Skip to main content
All news
Press Review Animal Feed

The importance of conditioning

Along with grinding, conditioning is one of the most important factors in achieving good physical quality.
SHARE THIS

Along with grinding, conditioning is one of the most important factors in achieving good physical quality.
Once the ingredients are mixed and transferred to the bin, the feed flows into a feeder which moves the feed at the desired rate into the conditioning chamber. This is where steam and molasses are added, according to the level specified by the feed formula. 


In the adjacent chart you can see the effect of conditioning temperature and time on pellet durability (Svihus 2005).

The increase of conditioning time will raise the penetration of  moisture and heat into the particles.

The use of high temperature conditioning may improve the efficiency of thermo-mechanical processing, pellet quality and uniformity and broiler performance when ambient temperatures and ingredient moisture levels are compliant. In addition, it reduces the level of harmful bacteria and energy requirement and guarantees a longer service life of die and rolls. 

In fact, increasing the conditioning temperature will decrease the temperature rise through the die during the pelleting process, which is due to frictional heat between the die and pellet surface. In addition, gelatinization of starches produced during the conditioning acts as a lubricant in the die hole.
 

Conditioning is accomplished by the addition of controlled amounts of steam, that supplies moisture for lubrication, liberates natural oils and results in partial gelatinization of starches.
Starch gelatinization is a process of breaking down the inter molecular bonds of starch molecules in the presence of water and heat, allowing the hydrogen bonding sites (the hydroxyl hydrogen and oxygen) to engage more water. This irreversibly dissolves the starch granule in water. Water acts as a plasticizer. 


Cooked, unmodified starch, when cooled for a long enough period, will thicken (or gel) and rearrange itself again to a more crystalline structure. This process is called retrogradation.
During the cooling process, starch molecules gradually aggregate to form a gel and molecular associations occur: Amylose-Amylose ; Amylose-Amylopectin; Amylopectin-Amylopectin.
 

The moisture in the feed that is being processed in the conditioner serves as the conduit for the transfer of the heat into the feed particles. Studies have shown that moisture addition to the meal has a positive effect on the conditioning process, as you can see in the following chart:



The effect of moisture and temperature on level of gelatinization


Summarizing, the four basic reasons for conditioning are:

1. To lubricate for faster production rate.

2. To lubricate to extend die life.

3. To lubricate to reduce energy costs.

4. To gelatinize starch for nutritional value.