MANUAL DE INSTRUCCIONES
CÓDIGO 80187 REV D
01/2021
Pag.: 35
J
.P. SELECTA s.a.u.
Autovía A-2 Km 585.1 Abrera 08630 (Barcelona) España
Tel 34 937 700 877 Fax 34 937 702 362
e-mail: [email protected] - website: http://www.grupo-selecta.com
Almonds 5,18
Nuts 5,30
Nut-peanuts, nuts Brazil 5,41
Jello 5,55
Soya 5,71
Cebada, avena, centeno 5.83
wheat, whole flour 5,83
Flours (except the whole) 5,70
Rice 5,95
Corn 6,25
All the other foods 6,25
Saved 6,31
Milk and milky products 6,38
Main protein factors
6.3 Distillation.
Please follow these steps (on the same order as indicated):
• Open the safety door.
• Place an Erlenmeyer flask with around 25ml with some drops of indicator mix
under the cooler output.
Check the tube output is immersed under the Bo
-
ric’s level.
• Insert the sample tube.
• Pre-select the NaOH volume.
• Push «START»
• If necessary, more NaOH could be added to the sample by pressing «NaOH»
button.
Visual Checking:
When the NaOH volume is sufficient, the sample becomes blue.
(If not, add more NaOH)
• Once 200ml of distillate are obtained on the Erlenmeyer (50ml Boric + 150ml
of distilled press «START» button to stop the distillation.
• Open the safety door.
• Remove, first, the sample tube.
• Remove the Erlenmeyer. (wait drip)
6.4 Titration
Prepare the titration burette with the reagent usually HCl 0.25N.
Slowly dispense the HCl 0.25N on the Erlenmeyer stirring it at the same time.
Titrate until the colour changes (end point at pH 4.65).
6.5 Protein contents (%) calculation.
From the HCl volume (ml) consumption on the titration the Kjeldahl Nitrogen (mg)
is calculated:
Nitrogen (mg) = 14 x Volume
HCl
(ml) x Normality
HCl
And, from the nitrogen we calculate the sample protein content:
Check the tube output is inmersed under
Boric’s level.
% Protein =
P
2
x 100 x F
P
0
P2: Nitrogen (mg).
P0: Sample weigth (mg).
F: Protein factor.
