Researchers in Iran recently completed a study investigating the effects of pre-gelatinized (PG) taro and broken rice and extruder die temperatures on the physical properties of extruded pellets. Their findings indicate that PG taro and broken rice can be used to produce high quality floating pellets.
According to the study abstract, published in the Journal of Animal Feed Science and Technology, the research consisted of two experiments. The first experiment was conducted to evaluate the effects of PG taro and extruder die head temperature, and a subsequent experiment was conducted using PG broken rice. All the blends were preconditioned to a 40% moisture content and then extruded using a single screw extruder.
The findings showed in both experiments that PG taro and broken rice inclusion levels and die temperature had significant effects on most of the physical properties of the pellets, except for pellet durability index.
Changing the inclusion rate of PG taro and broken rice from 15 to 25% significantly increased the expansion ratio and floatability of the extruded pellets. Similarly, as the die temperature was elevated in both experiments, the floatability of the extruded pellets in the diet containing PG taro and broken rice increased by 114.62% and 21.88%, respectively. It was also noted that use of PG taro and broken rice resulted in highly durable pellets in all treatments.
Further, microstructure analysis of the extruded pellets revealed that using PG taro and broken rice, the surface of the extruded pellets became coarser when the die temperature was elevated from 125 to 170 °C and the PG taro and broken rice inclusion level was at 15%.
The research team concluded that pre-gelatinized taro and broken rice could be used to manufacture higher quality floating pellets.
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