Polyphenol-mediated structural reorganization of A-, B-, and C-type starches into V-type complexes with modulated digestibility

Interactions between polyphenols and starch are critical for modulating starch functionality through structural reorganization. This study systematically compared the interaction of young apple polyphenols (YAP) with A-type (corn starch, CS), B-type (potato starch, POS), and C-type (pea starch, PES) under autoclaving. Multi-technique analysis confirmed the formation of starch-YAP complexes and structural reorganization into A+V- and B+V-type crystalline polymorphs. Distinct differences in complex properties were observed among the crystal types. CS-based complexes (CSY_4) demonstrated the highest loading capacity (785.61 ± 0.37 mg/g) and long-range crystallinity (9.35%), yet exhibited the lowest short-range order (0.885 ± 0.044); PES-based complexes (PESY_4) showed the highest encapsulation efficiency (97.40 ± 0.02%) alongside the lowest swelling power (1.63 ± 0.01 g/g) and solubility (0.36 ± 0.01 g/g); whereas POS-based complexes (POSY_4) presented the lowest amylose content (13.71 ± 0.17%). These structural modifications led to markedly suppressed digestibility, with resistant starch content increasing to 52.02 ± 2.41% (CSY_4), 56.55 ± 0.43% (POSY_4), and 57.19 ± 1.80% (PESY_4), and POS demonstrated the greatest efficacy in lowering the estimated glycemic index (eGI) (ΔeGI = 14.83). The study elucidates a crystal-type-dependent strategy for designing slow-digesting starch-based functional foods through polyphenol-mediated structural engineering.