Characterisation of Fractions Obtained by Isoamylolysis and Ion-exchange Chromatography of Cationic Waxy Maize Starch

Abstract

Isoamylase hydrolysates of wet-(WC) and dry-cationised (DC) waxy maize starch were fractionated by ion-exchange chromatography on CM-Sepharose into an unbound and four bound fractions. The amount of bound dextrins was higher in the WC than in the DC sample. The fractions were characterised by gel-permeation chromatography and proton-NMR spectroscopy. The unbound fraction from the WC sample consisted mainly of linear chains formed from amylopectin. The dextrins in the bound fractions contained increased amounts, from 1.2-7.9, of cationic substituents per molecule and the degree of polymerisation increased with the density of substituents. Dextrins weakly bound to CM-Sepharose had a linear structure, whereas more tightly bound fractions were mixtures of linear and branched dextrins. In the latter, the debranching was incomplete because of sterical hindrance by substituents at or close to the branch points. Most of the dextrins were partly hydrolysed by β-amylase, but the more highly substituted fractions possessed also a population of β-amylase resistant dextrins, suggesting substituents at the non-reducing ends.

Characterization of Dextrins obtained by Enzymatic Treatment of Cationic Potato Starch

“…1). These trends were as expected because the amounts of cationic groups close to the branches increase with an elevated DS resulting in the formation of branched, isoamylase-resistant fragments [20,22]. One would expect a similar trend for the pullulanase.…”

“…Enzymatic analysis methods have previously been used for the study of hydroxypropylated manioc [12] and potato starches [13,14], methylated potato starch [9,15,16,17], oxidized [18,19] and cationic potato starch [20], and cationic waxy maize starch [21,22]. Earlier studies of cationic starches indicate that the amorphous parts are readily substituted [23,24] and the placements of the cationic groups within the starch granules vary depending on the chosen cationization method [20][21][22]. The event of substitution of the amylose has also been under investigation but the course of the substitution is still somewhat unclear.…”

Hydrolysis of Maltoheptaose in Flow through Silicon Wafer Microreactors Containing Immobilised α‐Amylase and Glycoamylase

“…5. In succinate buffer and in CaCl 2 solution the hydrolysis of maltoheptaose to glucose was found to be 68 and 67 mol% AGU, while in NH 4 OAc it was 61%. In contrast, hydrolysis with both enzymes in batch using succinate buffer showed 80% turnover of the substrate to Experiments were performed at 1 mL/ min at room temperature with a maltoheptaose concentration of 0.12 mM AGU at pH 5.1.…”

“…Structural information about the polymer becomes accessible by interpreting the formation of enzyme-specific hydrolysis products. In recent years a-amylase, b-amylase, pullulanase and glycoamylase (AMG or amyloglucosidase) have been used to draw conclusions about the properties of the starch chain, the starch granule and for derivatised starch [2][3][4][5][6][7].…”

Synthesis and characterization of synthetic polymer colloids colloidally stabilized by cationized starch oligomers

“…49 When the glucose unit is substituted with hydroxypropyl-trimethyl-ammonium, the anomeric 1 H signal comes out at 5.58 ppm and the CH 3 signal of the substituent at 3.21 ppm. 50,51 Their respective signal areas are denoted as I (1!4)-a , I ared , I bred , I (1!6)-a , I sub , and I CH 3 . The number-average degree of polymerization of the debranched oligomers, X n , is then obtained from: 50…”