Effect of Small and Large Wheat Starch Granules on Thermomechanical Behavior of Starch

TLDR: In this article, the physicochemical properties of small and large granule wheat starches were investigated to reveal whether gelatinization properties and rheological behavior differ between size classes of wheat starch.

Abstract: The physicochemical properties of small- and large-granule wheat starches were investigated to reveal whether gelatinization properties and rheological behavior differ between size classes of wheat starch. All samples contained 60% water (w/w, wb). The starch granule size and shape were examined by scanning electron microscopy in the separated A- and B-type granule populations and in the whole wheat starch granule population. Differential scanning calorimetry (DSC) and electron spin resonance (ESR) analyses were performed in parallel with rheological measurements using dynamic mechanical thermal analysis (DMTA) to relate the viscoelastic changes to modifications in dynamic properties of aqueous solutions and structural disorganization of starch. The small (B-type) granules had slightly higher gelatinization temperature and lower gelatinization enthalpy than did the large (A-type) granules. Also, B-type granules had higher enthalpy for the amylose-lipid complex transition. Moreover, our results su...