Structural and Functional Properties of Underutilised Cowpea and Moth Bean Starches

Starches isolated as by-products from protein extraction of three cowpea and three moth bean cultivars were investigated for their structural and functional properties, including particle size, apparent amylose content (AAC), crystallinity, gelatinisation and retrogradation behaviour, pasting properties, and gel texture. Cowpea starches exhibited higher AAC, gelatinisation temperatures, retrogradation enthalpy, and gel strength, indicating greater thermal stability and stronger gel network formation. In contrast, moth bean starches showed lower ACC, higher relative crystallinity, and greater gelatinisation enthalpy, reflecting more compact native crystalline structures, due to a higher amylopectin content. The lower AAC of moth beans resulted in limited retrogradation and softer gels. To evaluate the multivariate relationships among the starch samples, cluster analysis was performed, which grouped the samples according to botanical origin. This classification underscored the distinct structural and functional attributes differentiating cowpea and moth bean starches. These findings provide insight into cultivar-dependent starch behaviour. Cowpea starches may be suited for applications requiring thermal stability and a firm texture, such as noodle formulations and microwave foods, while moth bean starches offer potential for products with smooth textures and low retrogradation, such as in instant or ready-to-eat food products.