Pasting properties and multi-scale structures of Spirodela starch and its comparison with normal corn and rice starch

Turion is a starch source that can overcome the limitations of land and season. The starch obtained from turion had a positive impact on the development of the starch industry. In this study, a novel starch was extracted from Spirodela polyrhiza turion. The structure and the relationship between structure and gelatinization properties of Spirodela starch were studied by comparison with that of normal corn starch and rice starch and principal component analysis. The amylose contents, short-range order, hydrogen bond, chain-length distributions, the degree of polymerization, crystalline and semi-crystalline structure, and granule structure of Spirodela starches were investigated. The results showed that Spirodela starch has a medium amylose content (27.48 g/100 g), and has a lower hydrogen bond strength, double helix number, crystallinity (18.41 g/100 g), looser semi-crystalline layer, and a higher specific surface area of the holes on the surface of the granules than the other two starches. The structure of Spirodela starch is obviously looser than that of normal corn starch and rice starch. The loose structure of Spirodela starch causes the lowest gelatinization temperature (66.9 °C) and the highest peak viscosity (2664.50 m Pa·s) among the three starch. Elucidating the structure and pasting properties of Spirodela starch will help understand its application in industrial processing. • Starch with 98.85% purity was extracted from Spirodela polyrhiza turion. • Four levels of structure of Spirodela starch were analyzed. • The structural basis of starch gelatinization was speculated. • Spirodela starch has a looser structure than corn starch and rice starch.