A Research of the Extraction and the Stability of Yellow Pigment From Longan Shell

In this thesis,we study the extraction and the stability of the yellow pigment from longan shell.The result of this experiment shows that the optimum extracting process is to use ethyl acetate with the tempera ture of 40 ℃,time for 3 hours and the ratio of raw materials1∶30.Stability research shows that the pigment has good lightfastness,thermal stability and reducibility stability.Food additives and metal ion have a little ef fect on the pigment.However,citric acid and potassium sorbate have sensitizing effect,so these food additives shouldn’t be used too much.What’s more,Fe3+、Zn2+ and Al3+have a greater influence on the pigment.The pigment shows strong acid resistance,but alkali resistance intolerance.When the pH is about 10,the colour of pigment changes obviously and has a small amount of sediment.