Cold-water solubility, oil-adsorption and enzymolysis properties of amorphous granular starches

Amorphous granular starches from six different botanical sources were obtained by heating starch suspensions in water at or near pasting temperature. Their morphology was divided into two types: one was ghost-like with openings on the surface (sweet potato, tapioca, wheat and maize starches), and the other was gel-like with the surface porous structures (mung bean and pea starches). Their mean particle sizes (D50), specific surface areas, amylose contents, and molecular gyration z-average radii (Rz) were 30.6–57.0 μm, 0.359–0.649 m2/g, 13.7%–16.8%, and 88.9–115.3 nm, respectively. The amorphous granular starches showed better cold-water solubility (78.5%–94.2%), oil-adsorption capacity (43.1%–62.1%) and enzymolysis rate (58.5%–82.6%) characteristics at room temperature than those of the granular cold-water soluble (GCWS) starches and the pre-gelatinized (PG) starches. They could be used as thickening agents, adhesives, carriers of liposoluble function factors and basic materials of throat lozenges.