(i) Demineralisation of fish scales: The dried fish scales
was demineralised with hydrochloric acid solution (1.0
M) at room temperature with constant stirring for 2 hours,
using a ratio of solid to acidic solution of 1:13 (w/v),
when the fish scales became quite squashy. Then those
were rinsed with distilled water to remove acid and salt.
The decalcified product was washed with methanol and
acetone. The washed material was transferred to glass
tray, and dried for overnight at 60°C in an oven.