A Mini-extruder is a miniaturized extruder to “cook” oil-seeds or kernels by creating friction with use of mechanical energy. The Mini is a single-screw machine that grinds the seeds which creates friction and cooks the seeds. The Mini-Extruder is driven by a 7.5 HP motor and can process about 40-50 kg of whole soybeans per hour. While the machine can process many types of oil-crops and grains, the capacity depends upon the bulk-density, moisture and oil content, and the desired temperature profile.
Soybeans or other seeds are processed in an extruder to produce extruded or “cooked” meal. The extruder does not typically remove any oil; hence, the extruded meal is called “Full-Fat” meal. The “Full-Fat” meal contains protein, fiber, moisture and oil.
Oil can be expelled from the seeds or extruded meal by using a mechanical press as explained later. When oil is removed, the meal becomes more protein and fiber-rich. It still contains some oil; hence, expelled meal is called “Partially defatted” meal.
What is the need for Extrusion?
Oil seeds and kernels are heated for two reasons. First, to reduce or destroy certain “allergens” or “enzymes” which are offensive or undesirable for human and animal consumption. Conventional methods of heating seeds involve steam-cooking or roasting. In addition, such methods require elaborate array of equipment and space. Extruder uses mechanical energy to create heat rather than subject the seeds to direct contact with steam or indirect heat. By avoiding steam or heat, the extruder operation is clean, convenient, and efficient. Depending upon the requirement, an extruder can be employed to rupture oil-cells in oil-seeds and kernels so that the oil can be pressed easily. An extruder can also be used to blend two or more grains, oil-seeds, or other ingredients to cook them into ready-to-eat food preparations.