The growing demand for sustainable protein alternatives has increased interest in legume-derived proteins. Dry and wet fractionation are widely used to obtain protein-rich fractions from legumes, but they also generate substantial co-products that are underutilised. The valorisation of these co-products is essential for enhancing resource efficiency and sustainability in legume fractionation. Five dehulled legumes (Desi chickpea, Kabuli chickpea, mung bean, faba bean and lupin) were subjected to dry fractionation (air classification) and wet fractionation (isoelectric point precipitation). Their co-products, coarse fractions (dry), and non-solubilised fractions (wet), were characterised for yield, composition, particle size distribution, pasting behaviour, and other functional properties (water- and oil-holding capacity, swelling power, water solubility index, foaming properties and emulsifying properties). Dry-fractionated coarse fractions exhibited comparable functionalities to dehulled flours (0.7–1.5×), while wet-isolated non-solubilised fractions were distinctly different from flours, displaying higher pasting viscosity (~2×), water holding capacity (1.5–3.5×) and oil holding capacity (1.5-5×), but lower foaming capacity (~0.1×) and emulsifying activity (<0.1×). These differences are proposed to be due to the superior ability of alkali-based wet fractionation to dissociate starch/protein/fibre aggregates compared with milling and air classification. The results suggest that dry-fractionated co-products may be considered as flour substitutes in food applications, while wet-fractionated starch/fibre-rich co-products provide food ingredient functionalities related to water and oil structuring both before and after cooking without emulsification or foaming. • Co-products from both dry air classification and wet alkaline fractionation of five dehulled legumes were isolated and characterised. • Wet fractionation co-products have greater purity, water/oil holding capacity and pasting viscosity than dry fractionation. • Dry fractionation co-products have greater emulsifying and foaming properties than wet fractionation. • Functional properties correlate with protein (emulsification/ foaming), starch (swelling power) or fibre (water/oil-holding capacity) contents.
Liu et al. (Wed,) studied this question.