Identification of lotus seeds stored over different periods by analyzing the changes in the chemical structure of starch

• The wavenumber shift of lotus seed starch from 1019.6 cm −1 to 1016.3 cm −1 happens during storage. • The resonance of C4 in lotus seed starch shifts to higher fields during storage. • Intensities of diffraction angle at 2 θ 11.40 o /17.96 o of lotus seed starch increases/decreases during storage. • The single helical conformations of lotus seed starch transform into double ones. • The crystallinity of lotus seed starch increases during storage.