LABEC M-MIA-A - Manual (Page 58)

Ultrasonic milk analyser
• Glasses from 25 till 50 сm 3 ;
• Centrifuge for Gerber;
• Water bath;
• Mercury thermometers up to 100 o С with value scale 1 o С;
• Sulphuric acid with density 1,82 at 20 o С for determination of fat content
of the milk;
• Isoamilic alcohol for Gerber with density 0,811 to 0,812.
2.5. Making the determination:
Preparation of samples for analyses.
The milk is mixed well in order to become homogenous mixture (if necessary
it is slowly heated up to 35-40
о С ) and is carefully shaken and tempered to
20±2 о С. The samples from whey and buttermilk are preliminary filtered
through double layer gauze and is then tempered to 20±2 о С. Cream samples
are placed in water-bath at temperature 35 till 40 о С, stirred till homogenous
sample is received and cooled down to 20±2 о С.
2.6. Making measurement
With butyrometer for milk
For milk, whey and buttermilk.
With automatic or special for acids pipette are measured 10 сm
3 sulphuric
acid with d=1,820 кg/m 3 at 20 о С in the milk butyrometer. Carefully on the
butyrometer's walls are piled up 11 сm 3 from the prepared sample. The
pipette is held till its full drainage.
For cream
From the prepared sample is measured 10 g with error up to 0,001 g and 50
сm
3 water are added. Mixture is well stirred and heated up to 30-35 о С, then
is again stirred and cooled down to 20±2 о С, and the following steps are as
with the milk sample using sulphuric acid with d=1,789 till 1,790 кg/m 3 .
With butyrometer for cream
For cream
5 g from the sample are measured with butyrometer with error up to 0,0001 g
and then 5 сm
3 water are added, 10 сm 3 sulphuric acid with d=1,780 to 1,790
кg/m 3 at 20 о С and 1 сm 3 изоамилов alcohol. The butyrometer is closed with
rubber stapple and is shaken till the proteins are fully dissolved.
2.7. Calculating the results
By using milk butyrometer
Milk, whey, buttermilk.
Using the butyrometer's graded scale the grams fat in 100 g product are read
directly. When the milk is curdled, the result is increased with 0,1 g for every
degree.
By using cream butyrometer.
Operation manual MRC.VER.01-02.10