A Comparative Study of A‐ and B‐Type Starch Granules in Normal and Waxy Wheat Starch: Properties, Retrogradation, and Digestion

Wheat starch exhibits a characteristic particle size distribution that directly influences its structural and functional properties. This study investigated how A‐ and B‐type granules from normal (NS) and waxy (WS) wheat differ in physicochemical properties and retrogradation behavior. SEM images showed that WS had a rough and porous surface than NS, but the small starch granules showed ellipsoid shapes with more incomplete particles and irregular edges than the large starches. The waxy B‐type starch (WS‐B) had the highest contents of lipid, protein, and damaged starch than other starches, facilitating the maximum gelatinization enthalpy and lowest setback viscosity, indicating the best thermal stability. Meanwhile, the normal A‐type starch (NS‐A) showed a less crystalline structure, which swelled less at high temperature with the lowest peak and breakdown viscosity. In vitro digestion results confirmed that the amorphous regions in NS‐A were hydrolyzed slowly with a lower k value (0.0016). After 7 days of storage time at 4°C, the leached amylose content and retrogradation enthalpy of WS‐B increased significantly to 84.86% and 3.51 J/g, respectively. The findings revealed that A‐ and B‐type starches were responsible for different retrogradation periods, which will be available for promoting the shelf‐life of wheat‐based products.