Synergistic construction of heat-stable resistant starch by confined Retrogradation of short-chain amylose within calcium alginate beads.

As a functional carbohydrate with dietary fiber-like properties, resistant starch (RS) has attracted attention for its potential to regulate blood glucose fluctuations. In this study, varying concentrations (10-40%) of short-chain amylose (SCA) were encapsulated within calcium alginate beads and subjected to retrogradation at 50 °C. The confined space within the beads facilitated molecular rearrangement and the formation of stable crystalline structures in the SCA. With increasing SCA concentration, the onset temperature (To) of the cooked beads increased up to 86.64 °C, and the enthalpy change (ΔH) gradually rose to 36.69 J·g-1, indicating enhanced thermal resistance. The RS content in the cooked beads increased significantly, reaching 51.3% at 40% SCA, far exceeding the 8.0% observed in non-encapsulated samples. The estimated glycemic index (eGI) decreased from approximately 103 to about 73, suggesting a significant reduction in digestibility. This strategy provides a feasible approach for designing heat-resistant RS-based ingredients for thermally processed foods.