20
Towards quantitative engineering for aquafeed extrusion process operation Hongyuan Cheng, Min Xue, Junguo Li, Chinese Academy of Agriculture Sciences, Tor A. Samuelsen, Nofima, Mette Sørensen, Nord University
Viable aquatic feed in extrusion production The quality of extruded pellets is determined by the diet formulation and the extrusion processing parameters. The diet is formulated to meet the nutritional requirement of the aquatic species, while extrusion processing parameters can be adjusted to control buoyancy, sinking velocity, hardness, durability, water solubility and oil absorption capacity, as shown in Figure 1. The physical properties of the pellet are affected by the viscous behavior of the diet formulation in the extruder barrel. New feed formulations are usually tested and optimized in lab or pilot scale extruder systems and then upscaled to industrial production where different extruder systems are used. Although the extrusion technology has been applied for decades, the extrusion is still a “black box” and depends on specific skills to operate the extruder. Often, the optimization process is costly and time-consuming. A quantitative engineering method for the feed extrusion process operation is warranted. Quantitative engineering method for pellet quality control Physicochemical changes and rheological ingredient properties are important factors that define the final physical pellet quality. In fish feed extrusion, pellet expansion and immediate shrinkage can be visually observed when the pellets are discharged from the extruder die holes and is controlled by the die melt viscosity and the viscoelastic behavior of the extrudate. Therefore, we assume that extruded
Figure 1. Feed pellet quality is determined by the feed formulation and the extrusion parameters
Figure 2. Quantitative calculation for every pellet quality parameter.
pellet quality parameters can be described by empirical rheological equations. In this work, a rheological equation-based model has been developed to predict physical quality
Aquafeed: Advances in Processing & Formulation Vol 12 Issue 4 2020
