The fat can be separated from fat-containing milk/milk powder through the addition of sulphuric acid. The separation is made by using amyl alcohol and centrifugation. The fat content is read directly on a special calibrated butyrometer.
- Total Fat by Gerber/Teichert method - GEA Niro Method No. A 9 b
- TCVN 5504:2010 - ISO 2446:2008.
The method is to be used for fat-containing milk powders.
- Balance - sensitivity ± 0,0001 g
- Special butyrometer - scale 0-35% or 0-70%.
- Caoutchouc stoppers.
- Pipettes – 1ml and 10 ml.
- Funke Gerber and rotor Hear A
- Water bath
- Sulfuric acid (H2SO4) – density 1.846 ± 0.003 g/ml 90-91% at 20oC.
- Amylalcohol (C5 H12O) ≥ 98%, density 0,811 ± 0,002 g/ml at 20oC.
- Distilled water.
6.1 Pour successively into the butyrometer:
- 10 ml sulphuric acid.
- 9 ml distilled water. (must not be mixed with the acid).
- Exactly 2.5g powder.
- 1 ml Amylalcohol.
6.2 Close the butyrometer with the caoutchouc stopper and shake untill the powder is dissolved. Turn the butyrometer upside-down 5 times.
6.3 Boil in water bath for 5 minutes at 65 ± 3o C.
6.4 Spin in the centrifuge for 5 minutes at 65 ± 3o C, (mode “Gerb”)
6.5 Shake for further 1 minutes. Turn the butyrometer upside-down 5 times. Spin in the centrifuge for 5 minutes at 65 ± 3o C, (mode “Gerb”)
6.6 Read result:
Adjust the fat colum by using the stopper, so that it will be in the graduated part of the butyrometer.
Fat content theory is read directly on the butyrometer.
Fat content theory:
+ A: Read a top fat column
+ B: Read a bottom fat column.
+ f: Fat content theory.
+ X(%): The fat percent.
+ m: Quantity sample