In this discussion, we address another method of producing full-fat soybean, known as extrusion. Extrusion refers to a process where soybeans are subjected to high pressure and temperature, resulting in friction, pressure, and heat, which crushes the soybeans and produces extruded soybean.
During this operation, the moisture of the extruded product is maintained at a level necessary for the thermal process. Additionally, the availability of nutrients for livestock is increased by the splitting of the seeds due to pressure and the destruction of the plant cell walls.
While heat-processed soybean has high digestibility, research has shown that processing using the extrusion method can have even more positive effects on the quality of the product. The small particle size and direct contact with the heat source ensure that a product of consistent quality is produced throughout the process.
Although extrusion equipment is not particularly complex, it is expensive. The simplest and most economical type of extruder is known as the single screw extruder. The product coming out of this device requires regular analysis for anti-nutritional factors. If the raw soybean is heated before entering the extruder, the pressure required for extrusion is reduced, ultimately facilitating the operator's task.
The extruder device is also produced in a more complex model with two rotating screws (two-screw extruder). Due to its higher cost and greater complexity, this system is used in human food industries and in the preparation of feed for aquatic animals and pets.