Starch-Dominated, Matrix-Modulated Gelation and Structural Recovery in Air-Classified Protein-Rich and Starch-Rich Chickpea Fractions

Abstract Air classification of milled pulse flours yields protein-rich fine and starch-rich coarse fractions, yet both are composite matrices where starch, protein, and fiber govern functionality. Desi (DCP) and kabuli (KCP) chickpeas were jet-milled at two rotor speeds, air-classified, and characterized for composition, pasting, gelatinization, starch structure, and rheology. Milling severity altered starch partitioning in a variety-dependent manner: higher rotor speed reduced starch in DCP fines (21 → 17%) but increased it in KCP fines (8 → 12%). Coarse fractions concentrated starch to >50% and showed the highest viscosities and moduli. Structural recovery after large-amplitude deformation increased with starch content and decreased with protein and fiber, consistent with starch playing the dominant role in network formation while protein and fiber disrupt connectivity as discrete inclusions. The composition–recovery relationship was stronger in KCP fines (R2 = 0.87–0.93 vs 0.16–0.36 for DCP), consistent with near-percolation-threshold behavior. Co-optimization of protein enrichment, starch partitioning, and matrix architecture is required for functional dry-fractionated pulse ingredients.