Processing of Casein

Process description for the processing of Casein

The pasteurized skim milk or diluted concentrated skim milk is conveyed by the centrifugal pump from the  balance tank through the plate heat exchanger.

There the milk is heated up to a temperature of approx 30⁰C by the returning whey from the decanter. Afterwards whey will be cooled further down to approx. 10⁰C by water and ice water.

After that the skim milk is acidified to a pH – value of 4.55 by means of HCL dosing system.

After a short reaction time the acidified milk is heated up to a coagulating temperature in the tubular heat exchanger.

In the reaction section the casein grain are formed which are separated from the whey in the first decanter.

The discharged whey will cooled down by regenerative heat exchange in the first plate heater.

Further cooling of the whey to approx. 6⁰C will be done in the second section by using water and in the third section by using ice water.

The separated casein grain with approx. 40-42% DS falls directly into the washing tank where it is mixed with wash water which is discharged from the third decanter.

From there the casein water mixture will be transferred into the second decanter. The discharged casein particles enters now the second washing tank. There the casein is mixed with fresh hot demineralised water of approx. 95⁰C.

By means of this procedure the casein particles will be pasteurized in order to minimize the bacteria count.

The hot casein water mixture is cooled down to separating temperature in the tubular cooler.

After a short reaction time by passing through the reaction stage the casein water mixture will be lead into the third decanter.

The casein is concentrated to a DS of approx. 45-48% in the decanter.

By means of a pneumatic conveying system the casein is blown into the dryer.

 

2.1          Wash Water

Wash water is specified as per IDF Standard No. 117/1979

Initial pH                                  6.5 to 7.5

Total hardness max.               90mg/l (PPM) = 6⁰ DH = 1.78mVal/L

Free Chlorides            max                1.0 mg/L

Iron, max                                 0.2mg/L

Magnesium, max                    0.5mg/L

Temperature                           10 to 12 ⁰C

Pressure                                  4.0 bar

Wash water intake                  20% - 25% of the skim milk intake during production

3.0          PRODUCT SPECIFICATIONS (IDF)

1.    Specification of Acid Casein

	Acid Casein Edible Grade	Acid Casein Extra Edible Grade	Acid Casein First Grade Industry	Acid Casein Stand. Grade Industry
Moisture	12%	10% max	12%	12% max
Fat	1.75& max	1.5% max	1.75%	2% max.
Free Acidity, expressed as L. Acid	0.2% max.	0.2% max	0.3%	0.3%
Ash	2.2% max.	2.2% max	----	----
Protein (moisture free basis)	94%	95%	----	----
Lactose	0.3%	0.2%	----	----
Colour	White to pale cream	White to pale cream	White to pale cream
Penicillin	Negative	Negative	Negative	Negative
Phosphatase	Negative	Negative	Negative	Negative
SPC  TBS	30000 max/g	30000 max/g	-----	-----
Coliforms	Negative	Neg. in 0.1g	-----	-----
Yeast & Moulds	50 max/g	50 max/g	-----	-----
Thermophile	5000 max/g	5000 max/g	-----	-----
Pathogenic Organisms	Negative	Negative	-----	-----