pigment yellow
4.The yellow-green globular material seen in small bile ductules in the liver here is bilirubin pigment.
9.After filtration with filter aid,the color of the oil without peculiar smell,no longer blistering and smoking,was yellow,its acid number was decreased from 1.12mgKOH/g to 0.12mgKOH/g,and more than 70% pigment and most of polar compounds in frying oil was gotten rid of. So filtration and purifying effect of the filter aid was obvious.

