There are a great number of products manufactured in the milk powder industry including milk powders, modified milk powders, powdered milk by-products, and dried milk based products containing either milk solids only or also other foodstuff components. Therefore milk powder technology is a broad subject. The target of industrial production is to produce products which fulfil all the qualitative requirements. The influence of various technological parameters on powder properties is discussed in detail in section 10. Achieving product properties. This chapter presents just a survey of products with the required qualitative properties and technological guidelines for operation on various installations.
Milk powders are defined as follows:
a) Dehydrated products based on non-fat milk solids and milk fat, i.e. natural milk, the fat content of which has been adjusted by centrifugation or addition of cream or skimmed milk to achieve the fat content required in the final product. This is between 0.5 and 30% (expressed on total solids). Besides fat standardization, it is becoming more and more usual to standardize the protein content, i.e. to adjust it to a level of Frisian cows’ milk, i.e. 37-39% (total protein in non-fat solids) by means of the addition of lactose or permeate if the natural protein content of the milk supply is too high. Products involved in this group are skim milk and whole milk powders (designated often also as full cream milk powder) defined as milk powder with max. 1% fat and min. 26% fat respectively. Occasionally there are produced also powders with other fat content such as half cream milk powder with 14% fat or even others with a fat content inbetween these figures. Another product of this group is cream powder with a fat content 35-80%. Permitted additives are the vitamins in various forms and some minerals.
b) Fat filled milk powders based on skim milk and vegetable or animal fat, possibly a mix of those, with a fat content 10-80%. Beside the components and additives mentioned above, other functional additives are used such as emulsifiers, stabilizers, flavouring and colouring agents etc.
The inlet air temperatures as stated for the individual products in the subsequent text are valid at normal ambient conditions, i.e. with absolute air humidity max. 7 g/kg dry air. Higher air humidity will require reducing the inlet air temperature, (equal to reducing the evaporative capacity of a given dryer) or dehumidifying the air.
Similarly, the feed concentrations are valid for milk of normal composition with max. 39% proteins in non-fat solids. Higher protein content requires reducing the concentration or standardizing with lactose or permeate to keep the viscosity below 100 cP at 40°C.
Regular milk powders
Regular skim milk powder
Process or system | Atomization | Inlet temperature °C | Concentration %TS | Bulk density g/cm3 | Relative heat consumption |
---|---|---|---|---|---|
Single stage Single stage Two stage Two stage Compact Compact MSD |
nozzle wheel nozzle wheel nozzle wheel nozzle |
180 180 200 200 220 220 240 |
45 48 47 50 47 50 47 |
0.75 0.68 0.78 0.72 0.78 0.72 0.66 |
1.00 0.97 0.77 0.74 0.84 0.79 0.79 |
Regular whole milk powder
Process or system | Atomization | Inlet temperature °C | Concentration %TS | Bulk density g/ cm3 (1250) | Relative heat consumption |
---|---|---|---|---|---|
Single stage Single stage Two stage Two stage Compact Compact MSD |
nozzle wheel nozzle wheel nozzle wheel nozzle |
160 160 200 200 220 220 240 |
45 48 47 50 47 50 47 |
0.64 0.60 0.66 0.64 0.66 0.64 0.62 |
1.00 0.97 0.74 0.71 0.88 0.83 0.83 |
Whole milk powder with high free fat content
Butter milk powder
Sweet butter milk powder
Acid butter milk powder
Fat filled milk powder




Agglomerated milk powders
Agglomerated skim milk powder
- Inlet air temperature for single stage processing in a conventional and TALL FORM DRYER™ with cooling bed 180°C, for two stage drying in conventional, TALL FORM DRYER™ and COMPACT DRYER™ 200°C, for Multi Stage Dryer, MSD™ up to 240°C,
- Feed concentration for pressure nozzles and wheel atomizer 48-50%. All other requirements to the skim milk concentrate similar to what is mentioned in 8.1.1., however the WPNI should be between 2.5 and 3.5 mg.
Agglomerated whole milk powder
- Inlet air temperature for single stage process in conventional and TALL FORM DRYER™ with cooling bed 180°C, for two stage drying in conventional, TALL FORM DRYER™ and COMPACT DRYER™ 200°C, for Multi Stage Dryer, MSD™ up to 220°C,
- Feed concentration for pressure nozzles and wheel atomizer 48-50%, homogenization,mpreferably two stages at 80 bars for first stage and 30 bars for second stage.
Instant whole milk powder
- standardization of fat,
- standardization of protein content by addition of lactose solution or milk permeate to 37-39% (on non-fat-solids),
- fortification with vitamins. Addition can take place as batch dosing in the standardization tank, or continuous dosing at the inlet to the evaporator or after pasteurization prior to the first evaporator stage. However, vitamin C in the form of ascorbic acid solution has to be added to the cold milk. In batch processing addition has to be carried out slowly under good agitation. In continuous processing, dosing is done preferably into the milk pipeline of good flow capacity. This is important, because it is an acid and poor mixing can cause local over-acidification and consequently precipitation. Another way to overcome these problems is buffering of ascorbic acid solution by sodium citrate or using ascorbic acid palmitate.
- Pasteurization in the evaporator at 85-95°C with 0-180s holding, resulting in WPNI 2.5-3.5 (consult 10.7.4. Heat stability),
- Homogenization two stage using 80 bar in first stage and 30 bar for the second stage,
- Inlet air temperature for two stage drying in Conventional, TALL FORM DRYER™ and COMPACT DRYER™ 180°C, for Multi Stage Dryer, MSD™ up to 220°C,
- Feed concentration for pressure nozzles and wheel atomization 48-50%,
- Lecithin treatment using powdered lecithin dissolved in butter oil in 25-50% solution and dosing rate to get 0.15-0.25 lecithin on powder. The temperature of lecithin solution must be 60-65°C. The lecithin treatment in two stage drying systems is done usually between the two fluid beds. In the Multi Stage Dryer, MSD™ or the COMPACT DRYER™, the lecithination is done at the outlet from the static fluid bed just above the first section of an external fluid bed,
- After lecithination, the powder has to be fluidized using warm air to keep the temperature well above 40°C, preferably 45°C,
- The final powder is collected in tote bins or similar containers or conveyed to silos and kept at the above temperature until filling into tins or bulk transport containers,
- The lecithinated whole milk powder has to be gas packed under inert gas, usually nitrogen in mixture with carbon dioxide to achieve residual oxygen content less than 2%. Otherwise the technological conditions for the production of instant whole milk powder can be found in Fig. 7.5. and the quality specification in Fig. 7.4.

Agglomerated fat filled milk powder
Instant fat filled milk powder
Whey and whey related products
Whey | Sweet | Acid | ||||
---|---|---|---|---|---|---|
Component | Liquid | Solids | Powder | Liquid | Solids | Powder |
Water Lactose Protein Minerals Fat |
94,00 4,550 0,80 0,60 0,05 |
0,00 75,84 13,33 10,00 0,83 |
2,50 73,94 13,00 9,75 0,81 |
94,10 4,00 1,10 0,75 0,05 |
0,00 67,80 18,64 12,71 0,85 |
1,50 66,79 18,36 12,52 0,83 |
Total | 100,00 | 100,00 | 100,00 | 100,00 | 100,00 | 100,00 |
Ordinary sweet whey powder
Ordinary acid whey powder
Non-caking sweet whey powder
Non-caking acid whey powder
Fat filled whey powder
Hydrolysed whey powder
Whey protein powder

Permeate powders
Mother liquor
Other Dried Milk Products
Baby food
Cow’s milk | Human milk | |||
---|---|---|---|---|
Component | Liquid | Solids | Liquid | Solids |
Water Fat Lactose Casein Lactalbumin Minerals |
87,35 3,75 4,85 2,78 0,47 0,80 |
0,00 29,64 38,34 21,98 3,72 6,32 |
87,30 4,10 6,90 0,60 0,90 0,20 |
0,00 32,38 54,34 4,72 7,09 1,57 |
Total | 100,00 | 100,00 | 100,00 | 100,00 |
- to operate non-stop for as long as possible, usually one week and then wet wash the installation after each stop of production,
- to operate non-stop for as long as possible but to use dry cleaning only, i.e. never water.
Caseinate powder
Component | Na-caseinate | Ca-caseinate |
---|---|---|
Protein Ash Lactose FatMoisture pH |
85.5 4.5 4.01.5 4.5 6.5-7.2 |
86.2 3.8 3.5 1.5 5.0 6.6-7.5 |
Coffee whitener
Component | |||||
---|---|---|---|---|---|
Corn syrup solids Fat (vegetable) Emulsifier (1) Stabilizer (2) Moisture Sodium caseinate Sucrose Flavour and colour Stabilizing salts (3) |
46.0 46.0 5.0 1.0 1.1 - - traces 0.9 |
13.5 54.0 2.7 0.8 3.7 11.0 13.5 traces 0.8 |
55-60 35-40 0.3 - 0.5 - - 4.5 - 5.5 - traces 1.2 - 1.8 |
- 1.0 - 12.0 - - - - 8.0 - 25.0 traces 0.5 - 1.0 |
54.0 36.0 - - 2.5 5.0 - traces 2.5 |
(1) Glycerol-mono-stearate, polyoxystearate, sorbitol-mono-stearate, Atmos 150/Span 60/Tween 60/20/20
(2) Carrageenin, alginate, guar gum.
(3) Sodium citrate, sodium phosphate, dipotassiumphosphate.
Coffee whiteners have to be well agglomerated, however without the presence of too large an agglomerate size, which otherwise will create so called floaters, appearing on the surface of the coffee as small lumps. The feed for spray drying is prepared by blending the components. Due to high content of malto-dextrin, the solids content of the feed can be rather high i.e. 64- 67%. Any type of two stage dryers with fines recycling, and spray dryers with integrated fluid beds can be used. The inlet air temperatures are 180°C (for MSD™ 220°C).
Cocoa-milk-sugar powder
Component | % |
---|---|
Cocoa Skim milk solids |
10-35 25-60 |
Cheese powder
Butter powder
İçindekiler tablosu
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1.Introduction
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2.Evaporation
- 2.1. Basic principles
- 2.2. Main components of the evaporator
- 2.2.1. Heat exchanger for preheating
- 2.2.1.1. Spiral-tube preheaters
- 2.2.1.2. Straight-tube preheaters
- 2.2.1.3. Preheaters to prevent growth of spore forming bacteria
- 2.2.1.3.1. Direct contact regenerative preheaters
- 2.2.1.3.2. Duplex preheating system
- 2.2.1.3.3. Preheating by direct steam injection
- 2.2.1.4. Other means to solve presence of spore forming bacteria
- 2.2.1.4.1. Mid-run cleaning
- 2.2.1.4.2. UHT treatment
- 2.2.2. Pasteurizing system including holding
- 2.2.2.1. Indirect pasteurization
- 2.2.2.2. Direct pasteurization
- 2.2.2.3. Holding tubes
- 2.2.3. Product distribution system
- 2.2.3.1. Dynamic distribution system
- 2.2.3.2. Static distribution system
- 2.2.4. Calandria(s) with boiling tubes
- 2.2.5. Separator
- 2.2.5.1. Separators with tangential vapour inlet
- 2.2.5.2. Wrap-around separator
- 2.2.6. Vapour recompression systems
- 2.2.6.1. Thermal Vapour Recompression – TVR
- 2.2.6.2. Mechanical Vapour Recompression - MVR
- 2.2.7. Condensation equipment
- 2.2.7.1. Mixing condenser
- 2.2.7.2. Surface condenser
- 2.2.8. Vacuum equipment
- 2.2.8.1. Vacuum pump
- 2.2.8.2. Steam jet vacuum unit
- 2.2.9. Flash coolers
- 2.2.10. Sealing water equipment
- 2.2.11. Cooling towers
- 2.3. Evaporator design parameters
- 2.3.1. Determination of heating surface
- 2.3.2. Heat transfer coefficient
- 2.3.3. Coverage coefficient
- 2.3.4. Boiling temperature
- 2.4. Evaporation parameters and its influrence on powder properties
- 2.4.1. Effect of pasteurization
- 2.4.1.1. Bacteriological requirements
- 2.4.1.2. Functional properties of dried products
- 2.4.1.2.1. Heat classified skim milk powders
- 2.4.1.2.2. High-Heat Heat-Stable milk powders
- 2.4.1.2.3. Keeping quality of whole milk powders
- 2.4.1.2.4. Coffee stability of whole milk powders
- 2.4.2. Concentrate properties
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3.Fundamentals of spray drying
- 3.1. Principle and terms
- 3.1.1. Drying air characteristics
- 3.1.2. Terms and definitions
- 3.1.3. Psychrometric chart
- 3.2. Drying of milk droplets
- 3.2.1. Particle size distribution
- 3.2.2. Mean particle size
- 3.2.3. Droplet temperature and rate of drying
- 3.2.4. Particle volume and incorporation of air
- 3.3. Single-stage drying
- 3.4. Two-stage drying
- 3.5. Expansion of air bubbles during drying
- 3.6. Extended Two-stage drying
- 3.7. Fluid bed drying
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4.Components of a spray drying installation
- 4.1. Drying chamber
- 4.2. Hot air supply system
- 4.2.1. Air supply fan
- 4.2.2. Air filters
- 4.2.3. Air heater
- 4.2.3.1. Indirect: Gas / Electricity
- 4.2.3.2. Direct heater
- 4.2.4. Air dispersers
- 4.3. Feed supply system
- 4.3.1. Feed tank
- 4.3.2. Feed pump
- 4.4. Concentrate heater
- 4.4.1. Filter
- 4.4.2. Homogenizer/High-pressure pump
- 4.4.3. Feed line
- 4.5. Atomizing device
- 4.5.1. Rotary wheel atomizer
- 4.5.2. Pressure nozzle atomizer
- 4.5.3. Two-fluid nozzle atomizer
- 4.6. Powder recovery system
- 4.6.1. Cyclone separator
- 4.6.2. Bag filter
- 4.6.3. Wet scrubber
- 4.6.4. Combinations
- 4.7. Fines return system
- 4.7.1. For wheel atomizer
- 4.7.2. For pressure nozzles
- 4.8. Powder after-treatment system
- 4.8.1. Pneumatic conveying system
- 4.8.2. Fluid bed system
- 4.8.3. Lecithin treatment system
- 4.8.4. Powder sieve
- 4.9. Final product conveying, storage and bagging-off system
- 4.10. Instrumentation and automation
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5.Types of spray drying installations
- 5.1. Single stage systems
- 5.1.1. Spray dryers without any after-treatment system
- 5.1.2. Spray dryers with pneumatic conveying system
- 5.1.3. Spray dryers with cooling bed system
- 5.2. Two stage drying systems
- 5.2.1. Spray dryers with fluid bed after-drying systems
- 5.2.2. TALL FORM DRYER™
- 5.2.3. Spray dryers with Integrated Fluid Bed
- 5.3. Three stage drying systems
- 5.3.1. COMPACT DRYER™ type CDI (GEA Niro)
- 5.3.2. Multi Stage Dryer MSD™ type
- 5.3.3. Spray drying plant with Integrated Filters and Fluid Beds - IFD™
- 5.3.4. Multi Stage Dryer MSD™-PF
- 5.3.5. FILTERMAT™ (FMD) integrated belt dryer
- 5.4. Spray dryer with after-crystallization belt
- 5.5. TIXOTHERM™
- 5.6. Choosing a spray drying installation
- 6.Technical calculations
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7.Principles of industrial production
- 7.1. Commissioning of a new plant
- 7.2. Causes for trouble-shooting
- 7.3. Production documentation
- 7.3.1. Production log sheets
- 7.3.2. General maintenance log book
- 7.3.3. Product quality specification
- 7.3.4. Operational parameter specification
- 7.4. Product quality control
- 7.4.1. Process quality control
- 7.4.2. Final quality control
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8.Dried milk products
- 8.1. Regular milk powders
- 8.1.1. Regular skim milk powder
- 8.1.2. Regular whole milk powder
- 8.1.3. Whole milk powder with high free fat content
- 8.1.4. Butter milk powder
- 8.1.4.1. Sweet butter milk powder
- 8.1.4.2. Acid butter milk powder
- 8.1.5. Fat filled milk powder
- 8.2. Agglomerated milk powders
- 8.2.1. Agglomerated skim milk powder
- 8.2.2. Agglomerated whole milk powder
- 8.2.3. Instant whole milk powder
- 8.2.4. Agglomerated fat filled milk powder
- 8.2.5. Instant fat filled milk powder
- 8.3. Whey and whey related products
- 8.3.1. Ordinary sweet whey powder
- 8.3.2. Ordinary acid whey powder
- 8.3.3. Non-caking sweet whey powder
- 8.3.4. Non-caking acid whey powder
- 8.3.5. Fat filled whey powder
- 8.3.6. Hydrolysed whey powder
- 8.3.7. Whey protein powder
- 8.3.8. Permeate powders
- 8.3.9. Mother liquor
- 8.4. Other Dried Milk Products
- 8.5. Baby food
- 8.6. Caseinate powder
- 8.6.1. Coffee whitener
- 8.6.2. Cocoa-milk-sugar powder
- 8.6.3. Cheese powder
- 8.6.4. Butter powder
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9.The composition and properties of milk
- 9.1. Raw milk quality
- 9.2. Milk composition
- 9.3. Components of milk solids
- 9.3.1. Milk proteins
- 9.3.2. Milk fat
- 9.3.3. Milk sugar
- 9.3.4. Minerals of milk
- 9.4. Physical properties of milk
- 9.4.1. Viscosity
- 9.4.2. Density
- 9.4.3. Boiling point
- 9.4.4. Acidity
- 9.4.5. Redox potential
- 9.4.6. Crystallization of lactose
- 9.4.7. Water activity
- 9.4.8. Stickiness and glass transition
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10.Achieving product properties
- 10.1. Moisture content
- 10.2. Insolubility index
- 10.3. Bulk density, particle density, occluded air
- 10.4. Agglomeration
- 10.5. Flowability
- 10.6. Free fat content
- 10.7. Instant properties
- 10.7.1. Wettability
- 10.7.2. Dispersibility
- 10.7.3. Sludge
- 10.7.4. Heat stability
- 10.7.5. Slowly dispersible particles
- 10.7.6. Hot water test and coffee test
- 10.7.7. White Flecks Number (WFN)
- 10.8. Hygroscopicity, sticking and caking properties
- 10.9. Whey Protein Nitrogen Index (WPNI)
- 10.10. Shelf life
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11.Analytical methods
- 11.1. Moisture content
- 11.1.1. Standard oven drying method (IDF Standard No.26-1964 [32])
- 11.1.2. Free moisture
- 11.1.3. Total moisture
- 11.1.4. Water of crystallization
- 11.2. Insolubility index
- 11.3. Bulk density
- 11.4. Particle density
- 11.5. Scorched particles
- 11.6. Wettability
- 11.7. Dispersibility
- 11.8. Other methods for determination of instant properties
- 11.8.1. Sludge
- 11.8.2. Slowly dispersible particles
- 11.8.3. Hot water sediment
- 11.8.4. Coffee test
- 11.8.5. White flecks number
- 11.9. Total fat content
- 11.10. Free fat content
- 11.11. Particle size distribution
- 11.12. Mechanical stability
- 11.13. Hygroscopicity
- 11.14. Degree of caking
- 11.15. Total lactose and α-lactose content
- 11.16. Titratable acidity
- 11.17. Whey Protein Nitrogen Index (WPNI)
- 11.18. Flowability (GEA Niro [31])
- 11.19. Lecithin content
- 11.20. Analytical methods for milk concentrates
- 11.20.1. Total solids
- 11.20.2. Insolubility index
- 11.20.3. Viscosity
- 11.20.4. Degree of crystallization
- 12.Troubleshooting operations
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References