Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Ave., St. Paul, MN 55108, USA.
Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave SE #250, Minneapolis, MN 55455, USA.
Food Res Int. 2023 Jan;163:112250. doi: 10.1016/j.foodres.2022.112250. Epub 2022 Nov 30.
Twin-screw micro compounding is introduced as a novel technique to process and characterize small plant protein samples under conditions that are relevant for meat analogue processing. Small samples of pea protein isolate (PPI) (5 cm, corresponding to ∼7 g of hydrated sample) are batch-processed at water contents between 40 and 70 % w/w and temperatures between 90 and 120 °C. Screw speed (100-400 rpm) and residence time (1-9 min) are varied resulting in values of the specific mechanical energy (SME) between ∼20 and 2000 kJ/kg, which is the range relevant for plant protein extrusion. Micro compounding process data provides information on several aspects of the rheological behavior of PPI. Shear thinning behavior is observed for PPI. The viscosity of the PPI during micro compounding was found to exponentially decrease with water content. The temperature dependence is consistent with an Arrhenius-type model. The extruded strands (length: ∼15 cm; diameter: 3.0 ± 0.2 mm) are characterized by scanning electron microscopy (SEM), differential solubility, water holding capacity (WHC), and texture profile analysis (TPA). The hardness as determined from TPA increases linearly with screw speed and residence time, jumps to higher values above the denaturation temperature of the PPI and decreases exponentially with the water content during processing. Micro compounding is found to be a useful technique to convert small plant protein samples at water contents between about 40 and 60 % w/w into texturized matrices and investigate the rheological behavior of plant protein isolates under conditions that are relevant for extrusion processing.
双螺杆微细化共混被引入作为一种新颖的技术，用于在与肉类模拟物加工相关的条件下处理和表征小植物蛋白样品。豌豆蛋白分离物（PPI）的小样品（5 cm，对应于约 7 g 水合样品）在水含量为 40-70%w/w 和温度为 90-120°C 之间进行分批处理。螺杆速度（100-400 rpm）和停留时间（1-9 min）变化，导致特定机械能量（SME）的值在 20-2000 kJ/kg 之间，这是植物蛋白挤压的相关范围。微细化共混过程数据提供了关于 PPI 流变行为的几个方面的信息。观察到 PPI 的剪切稀化行为。发现 PPI 在微细化共混过程中的粘度随水含量呈指数下降。温度依赖性与 Arrhenius 型模型一致。挤出的条（长度：约 15 cm；直径：3.0±0.2 mm）通过扫描电子显微镜（SEM）、差示溶解度、持水能力（WHC）和质地剖面分析（TPA）进行表征。通过 TPA 确定的硬度与螺杆速度和停留时间呈线性增加，在 PPI 的变性温度以上跳跃到更高的值，并随加工过程中的含水量呈指数下降。发现微细化共混是一种有用的技术，可将水含量在约 40-60%w/w 之间的小植物蛋白样品转化为纹理化基质，并研究与挤压加工相关的植物蛋白分离物的流变行为。
