December 11, 2008
Extra water in mixer produces better pellet quality
Scientists from Norway's FelleskjÃ¸pet FÃ´rutvikling and Norwegian University of Life Sciences and the Kansas State University have added extra water to the mixer prior to steam conditioning to study the effects on pellet quality of pig feeds.
Two diets for finishing pigs were used to determine the effect of adding water into the mixer on processing characteristics and pellet quality.
The researchers used a barley-based diet and a corn-based diet. Both diets were produced without and with use of an expander.
The corn-based diet was processed with motor load held constant to maximize feed mill output, and production rate held constant to minimize energy use.
At a constant motor load and a constant production rate, adding up to 30 grams water/ per kilogram into the corn-based diet prior to steam conditioning increased pelleting efficiency by 22 percent and 9 percent, pellet durability index (PDI) was improved from 84 percent to 89 percent and from 79 percent to 87 percent, respectively.
Expander conditioning of the corn-based diet increased PDI from 92 percent at none to 94 percent at 30 g/kg water addition.
Correspondingly, modified PDI was increased from 89 percent to 93 percent at adding 30 grams water/ per kilogram into the mixer prior to expander conditioning.
Improvements were shown in pellet efficiency, PDI and modified PDI by 15 percent, 10 percent and 10 percent, respectively for barley-based diet pellets with the addition of 120 grams water/ per kilogram into the mixer.
The overall conclusion from the experiment was that adding water into the mixer before steam conditioning improved pelleting efficiency and pellet quality in barley- and corn-based diet for finishing pigs.