Page 85 - Feed Lab

Suguna Management System Ver 1.0 / SOP / FQL / P2 - 12 Page 1 of 1

12. Estimation of Soluble Protein

PRINCIPLE
The sample is solubilized with potassium hydroxide
and the aliquot portion of the extract is subject to acid
digestion as usual. The digested extract is done as per
the SOP of crude protein distillation.

PROCEDURE
FWeigh 1.5 g of ground Soya sample in 250ml
Picture - 3 Picture - 4
conical flask or beaker. Add 75 ml of 0.2 % KOH
(0.036 N, pH -12.5, 2.36 g KOH/Liter) to this flask.
(Picture - 1)
FStir on magnetic stirrer to exactly 20 minutes
continuously and filter through cotton. (Picture - 2)

FCentrifuge 10 minutes @ 2700 rpm in the
laboratory centrifuge. (Picture - 3)
FPipette 25 ml aliquot from the centrifugate to the Picture - 1 Picture - 2
digestion tube and carry out as it for the crude
protein estimation. (Picture - 4) Note: Particle size of the sample should be uniform.
Stirring time and speed should be uniform. Titre value
for micro and macro Kjeldhal method is (B-TV).
CALCULATION
Effective weight: 25/75 = 0.3333 X sample weight (1.5 g) = 0.5 g
TV X 1.401 X 6.25 X N of Hcl
KOH Solubility % = ----------------------------------------
Effective weight, g

KOH solubility
Soluble protein % = ---------------------------- X 100
Crude Protein

Prepared by : Approved by :
73 Director - Technical