SPX FLOW has extensive experience in the design and installation of APV systems for dairy-based baby foods and has process solutions for each particular product type, for example:
- Infant formulas as a substitute for human milk
- Follow-up formulas as part of the liquid diet of older infants
- Speciality formulas for specific nutritional needs
- Fermented baby foods SPX FLOW also has process solutions for a range of cereal-based baby foods, rusks, biscuits and "wet" baby foods containing meat, vegetables and fruit. These are described in the "Processed Food" section of this site.
Mixing and concentration
To obtain the correct composition of infant formulas, it is necessary to mix several ingredients prior to drying.
- The ingredients can be added wholly or partly
- before or after evaporation
- Amount of solids in the final concentrate varies from 45% to 60%
- SPX FLOW supplies APV tubular falling-film and APV plate evaporators for the concentration step. Evaporators are supplied with either thermal vapour recompression (TVR) or mechanical vapour recompression (MVR).
The main purpose of heat treatment is to obtain a product with a high bacteriological standard. The heat treatment may be either a mild pasteurisation, depending on product type and stage in the manufacturing process. Selecting the right heat treatment depends on a careful evaluation of the balance between high bacteriological quality and low destruction of valuable nutrients.
SPX FLOW specialises in heat treatment plants that provide a combination of gentle heat treatment and minimal influence on the nutrient content. This means that even heat-sensitive ingredients such as vitamins can be added before evaporation and drying.
- APV plate heat exchangers
- APV tubular heat exchangers
- APV scraped-surface heat exchangers
- APV infusion steam heating
- APV injection steam heating systems
The most efficient and nutritionally most gentle equipment from a bacteriological standpoint is the infusion steam heating system. This system is capable of operating at up to 150c, with a holding time down to fractions of a second.
Drying takes place in a spray dryer system. The concentrate is atomised to droplets, using either a centrifugal or a nozzle atomiser, and it is then dried by hot air.
For the manufacture of infant formulas, SPX FLOW recommends three types of plants:
- three-stage conical spray drying plant
- spray bed dryer with or without high-pressure air broom
- a combination of these with a rewet agglomerator system (two-stage agglomeration process)
Three-stage conical dryers with bottom outlet and integrated and external fluid beds are suitable for the manufacture of both non-agglomerated and agglomerated formulas. Spray bed dryers are suitable for manufacture of agglomerated formulas.
To minimise the need for cleaning, our plants can be supplied with an efficient high-pressure air broom, which reduces the powder deposits in the dryer, achieving prolonged running times.
Two-stage agglomeration with a spray dryer andagglomerator is described in more detail in the section on agglomeration below.
Some infant formulas are made by dry mixing of the ingredients. Usually, a basic powder is produced, representing 70-80% of the final product, and subsequently the remaining 20-30% is incorporated using a dry mixer.
Agglomerated powders are easier to dissolve in water and have become very popular in recent years.
SPX FLOW manufactures plants that can produce either non-agglomerated or agglomerated formulas. We have also developed and patented a process for drying and agglomerating infant formulas that gives excellent instant powder properties while minimising heat damage. The process is achieved by combining a spray dryer and a rewet agglomerator.
Manufacture of follow-up formulas
The manufacturing process for follow-up is very similar to that used for infant formulas including use of the same type of evaporators and spray dyers. The processing differences are dictated mainly by the higher content of proteins. This typically necessitates a reduction in the solids content of the concentrate in order to obtain the optimum viscosity for atomisation of the products. However, spray drying is generally easier because of the higher protein content.
Manufacture of speciality formulas
As mentioned above speciality formulas make up a large group, of varying composition. They typically contain starch, hydrolysed protein and maltodextrin but no milk ingredients. The most important processing differences is the wet mixing process. Depending on the ingredients used, it may be necessary to use special tanks with heavy-duty mixer equipment. Because of the spray drying process and the required powder properties, the viscosity of the concentrate has to be below a certain limit. Therefore it may be necessary to adjust the solids of the final concentrate accordingly. Although all the drying systems discussed above can be used to dry speciality formulas, the spray bed type with an air broom is especially suitable.
Fermented baby foods
Fermented milk products contain probiotic bacteria, which have a positive influence on the digestion of other food products.
The basic manufacturing principle for these fermented products is that all raw materials are UHT treated. In the subsequent processing, the products are treated as UHT products in an aseptic filling machines via fermentation tanks, coolers and buffer tanks. The starter cultures are dosed aseptically, just before the fermentation tanks.
The raw materials for these products are a mixture of whole milk, starter cultures, cream, corn oil, vitamins, minerals and various sugars.
When fermented dry infant formulas are produced, the basic mix can be UHT-treated, concentrated in an evaporator and inoculated with starter cultures just prior to spray drying. The final powder will then contain live bacteria.
Process Diagram and Benefits
- SPX FLOW specializes in APV heat treatment systems which provide a combination of high bacterial destruction with gentle treatment and minimal influence on nutrient content.
- To minimise the need for cleaning, our plants can be supplied with an efficient high pressure air broom which reduces powder deposits in the dryer, thus achieving longer run times.
- SPX FLOW's patented process for drying and agglomeration of infant formulas, gives excellent instant powder properties whilst minimising heat damage.
- SPX FLOW's global experience as a supplier of processing technology and equipment for dairy products is a key factor in our ability to deliver cost-effective solutions tailored to individual customer requirements.
- SPX FLOW offers an enormous range of resources to the dairy industry in process engineering, equipment manufacturing, project management - for both large and small projects - and world-class development facilities.