In the production of natural curd cheese, milk is acidified through the addition of rennet or the action of lactic acid bacteria. For purposes of this experiment, students lower the pH by adding acid. As a result, the main protein fraction of the milk, the casein, flocculates and can be separated by filtration. This so-called 'curd' is the starting material for the production of cheese. The whey proteins retained in the filtrate can also be precipitated out through subsequent heating. The Biuret reaction is used to identify both precipitates as proteins.
| Materiallist (Excerpt) |
Product |
Amount |
|
Support base variable
|
02001-00
|
1
|
|
Bunsen burner /DIN/,nat.g.,w.cock
|
32168-05
|
1
|
|
Nitric acid , 65% 1000 ml
|
30213-70
|
1
|
|
Acetic acid 99...100%, pure 1 l
|
31301-70
|
1
|
|
Ammonia solution, 25% 1000 ml
|
30933-70
|
1
|
|
Ring with boss head, i. d. = 10 cm
|
37701-01
|
1
|
|
Boiling beads, 200 g
|
36937-20
|
1
|
|
Support rod, stainless steel, l = 600 mm, d = 10 mm
|
02037-00
|
1
|
|
Test tube rack for 12 tubes, holes d= 22 mm, wood
|
37686-10
|
1
|
|
Universal clamp
|
37715-00
|
1
|
|
Boss head
|
02043-00
|
1
|
|
Safety gas tubing, DVGW, sold by metre
|
39281-10
|
1
|
|
Dropping pipette with bulb, 10pcs
|
47131-01
|
1
|
|
Indicator paper, pH1-11, roll
|
47004-01
|
1
|
|
Protecting glasses, clear glass
|
39316-00
|
1
|
|
Concertina filter,d 240mm, 25 pcs
|
32979-04
|
1
|
|
Glass beaker DURAN®, short, 400 ml
|
36014-00
|
3
|
|
Rubber gloves, size 8.5
|
39323-00
|
1
|
|
Graduated cylinder 100 ml
|
36629-00
|
1
|
|
Test tube, 18x188 mm, 10 pcs
|
37658-03
|
1
|
|
Funnel, glass, top dia. 80 mm
|
34459-00
|
1
|
|
Spoon, special steel
|
33398-00
|
1
|
|
Wire gauze 160 mm x 160 mm, ceramic cen.
|
33287-01
|
1
|
|
Glass rod,boro 3.3,l=200mm, d=5mm
|
40485-03
|
1
|
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