Effects of yellow mealworm replacing fish meal on the quality of low starch slow-sinking extruded feed

The purpose of this experiment was to study the effects of different processing parameters and replacement ratio of yellow mealworm protein replacing fish meal on the quality of low starch slow-sinking aquatic extruded feed, and to optimize the optimal operating parameters. In this study, a Box-Behnken experimental design was used to optimize parameters of the three independent variables with the replacement ratio of yellow mealworm protein, the moisture content of mash feed after conditioning and the die temperature, and the variation ranges were from 0 to 50%, 26% to 30%, 100 to 140 ℃, respectively. The bulk density, sinking speed, the sinking ratio at 10 min and energy consumption of extruded pellet feed were used as the dependent variables to optimize the three independent variables. The results showed that the bulk density of low starch slow-sinking extruded feed gradually increased with the increase of the replacement ratio of yellow mealworm protein, increased with the increase of moisture content, and increased slightly with the increase of die temperature. The sinking speed gradually increased with the increase of the replacement ratio of yellow mealworm protein, and increased first and then decreased with the increase of the die temperature. When the replacement ratio of yellow mealworm protein was 0 ~ 25%, the sinking speed gradually increased with the increase of moisture content. When the replacement ratio of yellow mealworm protein was 50%, the sinking speed increased first and then decreased. The sinking ratio at 10 min gradually increased with the increase of replacement ratio of yellow mealworm protein, and increased with the increase of moisture content. The sinking ratio at 10 min increased first and then decreased with the increase of die temperature. The energy consumption gradually increased with the increase of the replacement ratio of yellow mealworm protein, decreased with the increase of moisture content after conditioning, and gradually decreased with the increase of die temperature. The results of variance analysis showed that the order of effect of each factor on the quality of low starch slow-sinking aquatic extruded pellet feed was as follows: replacement ratio of yellow mealworm protein, moisture content and die temperature. The optimal process parameters and the optimal replacement ratio for processing low starch slow-sinking aquatic extruded pellet feed were optimized: the moisture content after the conditioning was 27.6%, the die temperature was 108 °C, and the replacement ratio was 15.0%. Under this process parameters, the sinking speed was 7.72 cm/s, the sinking ratio at 10 min was 95%, and the energy consumption was 34.39 (kW·h)/t. The relative error of verification test results was less than 4%, the model optimization results were reliable, and the research results can provide a reference for the production of low starch slow-sinking aquatic extruded feed.