Insights into the multiscale structure and thermal characteristics of chestnut starch

This study compared the multiscale structure of ten chestnut starches in cultivars of different origins and further investigated the correlation between amylose content, amylopectin chain length distribution (CLD), Fourier transform-infrared (FTIR) characteristics, Raman spectra, X-ray diffraction (XRD) patterns and thermal properties. The amylose content ranged from 20.9 % to 29.5 %. Amylopectin chain length showed a bimodal distribution, and the proportion of A, B1, B2 and B3 chains was 25.8–28.2 %, 42.6–45.1 %, 18.2–25.3 % and 6.4–10.3 %, respectively. Most samples exhibited a C-type crystal structure, while the relative crystallinity ranged from 56.9 % to 62.3 %. Significant differences were observed in structural parameters of short-range molecular order and double helical structure of infrared spectra, full width of half-maximum at 480 cm−1 and relative area (480/865 cm−1) of Raman spectra. Amylose content was positively correlated with gelatinization temperature. Reduced amylose content and presence of long chains of amylopectin enhanced crystallization. However, no correlation was found between amylopectin CLD and thermal properties. The results provide useful information for understanding the structure-property correlation of starch.