Extrusion process is widely used in food processing. Various food items such as Cookie Dough, Sevai, Pastas, Breakfast Cereals, Idiappam, Jalebi, Fig Newtons, French Fries, Baby Food, Ready-To-Eat Snacks and Dry Pet Food are most commonly manufactured using the extrusion process. In this process, the raw materials are grounded to the exact particle size. The dry mix is then passed via a pre-conditioner, where addition of other ingredients takes place. These ingredients are dyes, meats, liquid sugar, fats and water. The addition of these ingredients is dependent on the product being manufactured and accordingly injection of steam may also take place for starting the cooking process.
The entire preconditioned mix then passes through an extruder, after which it is forced through a die, where desired length is obtained by cutting it. The cooking is done inside the extruder, where the product creates its own heat and friction because of the generated pressure (10–20 bar). The cooking process uses another process known as Starch Gelatinization. Extruder which use this process, generally have the capacity of 1 to 25 tonnes per hour, on the basis of its design. The extrusion Cooking Process provides following food advantages:
- Starch gelatinization
- Protein denaturation
- Inactivation of raw food enzymes
- Destruction of naturally occurring toxins
- Diminishing of microorganisms in the final product
Extrusion – New and Creative Food Items
Generally, extrusion is also called food processing in some segments. It basically includes food compression into a semi-solid mass, in the initial step and then forcing it through a small aperture in the next step to enhance the varieties of texture, color, and shape that can be acquired from basic food ingredients. Extrusion can form & even cook the raw ingredients into the finished products. Some of the important points related to extrusion of food items is as follows:
- The extrusion process can take place under high pressures and temperatures or it can be just an easy non-cooking, and forming process.
- Use of extrusion in food production mainly assists in preserving the food products. This process is used for controlling the ingredient’s water activity, which consequently determines the microbial growth and hence, its spoilage.
- Extrusion is used for making pet foods.
- With the extrusion process, most cereals and cereal-based products like breads, breakfast cereals & cakes can be processed.
- The extrusion processing is also used to prepare camping & military field rations, foods for feeding during disaster & famine recovery as well as for special dietary needs