食品挤压膨胀及其对质构特性影响的数学模型

Mathematical Models of Food Extrusion Expansion and Its Effect on Texture

挤压是一项有效的食品加工技术,正确建立挤压食品特性变化的数学模型是对产品质量进行预测和控制的基础。对于挤压膨化加工,熔融体在排离模口后发生膨胀,所得产品的结构决定其质构。对描述气泡成核、气泡生长、模口膨胀3个过程的数学模型做了综述;对气泡生长模型作了重点介绍,以气泡周围熔融体的受力平衡为基础,阐述了各模型的来历,并将其分为单气泡生长模型和气室模型两大类。还论述了挤压条件与产品结构、产品结构与产品质构的数学关系。最后对今后的研究方向做了展望。

Extrusion is an effective food processing technology.For predicting and controlling the quality of extrudate,it is necessary to establish mathematical models,which can properly describe the property changes induced by extrusion.While extruding food,melt swells after flowing out the die,and the resulted structure controls the texture of final products.The mathematical models for three processes,bubble nucleation,bubble growth,and swell after the die are reviewed in this paper.Bubble growth models are emphasized.Based on the momentum equilibrium of the melt around a bubble,the development of various models of bubble growth is elucidated.All the models are divided into two groups,single bubble models and cell models.The relation of extrusion conditions with extrudate structure and the relation of the structure with the texture are stated.Finally,future researches needed are suggested.