Rennet test (kazeinowa) aims to determine the ability of milk to clot under the influence of rennet and to learn about the firmness and contractility of the curd. Its implementation is as follows: 50 cm3 of milk is heated to 35 ° C and seasoned 1 cm3 rennet with a capacity of 1:100. Twice the practical amount of rennet would be obtained, if it gets diluted 1 cm3 rennet extract with a capacity of 1:10 000 water in quantity 100 cm3. After 10 do 20 minutes for normal milk to clot, previously sour, and the milk is alkaline, preserved with baking soda, watered down, when cooked, it will not solidify until after 20 minutes, or it will remain liquid.
Fermentation and rennet test. The rennet test described above allows us only to determine the solidification capacity under the influence of rennet. However, no inference can be made from it, cheese made from such milk behaves approximately, especially in the first stage of the transformation of milk sugar. The fermentation-rennet test makes the casein test superfluous and gives more. Its implementation is as follows.
The sterilized test tubes are used for 40 cm3 of milk and after 2 cm3 of rennet prepared from a small tablet of Hansemi (0,5 g) dissolved in 500 cm3 of pure water with addition 2 teaspoons of table salt. The seasoned and mixed sample is annealed at 38 to 40 ° C by 12 hours, followed by evaluation.
The cheese should be elongated into a rod, firm, smooth on the surface, and in the longitudinal section with little or no meshes. Whey should be clear and smell clean. Twisted cheese is considered more or less defective, erected, spongy, too hard in the flesh, pulpy, frayed. Observation of the acidification process enables the determination of the acidity of the whey. This test can also be combined with the reduction test by adding 1 cm3 of methylene blue, before renneting it. When there are no Hansen pills, you can make yourself a suitable solution of rennet taking 1 cm3 of liquid rennet with a power of 1 : 10 000 and diluting it 250 cm3 of water. This solution gives 1 cm3 do 40 cm3 of milk and gets a clot after 30 minutes, as long as normal milk is used.