The research of the extraction and the stability of Rubus parvifolius red pigment

Rubus parvifolius red pigment is a kind of natural edible pigment extracted from Rubus parvifolius berries.This article researched on the stability of the red pigment.,which shows the best extraction technology is 1.5% hydrochloric acid-ethanol,70 ℃,6 hours and the ratio of raw materials 1∶700.Stability research shows that the red pigment has fine heat stability and reducibility stability.Sunlight has a great impact on the pigment,so in the process of storage it should be avoided direct sunlight.Common food additives,including sugar and sodium benzoate,citric acid,potassium sorbate,xylitol,cyclamate and saccharin,have little negative effect on the red pigment.However,because ascorbic acid has a slight impact on it,this food additive shouldn't be used too much.Fe3+,Cu2+ have greater influence on the red pigment than others including Zn2+,K+,Ca2+,Mg2+,Na+,Al3+ etc.In the test of acid and alkali tolerance,the pigment shows strong acid resistance and alkali resistance intolerance.When pH value is not more than 8,the pigment showed stable red;On the contrary,it showed stable light yellow.