Abstract
This study aimed to elucidate the critical role of swollen starch granules state in starch gel formation, focusing on identifying the underlying physicochemical and molecular mechanisms. Swollen starch granules with varying integrity were generated through controlled shear treatment (3000 rpm, 0.5–10 min), and their gelation behavior and associated mechanisms were thoroughly evaluated. Dynamic shear rheology monitored the gelation process at 4 °C for 18 h. Texture analysis showed a significant decline in gel strength with increasing shear duration, corresponding to the progressive loss of swollen granule integrity. X-ray diffraction and differential scanning calorimetry demonstrated that after 10 min of shear-induced granule disruption, the relative crystallinity of the gel decreased from 20.01% to 7.82%, accompanied by a reduction in retrogradation enthalpy from 6.75 to 2.86 J/g. Small-angle X-ray scattering showed a decrease in the ordered aggregate size within retrograded gels, from 23.590 to 18.899 nm, as swollen granule fragmentation intensified. These findings highlight the role of intact swollen starch granules in stabilizing gel networks through their space-filling effects. Composed primarily of amylopectin, these granules are embedded within a continuous amylose matrix, creating a concentrated molecular environment that promotes amylopectin recrystallization. Furthermore, the ordered double-helix clusters formed by amylose rearrangement help connect neighboring swollen granules, thereby promoting the formation of a more cohesive and interconnected gel network. This study provides insights into the role of starch granule integrity on starch-based gels and shows that precise control of granule integrity could improve textural attributes.
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•Controlled shear regulates swollen granule integrity to explore starch gel formation.•Intact swollen granules stabilized gel by spatial filling and molecular interactions.•Starch pastes with intact swollen granules formed rigid gels after 18 h at 4°C.•Crystallinity drop (20.0%→7.8%) aligned with swollen granule fragmentation increase.
