Yang Miao, Zhang Xun, Wu Min, Zhang Tianqi, Zou Fanglei, Yang Shuqi
College of Engineering, China Agricultural University, Beijing 100083, China.
Foods. 2025 Sep 8;14(17):3137. doi: 10.3390/foods14173137.
This study developed an optimized cooling die configuration to improve the fibrous structure and texture of protein extrudates. Six designs, combining three cross-sectional shapes and two flow channel layouts, were evaluated through numerical simulations based on the physical properties of pea protein isolate (PPI) and extrusion parameters. The results show that PPI exhibits pronounced shear-thinning behavior, with viscosity decreasing by more than 85% as the temperature increases from 35 °C to 135 °C. Among all designs, the rectangular outlet with a serpentine cooling channel performed best, showing a center-to-wall temperature difference of 12.4 °C compared with 7.8 °C for the circular die, a 35% higher heat transfer coefficient, a wall-to-center viscosity ratio of 7.4 compared with 4.9 for the square die and 3.7 for the circular die, and a maximum wall shear rate of 3.42 s compared with 2.15 s for the circular die. The rectangular outlet increases the center-to-wall temperature gradient, while the serpentine channel extends the flow path to raise shear and velocity gradients, together promoting fiber alignment and improving the structure of plant-based meat. These findings provide a theoretical foundation for cooling die optimization and offer a practical approach to control fiber formation in plant-based meat.
本研究开发了一种优化的冷却模头结构，以改善蛋白质挤出物的纤维结构和质地。基于豌豆分离蛋白（PPI）的物理性质和挤出参数，通过数值模拟对结合三种横截面形状和两种流道布局的六种设计进行了评估。结果表明，PPI表现出明显的剪切变稀行为，当温度从35℃升高到135℃时，粘度降低超过85%。在所有设计中，带有蜿蜒冷却通道的矩形出口表现最佳，其中心到壁的温差为12.4℃，而圆形模头为7.8℃，传热系数高35%，壁到中心的粘度比为7.4，方形模头为4.9，圆形模头为3.7，最大壁面剪切速率为3.42 s，圆形模头为2.15 s。矩形出口增加了中心到壁的温度梯度，而蜿蜒通道延长了流动路径，以提高剪切和速度梯度，共同促进纤维排列并改善植物基肉类的结构。这些发现为冷却模头优化提供了理论基础，并为控制植物基肉类中的纤维形成提供了一种实用方法。
