Substitution of wheat semolina with intact chickpea cells: A study on extruded pasta quality.

Abstract

Intact cells, e.g. isolated from chickpea (intact chickpea cells, ICC) is getting attention as a new functional ingredient for lowering the glycaemic response. ICC applied to various foods, e.g. bread, biscuits and noodles, that do not require high shear, have shown improved nutritional functionality. However, the retention of cell intactness at high shear operation, e.g. extrusion, is not known. Thus, the manuscripts investigate the application of ICC in pasta replacing the wheat semolina (30 %) at three extrusion screw speeds of 200, 400 and 600 rpm. The control pasta was made from either 100 % semolina or 30 % semolina with chickpea flour (CF), where almost all intact cellular structure is broken. Based on the confocal laser microscopic observation, ICC retained cellular integrity at extrusion speeds from 200 to 600 rpm, leading to reduction in starch digestibility of pasta (55.28-64.46 %) compared to semolina (75.14-84.09 %) and CF-blended pasta (64.53-74.65 %). CF and ICC substituted pasta had higher protein and dietary fibre content, but lower starch content compared to semolina-based pasta. The physiochemical analysis including X-ray diffraction (XRD), thermal properties and pasting properties for the starch structure in pasta samples showed that the shear force leads to the disruption of starch structure during the extrusion process and is dependent upon the screw speed. Cooking properties demonstrated reduced optimum cooking times and increased cooking loss with chickpea substitutions, influenced by different chemical compositions and weaker gluten networks. Overall, substituting semolina with CF and ICC alters pasta's nutritional profile and cooking behaviour, highlighting potential applications in functional food development.