Study on the physicochemical properties of purple sweet potato starch

With starch extracted from purple sweet potato slag as raw material, this paper studied the chemical component, particle surface structure, crystal structure, gel texture, thermodynamic properties and rheological properties of the starch, comparing with the potato starch, corn starch and sweet potato starch at the same time. The main results and findings were summarized as follows: the starch content and amylose content of purple sweet potato starch were 98.78% and 19.74% respectively (dry weight); average particle size of the purple sweet potato starch granules was 17 μm, so the starch can be classified as medium size starch granule, and crystal form of type C; the starch gel showed a high springiness and chewiness, low hardness(3.095 × 102 g) and moderate viscosity (24.72 g · s); the gelatinization temperature scope was from 61.5°C to 78.0°C, and the peak temperature was 72.6°C; the purple sweet potato slag starch paste was non-Newtonian fluid with yield stress.