Multi-scale structural changes in lintnerized starches from three coloured potatoes

Abstract

Three kinds of potato starch were treated with 2.2 N HCl at 35 °C for 40 days, and their susceptibility to acid hydrolysis and the resulting structural changes were evaluated. Red potato starch was more susceptible to acid hydrolysis and presented highest rate of hydrolysis. Lintnerized starches had relatively low average molecular weights and z-average radius of gyration. HPAEC analyses showed three lintners presented different molecular size distributions. Lintnerized yellow potato starch had few chains of DP ≤ 12 (2.58 mol%) and more chains of DP ≥ 37 (8.16 mol%). Furthermore, the similarities of the branch-chain length distributions before and after debranching indicated the lintners consisted primarily of linear molecules. After lintnerization, most starch granules were degraded, and the birefringence disappeared from some granules. X-ray diffraction patterns revealed that the relative crystallinity significantly increased after lintnerization. DSC analyses showed that lintners displayed broader thermal-transitions.

Keywords: Acetic acid (PubChem CID: 176); Crystal properties; Dimethyl sulfoxide (PubChem CID: 679); Hydrochloric acid (PubChem CID: 313); Lintnerization; Molecular size distribution; Morphological characteristics; Phenol (PubChem CID: 996); Potato starch; Sodium acetate (PubChem CID: 517045); Sodium cyanoborohydride (PubChem CID: 20587905); Sulfuric acid (PubChem CID: 1118).