Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
Institute of Informatics, Hacettepe University, Ankara, Turkey.
Food Res Int. 2021 Feb;140:109996. doi: 10.1016/j.foodres.2020.109996. Epub 2020 Dec 15.
Red lentils have a great potential to be used as healthy ingredients in puffed snacks due to their excellent nutritional qualities. However, these types of ingredients with relatively higher protein and fiber content when compared to ingredients that are typically used for the manufacture of puffed foods (e.g., refined cereal flours/starches) result in inferior textural quality. Extrusion processing parameters such as screw speed, moisture content and injection pressure of a blowing agent can be manipulated to optimize the microstructure of an extrudate, and as a consequence the texture of the final puffed product. In this study, X-Ray microtomography imaging is used to characterize and quantify the detailed microstructure of red lentil extrudates. The results indicate that an increase in the injected pressure of the physical blowing agent could be correlated with a decrease in mean cell size and wall thickness, as well as an increase in the number of cells. Evidence of wall rupture with an increased screw speed is also visible, and that effect can be counterbalanced by a higher moisture content during processing. A large variation of the cell wall thickness inside an extrudate (which can induce a weaker cellular structure) as well as a larger cell size and higher amount of wall rupture, significantly reduce the hardness of extrudates. This novel effort to quantitatively characterize the microstructure of red lentil extrudates using X-Ray microtomography establishes that an optimal product texture could, in principle, be achieved by manipulating extrusion parameters to achieve the perfect snack texture.
红扁豆由于其优良的营养价值，具有作为膨化小吃中健康成分的巨大潜力。然而，与通常用于膨化食品制造的成分（例如精制谷物面粉/淀粉）相比，这些蛋白质和纤维含量相对较高的成分会导致较差的质地。可以操纵挤压加工参数，例如螺杆速度、水分含量和膨化剂的注入压力，以优化挤出物的微观结构，从而优化最终膨化产品的质地。在这项研究中，使用 X 射线微断层扫描成像来表征和量化红扁豆挤出物的详细微观结构。结果表明，物理膨化剂注入压力的增加可以与平均细胞尺寸和壁厚的减小以及细胞数量的增加相关联。随着螺杆速度的增加，还可以看到壁破裂的证据，并且可以通过在加工过程中提高水分含量来平衡该效果。挤出物内部细胞壁厚度的较大变化（这可能会导致较弱的细胞结构）以及较大的细胞尺寸和更高的壁破裂程度，会显著降低挤出物的硬度。使用 X 射线微断层扫描对红扁豆挤出物的微观结构进行定量表征的这项新努力表明，通过操纵挤压参数来实现理想的小吃质地，可以在原则上实现优化的产品质地。
