There are a variety of different types of food products that are manufactured by the process known as extrusion. Generally, these food products will have a high starch content and include breakfast cereals and certain maize snacks. These products are made at high temperatures in conditions where there are low amounts of moisture. There are some cheese products that are also manufactured using extrusion.
The Extrusion Process and Outcomes
The extrusion process is a complicated one, but we’ll break down the basics of the manufacturing process.
The low moisture content of the materials along with the temperature and the speed of the flavour retention and structure of the corn grits which have been flavoured with isovaleraldehyde, ethyl butyrate and butyric acid has been investigated.
The high temperatures in extrudates which were more expanded, with the higher moisture content, increased the retention of ethyl butyrate. The best extrudates were those with a low moisture content, made under high temperature conditions and a high screw speed while those made with a low screw speed and lower temperatures had higher aromas.
This specific type of food extrusion process is using for mixing and compounding materials as well as reacting materials. The twin screw food extrusion equipment is highly flexible and is designed specifically for the task at hand. The twin screw food extrusion equipment can be used as kneading blocks or to provide for the specific mixing characteristics required.
About Cereal extrusion
Seeing as most cereals are very rich in starch, cereal extrusion is a common process. The starch, when in its natural state is tasteless, cannot be dissolved and is basically not fit for human consumption. In order to make it edible, the starch must first be cooked. Traditionally, the cooking of starch needs the right amount of time and needs to be done at the right temperatures. Just about any cereal can be cooked using an extruder, although its added shear to the product can have an impact on the quality.
If adding dimension to the product is the goal, then the number of cereals you can use are limited to rice and de-germinated corn or grit. Cereal with more lipids have difficulty expanding, so this kind of cereal will need a high moisture content and high temperature in order to become puffier. Starches with a 5 to 20% amylose content will give breakfast cereals a more expanded look and better texture.
Corn is one of the most commonly used starches for breakfast cereals
Corn snacks and breakfast cereals which have been extruded are becoming very popular. Corn, which is also known as maize, is used as the primary ingredient for corn collets and other pellet products. The majority of corn based breakfast cereals are made used dry-milled cornmeal. The large amounts of cornmeal are ideal for puffed snacks and breakfast cereals which some are used to make corn chips.
The different types of dry-milled dent corn include cornmeal, corn flour, corn cones and corn grits. These usually only differ in terms of particle size distribution. The type of granulation will depend on the product being manufactured.
For corn products that have a softer bite, and a finer cell structure, the fine granulation corn meal is ideal. If you are going for a crunchy product with a larger cell structure then it is best to go with a coarser granulation. The twin screw extruders can be used for both fine and coarse granulation while collet extruders are ideal for coarse granulation. De-germinated corn is used to make most breakfast cereals as well as snacks because it expands while whole corn does not.