The Structural and Physicochemical Properties of Isolated Starches from Canna (Canna edulis Ker.) Cultivated from Different Regions of China

Canna (Canna edulis Ker.) starch is an important non-conventional starch in global applications. In this study, the structural and physicochemical properties of canna starches extracted from four different geographical regions in China were investigated. The four starches (CES-DH, CES-MS, CES-YB, and CES-YX) exhibited relatively high total starch contents (82.51–93.22%). Apparent and true amylose contents varied markedly among samples, ranging from 31.44% to 43.62% and from 15.21% to 35.90%, respectively. Morphologically, the granules were oval and disc-shaped, with D50 values of 20.19–48.35 μm. CES-YX showed a distinct C-type pattern, while other starches exhibited B-type crystallinity, and relatively crystallinity values among samples were between 20.53% and 25.36%. IR absorbance ratios R1047/1022 and R995/1022 varied from 0.56 to 0.63 and from 1.15 to 1.26, respectively. Gelatinization temperatures and enthalpy revealed distinct thermal behaviors among the starches, corresponding to substantial differences in pasting properties with wide ranges in peak, breakdown, and setback viscosities. All starch pastes exhibited shear-thinning behaviors and weak gel characteristics. Notably, CES-YB demonstrated high potential as an effective food thickener and stabilizer, as distinguished by the high final viscosity and consistency coefficient (K), whereas the high amylose and resistant starch content in CES-YX made it a promising ingredient for low-glycemic-index food formulations. These findings provided a theoretical basis and practical guidance for the targeted utilization of canna starch in the food industry.