by Dr Mian N Riaz, Director of Process Engineering at T&M University, US
The extruder is an ideal machine that was designed for processing floating or sinking aquatic feed by adjusting the formula. Extrusion requires moisture, heat, and pressure to process the aqua feed. Temperature higher than 100℃ are needed in order to achieve expansion of the aqua feed as it leaves the die.
In extrusion, the temperature is achieved through preconditioning and steam injection. At the same time the material also undergoes relatively high pressure. The pressure difference in the interior of extruder and the external environment will cause the extrusion of the aquatic feed. As the material is squeezed through die holes at the end of the extruder barrel, part of the water in the superheated dough immediately vaporises and causes expansion. During extrusion, high quality aqua feed pellets are made by the denaturing of proteins and gelatinisation of starches. The aqua feed manufacturing industry is widely recognised as one of the fastest expanding feed industries in the world.
Extrusion is not a new technology. Since extrusion technology began in 1948, the equipment to produce aquatic feeds may look different, but the principles of processing remain the same; we cook feed at high temperatures. When a company commits to extrusion technology, it can be assured that an extruder will last for more than 20-30 years if maintained properly. The decision on which extruder to buy is based on costs, support and commitment of the company. A typical aqua feed extruder consists of feeding devices, preconditioner, extruder barrel, die and cutter.
Feeding Devices (Feed Delivery System)
Essential to any extrusion operation are the feed delivery systems. Hoppers or bins are an integral part of a feeding device and are used to hold the dry ingredients above the feeders. These systems must be able to uniformly feed both a dry and/or liquid ingredient and blend of ingredients.
Preconditioner
The preconditioning step initiates the heating process by the addition of steam and water into the dry mash. Uniform and complete moisture penetration of the raw ingredients significantly improves the stability of the extruder and enhances the final product quality. The objectives of a preconditioning step are to continuously hydrate, heat, and uniformly mix all of the additive streams together with the dry recipe.
The preconditioning process is simple. Raw material particles are held in a warm, moist, mixing environment for a given time and then are continuously discharged into the extruder. This process results in the raw material particles being hydrated and heated by the steam and water in the environment.
Read more HERE.
The extruder is an ideal machine that was designed for processing floating or sinking aquatic feed by adjusting the formula. Extrusion requires moisture, heat, and pressure to process the aqua feed. Temperature higher than 100℃ are needed in order to achieve expansion of the aqua feed as it leaves the die.
In extrusion, the temperature is achieved through preconditioning and steam injection. At the same time the material also undergoes relatively high pressure. The pressure difference in the interior of extruder and the external environment will cause the extrusion of the aquatic feed. As the material is squeezed through die holes at the end of the extruder barrel, part of the water in the superheated dough immediately vaporises and causes expansion. During extrusion, high quality aqua feed pellets are made by the denaturing of proteins and gelatinisation of starches. The aqua feed manufacturing industry is widely recognised as one of the fastest expanding feed industries in the world.
Extrusion is not a new technology. Since extrusion technology began in 1948, the equipment to produce aquatic feeds may look different, but the principles of processing remain the same; we cook feed at high temperatures. When a company commits to extrusion technology, it can be assured that an extruder will last for more than 20-30 years if maintained properly. The decision on which extruder to buy is based on costs, support and commitment of the company. A typical aqua feed extruder consists of feeding devices, preconditioner, extruder barrel, die and cutter.
Feeding Devices (Feed Delivery System)
Essential to any extrusion operation are the feed delivery systems. Hoppers or bins are an integral part of a feeding device and are used to hold the dry ingredients above the feeders. These systems must be able to uniformly feed both a dry and/or liquid ingredient and blend of ingredients.
Preconditioner
The preconditioning step initiates the heating process by the addition of steam and water into the dry mash. Uniform and complete moisture penetration of the raw ingredients significantly improves the stability of the extruder and enhances the final product quality. The objectives of a preconditioning step are to continuously hydrate, heat, and uniformly mix all of the additive streams together with the dry recipe.
The preconditioning process is simple. Raw material particles are held in a warm, moist, mixing environment for a given time and then are continuously discharged into the extruder. This process results in the raw material particles being hydrated and heated by the steam and water in the environment.
Read more HERE.
The Aquaculturists
This blog is maintained by The Aquaculturists staff and is supported by the
magazine International Aquafeed which is published by Perendale Publishers Ltd
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