Abstract：
The ability to modulate direct expanded product structures improves the versatility and range of product applications. The effect of nucleating agents, namely, talc and calcium carbonate (CC), on the expansion characteristics of pea starch extrudates as impacted by screw speed was explored. Pea starch blends with increasing levels of nucleating agents (0.25%, 1%, and 2%) at 18% moisture (w.b.) were extruded across a range of screw speeds (150, 250, 350, and 450 rpm). The water absorption index, water solubility index (WSI), expansion ratio (ER), unit density, and cell count were determined to evaluate the performance of nucleating agents. The nucleating efficiency of CC, as assessed by cell count, improved with increasing screw speeds. In contrast, the nucleating efficiency of talc was influenced by inclusion levels irrespective of screw speed. ER values ranged from 2.10 to 2.88, where higher nucleating agent inclusions and screw speeds corresponded with lower ER values. Increased nucleating agents and screw speeds corresponded to higher WSI values suggesting the nucleating agents promoted starch degradation. The nucleating agents appeared to promote flow instabilities indicated upon assessment of the extrudate surface. PRACTICAL APPLICATION: This study provides helpful information on the expanded extrudate structure of pea starch as influenced by screw speed and nucleating agents. These findings may help the food industry select processing parameters and appropriate nucleating agent inclusion levels when producing new expanded products with unique textures.
摘要：
调节直接扩展产品结构的能力提高了产品应用的多功能性和范围。成核剂的作用，即,滑石和碳酸钙（CC），研究了螺杆转速对豌豆淀粉挤出物膨胀特性的影响。成核剂含量增加的豌豆淀粉混合物(0.25%，1%,和2%)在18%水分(w.b.)下在一系列螺杆速度(150、250、350和450rpm)下挤出。吸水指数，水溶性指数（WSI），膨胀比（ER），单位密度，和细胞计数被测定以评价成核剂的性能。CC的成核效率，通过细胞计数评估，提高螺杆速度。相比之下,滑石的成核效率受夹杂物含量的影响，而与螺杆转速无关。ER值范围为2.10至2.88,其中较高的成核剂夹杂物和螺杆速度对应于较低的ER值。增加的成核剂和螺杆速度对应于更高的WSI值,表明成核剂促进淀粉降解。成核剂似乎促进了在评估挤出物表面时指示的流动不稳定性。实际应用：这项研究提供了有关豌豆淀粉的膨胀挤出物结构的有用信息，受螺杆速度和成核剂的影响。这些发现可能有助于食品工业在生产具有独特质地的新膨胀产品时选择加工参数和适当的成核剂含量。
