The powder was stinging stirred with minimum amount of
water and the foam formed on the surface of the water was
collected and stored. The concentrated extract was made into
a solution with ammonium sulphate (20 wt%). The fibres were
treated under refluxing and kept at 80 ◦C for 3 h and again for
another two weeks at room temperature to ensure the complete
reaction between the fibres and the saponin extract. The ammonium
sulphate was removed with filtration followed by repeated
washing with distilled water. The absence of ammonium chloride
was confirmed by adding lead chloride to the filtrate until it gives
no precipitation of lead sulphate. After then, the modified samples
were dried in an oven at 45 ◦C.