1. Feed Formulation: PQF Pellet quality factor
● Starch raw material: After hydrothermal gelatinization, starch raw material can provide a bonding effect for feed granulation.
● Protein raw material: Proteins undergo five main structural changes: unfolding, aggregation, binding, crosslinking, and degradation. Protein structural changes can affect functional properties such as solubility, viscosity and pellet feed quality. Heat treated protein has high plasticity and can be processed to produce pellet feed with a higher PDI. However, more than a certain amount of protein in the formula will affect the steam absorption of the feed. This will result in a lower PDI of pellet feed.
● Fat: Pellet feed with high fat content has low hardness, which leads to a high pulverization rate.
● Fiber: Fiber has an implicated role in the production of pellet feed with low crushing rate, high hardness; Fiber also has the effect of elasticity and water absorption expansion. If the fiber content in the formula is too high (more than 10% to 15%), it will cause feed is easy to break down to produce fine powder.
2.Grinding:
The finer the grinding particle size, the raw material surface area is improved, and the feed conditioning effect is better. With full contact with water and heat, the gelatinization and deformation of raw materials are good. The prepared particles have a high PDI, high hardness and a low pulverization rate.
3. Conditioning:
Conditioning refers to adding steam to the evenly mixed powder with hot water and softening the powder to make the nutrients in the feed more digestible and absorbed.
3.1 Tempering temperature:
Increasing tempering temperature can improve starch gelatinization degree, sterilization effect, feed productivity and finished products moisture, but the tempering temperature is too high on immunoglobulin, vitamins, enzymes and other heat-sensitive substances can produce negative effects result; Factors such as pressure, time and pH value of raw materials can change the structure and function of proteins.
4. Ring Die:
The ring die affects the degree of gelatinization, the hardness and powder percentage of starch feed. The smaller the diameter of the ring die, the larger the length-diameter ratio, the greater the hardness of the feed particles and the lower the pulverization rate.
5. Cooling:
The cooling process is one of the critical processes in pellet feed manufacturing. It is the use of flowing air to remove heat and moisture from tempered granulated material.
5.1 Cooling wind speed:
Controlling wind speed is the key to the cooling process. If the wind speed is too fast, the feed surface temperature drops fast; but the moisture and heat inside the feed cannot be completely released, the feed is easy to crack and break, and the powder content increases. If the wind speed is over slow, the moisture loss, and yield is low.
