Any cereal can be used to suit local availability, with rice, wheat and oats being the most widely used. These products can be fortified with minerals and vitamins to suit local needs.
Manufacture of cereal-based products
The cereal component is either milled on site or purchased as a flour, and after screening it is mixed with water to produce a slurry. This mixing can be carried out either batchwise or continuously. If required, sugar and vegetable oil can be added at this stage of the process.
The slurry is passed through a scraped-surface heat exchanger to be pre-heated to at least 100°C. APV scraped-surface heat exchangers ensure the slurry is heated without coming into direct contact with steam. In this way, the solids content of the slurry is maintained and the possibility of contamination from the steam is removed.
Thermal pre-treatment is also used to remove some of the heat load from the drum dryer, so increasing the output of the line. Furthermore, it ensures that the starch component of the cereal is fully gelatinised, and it greatly reduces the microbiological load in the finished product.
Drying and mixing
Products are typically dried in a drum dryer. The hot, gelantinised slurry is distributed onto the main drum of the drum dryer, where the steam-heated surface dries the slurry to a film. This film is removed by a knife and collected in a screw conveyor, where the film is pre-broken to allow it to be pneumatically transferred to a milling system. The dried film is reduced to the required size in a cone mill. Minerals and vitamins can be added at this stage.
If no further ingredients are to be added, the film is ground to a fine flake. However, if further ingredients, such as milk powders, flavours, etc. are to be blended into the milled product, they are usually reduced in size to a powder to minimise possible separation of the different powders in transport.
Storage and packaging
At the end of the mixing cycle, the finished product can either be stored in bins or sent pneumatically directly to the packing hall.
Rusks and biscuits
Rusks and biscuits are a valuable source of nutrients and energy. For infants, the rusk can be dissolved by warm fluids, and can be fed as a liquid or porridge. For older children, it can be eaten as a biscuit or as part of a meal.
Manufacture of rusks and biscuits
The ingredients are mixed on high-speed mixers which provide fast and thorough incorporation of the ingredients, especially vitamins and minerals, and automatic discharge of the dough.
Forming and baking
After mixing, the dough is fed to the hopper of a special extrusion machine cut into pieces of the correct thickness.The rusks are baked gently and slowly on a steel conveying band. To ensure the correct texture and moisture content of the rusk, a special temperature profile and application of air turbulence and control of humidity are required. Ovens can be supplied for heating by gas, electricity and oil.
Cooling and packaging
Baked rusks are transferred from the oven band to a cooling conveyor where they are cooled slowly in ambient conditions allowing the moisture to equalise throughout the rusk.
The rusks are automatically stacked on a specially breakage and are then transferred to packaging machines.