挤压加工参数对重组米生产过程及产品膨胀度的影响

为了考察重组米生产过程中挤压加工变量对几种系统参数与产品膨胀度的影响，试验以杂交籼米（9?718品种）为原料，利用响应面模型，以螺杆转速、进料速度、进料含水率以及末端机筒温度为输入变量，以挤压系统参数（物料温度、模头压强、扭矩、比机械能和产品含水率）和重组米膨胀度为响应变量，探索在重组米生产过程中加工变量与系统参数及产品膨胀度的关系。结果表明，压强、比机械能和产品膨胀度都受到4个挤压变量的显著影响，但是物料温度受进料速度影响不显著，马达扭矩受末端机筒温度影响不显著，产品含水率仅受进料含水率的显著影响。比机械能与螺杆转速正相关，与进料速度、进料含水率和末端机筒温度负相关。所得二次回归模型均拟合良好，建立的挤压数学模型可应用于重组米生产，为重组米工业化生产的过程预测和产品性质预测提供参考。

Effect of extrusion parameters on production process and expansion ratio of reformed rice

Response surface methodology (RSM) was used to study the effects of screw speed, feed rate, feed moisture content, and terminal barrel temperature on several system parameters (product temperature, die pressure, motor torque, specific mechanical energy and product moisture content) and physical properties (expansion ratio) of the reformed rice made by hybrid indica rice (type 9718). Second-order polynomials were used to model the extruder responses as a function of process variables. Die pressure, specific mechanical energy and expansion ratio were affected by all four process variables, while product moisture content was only influenced by feed moisture content. Product temperature was affected by all variables except for feed rate, and motor torque was affected by all variables except for terminal barrel temperature. Specific mechanical energy increased with screw speed increment, while feed moisture and terminal barrel temperature reduced with feed rate increment. The high correlation between the models and the measured data showed that the calculated second-order polynomials were sufficiently accurate and valuable tools in interpreting the multi-variable field of extrusion cooking of reformed rice.