Morphological, Ultrastructural and Rheological Evaluation of Soy and Cottonseed Flours Texturized by Extrusion and Nonextrusion Processing

Texturized protein products were produced from defatted soy and glandless cottonseed flours by extrusion and nonextrusion processes. Scanning electron microscope photomicrographs showed that the surface morphology of both types of texturized products were similar and it was concluded that both processes were successfully used to create texture in the raw materials. However, rheological data indicated that the nonextrusion process produced a product which had significantly higher Ln stress and resilience values. The difference in Ln stress and resilience between the extrusion texturized products and their non‐extrusion counterparts is due to the differences in the ultrastructural arrangement of protein and insoluble carbohydrate components of the respective products. Based on the above, it is postulated that the working and kneading of the extrusion screw is not a prerequisite for the formation of texture.