Gel growth of aqueous konjac glucomannan solution containing sodium trimetaphosphate dialyzed with dilute sodium hydroxide

Kazuto Yoshiba; Ikumi Ujiie; Takao Yamamoto; Toshiaki Dobashi

doi:10.1016/j.carbpol.2020.117329

Gel growth of aqueous konjac glucomannan solution containing sodium trimetaphosphate dialyzed with dilute sodium hydroxide

Carbohydr Polym. 2021 Mar 1:255:117329. doi: 10.1016/j.carbpol.2020.117329. Epub 2020 Nov 4.

Authors

Kazuto Yoshiba¹, Ikumi Ujiie², Takao Yamamoto³, Toshiaki Dobashi²

Affiliations

¹ Division of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan. Electronic address: yoshiba@gunma-u.ac.jp.
² Division of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
³ Division of Pure and Applied Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.

PMID: 33436172
DOI: 10.1016/j.carbpol.2020.117329

Abstract

The growth rate of the hydrogel of the aqueous konjac glucomannan (KGM) solution containing sodium trimetaphosphate (STMP) dialyzed with aqueous NaOH was investigated in a rectangular cell. The growth rate of the KGM-STMP gel depended on both the KGM and STMP concentrations in addition to the NaOH concentration. The initial growth rate of the KGM-STMP gel was closely related to the diffusion of NaOH into the KGM-STMP solution, leading to the ring-opening reaction of STMP and the deacetylation of KGM at the interface. The time course of the gelation of the KGM-STMP solution was analyzed on the basis of the moving boundary picture theory by introducing the characteristic length to express the consumption of NaOH in the gel layer accompanying the decomposition of STMP. Dynamic mechanical measurements were performed to compare the gelation of the KGM-STMP solution mixed homogeneously with dilute NaOH and the gel dynamics by the dialysis method.

Keywords: Diffusion; Gelation; Hydrogel; Konjac glucomannan; One-dimensional growth; Sodium trimetaphosphate.