Casein

1
Casein
2

• Rennet casein
• Plastics
• Processed cheese
• Acid casein
• Paper manufacture
• Paint, cosmetics
• Sodium or calcium caseinate
• Emulsifier in cured meats
• Milk and cream substitutes
• Calcium coprecipitate
• Nutritional purposes

3

• Raw material
• Skimmilk
• Excessive heating
• protein denaturation
• browning
• High bacteriological quality
• Microfiltration (fat removal)

4

• Rennet casein
• Pasteurization
• Renneting (30C) gelation (15-20 min)
• Heating (60C, 30 min)
• Draining
• Washing (45-60C)
• Removal of water
• Drying (50-65C, 12 water)
• Grinding
• Insoluble in water
• calcium paracaseinate, calcium phosphate
• high ash

5

• Acid casein
• Preheating 32C
• Acidification pH 4.6
• By presence of salt, 4.0-4.8
• Culture, HCl, H2SO4
• Heating 40-45C
• Draining
• Removal of water
• Drying (50-65C, 12 water)
• Grinding
• Insoluble in water

6

• Coprecipitate
• Addition of CaCl2 or acid
• Heating 85-95C, 1-20 min
• Precipitation
• CaCl2
• Dilute acid
• Washing
• Drying
• Or dissolving in alkali to increase dispersibility

7

• Sodium caseinate
• Wet acid casein curd or dry acid casein
• Addition of water 25-30 solids, 45C
• Grinding
• reduce dissolving time
• Addition of alkali
• 2.5 M NaOH, pH 6.7
• 1.7-2.2 of casein solids
• Sodium bicarbonate, sodium phosphates
• Dissolving 60-75C, 30-60 min
• High viscosity, maximum 20 solution
• Drying
• Minimise viscosity by preheating to 90-95C
• soluble in water

8

• Calcium caseinate
• Slower reaction
• Casein dissolved in ammonia
• Ca(OH)2 in sucrose added
• Drying
• Remove ammonia
• Magnesium, aluminium, silver, mercury, iron,
  copper caseinates
• Extruded sodium caseinate
• limited amount of water

9
Functional properties

• Solubility
• Gelling
• low pH
• high Ca2
• Swelling
• water retention
• casein high pH, low Ca2, low T
• denatured whey proteins
• Viscosity
• protein concentration, swelling, aggregation

10

• Emulsification
• Soluble proteins
• pH, ionic strength, specific salts, temperature
• aggregation
• Na-caseinate, whey proteins
• Foaming
• high viscosity
• Na- or K-caseinate
• whey proteins
• whey proteins heat denatured at high pH