Crude fiber was determined according to AOAC (1990), 2g of
defatted sample were treated successively with boiling solution of H2SO4
and KOH (0.2 and 0.28 N, respectively). The residue was then separated
by filtration, washed and weighed and then washed and transferred into a
crucible then placed into an oven adjusted to 105o
C for 18 – 24 h. The
crucible with the sample was weighed and ashed in a muffle furnace at
500o
C and weighed. The crude fiber was calculated using the following
equation: