Exploring Characteristics of High‐Temperature Dry‐Heated Waxy Wheat Starch

ABSTRACT The objective of this work was to explore the properties of waxy wheat starch after dry‐heating it with sodium phosphate at 150°C and 160°C for 2 h. Phosphate groups were bonded to the starch molecule, as evidenced by the Fourier‐transform infrared spectra showing strengthened vibrations of P─O─C and P═O bonds at 836 cm − 1 and 889 cm − 1 and the region of 1,150 cm − 1 – 1,300 cm − 1 , respectively. Scanning electron microscopy (SEM) and X‐ray diffraction (XRD) results revealed that dry‐heating had no effect on the A‐type starch polymorph and the granule morphological characteristics, except for pore formation on the surface of starch granules dry‐heated at 160°C. Differential scanning calorimetry (DSC) result showed that gelatinization temperatures were reduced in starches dry‐heated at both 150°C and 160°C for 2 h. Starch dry‐heated at 160°C for 2 h exhibited increasing viscosity with pasting time, indicating high shear resistance. These results suggested that dry‐heating waxy wheat starch with sodium phosphate at 160°C for 2 h resulted in cross‐linking and then led to the absence of peak and breakdown viscosity and high shear resistance. This study offers a new approach for modifying starch to enhance functional property, contributing new insights to starch technology.