Effect of Degree of Acetylation on Gelation of Konjac Glucomannan

Abstract

Effect of the degree of acetylation (DA) on the gelation behaviors on addition of sodium carbonate for native and acetylated konjac glucomannan (KGM) samples with a DA range from 1.38 to 10.1 wt % synthesized using acetic anhydride in the presence of pyridine as catalyst was studied by dynamic viscoelastic measurements. At a fixed alkaline concentration (CNa), both the critical gelation times (tcr) and the plateau values of storage moduli (G'sat) of the KGM gels increased with increasing DA, while at a fixed ratio of alkaline concentrations to values of DA (CNa/DA), similar tcr and values independent of DA were observed. On the whole, increasing KGM concentration or temperature shortened the gelation time and enhanced the elastic modulus for KGM gel. The effect of deacetylation rate related to the CNa/DA on the gelation kinetics of the KGM samples was discussed.

A novel global hydrodynamic analysis of the molecular flexibility of the dietary fibre polysaccharide konjac glucomannan

“…It is composed of a backbone chain of β-1,4 linked D-mannose and D-glucose with a low degree of acetyl groups related to its gel formation properties (Maeda, Shimahara & Sugiyama, 1980;Nishinari, Williams & Phillips, 1992;Takigami, 2000;Williams, Foster, Martin, Norton, Yoshimura & Nishinari, 2000;Katsuraya, Okuyama, Hatanaka, Oshima, Sato & Matsuzaki, 2003;Gao & Nishinari, 2004).…”

Electrolyte effect on gelation behavior of oppositely charged nanocrystalline cellulose and polyelectrolyte

“…Generally, the n value was relevant to the physically fractal dimension, and reflected the degree of compactness of the network, and the lower values of n implied a more highly elastic gel (Gao & Nishinari, 2004;Nordby, Kjøniksen, Nyström, & Roots, 2003;Kjøniksen, Hiorth, Roots, & Nysrtom, 2003). The larger tan ı and n values at higher c NaCl in Table 1 suggested a less elastic, as a result of the screening.…”

Gel Glukomanan Porang-Xantan dan Kestabilannya Setelah Penyimpanan Dingin dan Beku

“…Pada kondisi netral, GK dapat bersinergi membentuk gel paling kuat dengan xantan dibandingkan dengan hidrokoloid lain, seperti guar gum, karagenan, sodium alginat, sodium karboksil selulosa, metil selulosa, hidroksi etil selulosa, dan gum arabik (Liang dkk., 2011). Mekanisme pembentukan gel pada glukomanan konjac sangat dipengaruhi oleh berat molekul (Shen dkk., 2009) dan derajat asetilasi (Gao dan Nishinari, 2004;Nishinari dan Takahashi, 2003), konsentrasi, suhu dan konsentrasi alkali (Alonso-Sande dkk., 2009;Herranz dkk., 2013). Penelitian sinergisme glukomanan porang, hasil isolasi langsung dari porang segar yang dikompositkan dengan xantan dalam pembentukan gel dan kestabilannya selama penyimpanan belum dilakukan.…”