated by UV spectrum.The optimum conditions for ethanol extraction were: 65% ethanol was used as the extractant(pH=3),and 1g material was extracted in 10mL extractant under room temperature for 24h.The λmax for the pigment was at 440nm,which had good solubility in water,and excellent stability in the extractant(pH 1～9) for wide temperature scope,bad light resistance characteritics was observed,however.Some common food additive,such as cane sugar,glucose and salt,had no effect on the stability of the pigment,except for starch,(NH4)2S2O8(oxidant),vitamin C(reducing agent) and metallic ions.