Physicochemical properties of a new starch from turion of Spirodela polyrhiza.

Starch from the turion of Spirodela polyrhiza ZH0196 is a new resource with great development values. The solubility, swelling power, thermogravimetric analysis (TGA), enzyme susceptibility, and in vitro digestibility of Spirodela starch, paste clarity, settling volume, and the rheology property of Spirodela starch paste, strength, elasticity, and freeze-thaw stability of Spirodela starch gel were studied. The properties of Spirodela starch were compared with those of normal corn starch and rice starch. The possible relationship between properties and structure of three kinds of starch was analyzed by principal component analysis (PCA). The results showed that the rapidly digested starch, slowly digested starch and resistant starch were 86.63 %, 4.43 %, and 8.94 % respectively. Spirodela starch has higher strength (17.77 g), elasticity (4.98 g/s) of starch paste, and freeze-thaw stability of starch gel than those of normal corn starch and rice starch. The rheological results showed that the stickiness maintainability of starch paste was normal corn > Spirodela > rice and Spirodela starch paste had compact paste structures with the tan δ between 0.33 and 0.38. This study has significant value in the application of Spirodela starch.