THE EXTRACTION OF COMMON FOUR-O' COLCK PIGMENT AND THE STUDY OF ITS STABILITY

To provide important raw material for all kinds of new pigment used in food products,cosmetic and leechdom etc.Study on the stability of red pigment from common four-o'clock and the condition of extraction.Ethanol was used as the extractant in the extraction,and the pigment stability was investigated by UV spectrum.The optimum condition for ethanol extraction is:65 % ethanol was used as the extractant(pH=3),and 1g material was extracted in 10 mL extractant under room temperature for 24 h.The λmax for the pigment was 440 nm,which has 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,has no effect on the stability of thepigment,while starch,(NH4)2S2O8(oxidant),vitamin C(reducing agent)and metallic ions have good effect on its stability.