One of the most important quality parameters of aquafeed is the water stability. It means after a certain
time immersion in water, the composition of aquafeed will not be dissolved or lost.
Generally,it is measured through the ratio between the lost weight in unit time and initial feed weight. It
isrequired that the lost percentage of aquafeed should be less than 20% immersion in water for 30mins.
If the aqua feed has poor water stability, it will be dissolved, swelling and dispersed easily, which reduces
the utilization rate of aquafeed and seriously affects the economic benefit of aquaculture.
Therefore, water stability is an important indicator to measure the aquafeed quality. Four main factors affect
the quality of aquafeed.
Crushing Granularity
The fineness of crushing has a tremendous influence on water stability of fish feed pellet.The oversize fine
ness decreases corresponding superficial area, which leads to the starch on the surface can not be gelatiniz
ed totally when conditioning and it affects the cohesive action. The feed pellet is dispersed easily when soak
ing.
Adhesiveness
Binder is the additive that used in aquafeed making. It is also the key material to determine the water stabi
lity of aquafeed. During the process of feed pellet production, adding appropriate additive is helpful to increase
the water stability of aquafeed. In addition to the nature, adhesive strength of binder also relates to feed pellet
types and processing method.
Ring die compression ratio
Ring die compression ratio is the ratio between the length and diameter of die holes, which also influences water
stability of fish feed pellet. If the feed pellet mill has the ring die with larger ratio, the feed pellets produced by it
will have the feature of better hardness, closer structure and longer water resistant time. The normal ring die com
pression ratio is 14-17, while for shrimp feed pellet, the ratio is 17-20.
If you intend to make feed pellets for the aquatic animals, it is better to take the above influencing factors into con
sideration. I hope you can benefit from it.
Conditioning
The key to shape feed pellet lies in the conditioning. The steam with high temperature and pressure acts on the feed
pellet, which makes the starch gelatinized, protein denatured and increases the cohesiveness and plasticity of feed pe
llet. Besides, it ensures the close structure, appropriate hardness and good water stability.
To achieve the conditioning effectiveness, mastering the tempering time and temperature, selecting the saturated vapor,
keeping stable constant pressure are necessary.