Interaction between konjac glucomannan and tannic acid: Effect of molecular weight, pH and temperature

2019 ◽  
Vol 94 ◽  
pp. 451-458 ◽  
Author(s):  
Yun He ◽  
Shishuai Wang ◽  
Jing Li ◽  
Hongshan Liang ◽  
Xianlin Wei ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Tannic Acid ◽  
Konjac Glucomannan ◽  
Acid Effect

Studies on the Coordination Reaction of VO2+ and Tannic Acid in the Tannin Extract Desulfurization

2012 ◽  
Vol 239-240 ◽  
pp. 1573-1576
Author(s):  
Zhu Qing Gao ◽  
Xiao Dong Cai ◽  
Kai Cheng Ling
Keyword(s):  
Stability Constants ◽  
Tannic Acid ◽  
Ph Value ◽  
Protonation Constants ◽  
Conditional Stability ◽  
Tannin Extract ◽  
Acid Effect ◽  
Different Temperatures ◽  
The Stability ◽  
Apparent Stability

At different temperatures, the protonation constants of tannic acid and the complex apparent stability constants between tannic acid and VO2+ were determined by using pH potentimetric method. The results showed that the protonation constants and the complex apparent stability constants slightly decreased with the raising temperature. In accordance with the pH value in the tannin extract technology, the conditional stability constants of the complex were calculated on the basis of the acid effect of tannic acid and the hydrolysis effect of VO2+. It was found that pH greatly affected the stability constants of the complex , so pH must be strictly controlled in the tannin extract technology.

scholarly journals Galloylglucoses of low molecular weight as mordant in electron microscopy. I. Procedure, and evidence for mordanting effect.

1976 ◽  
Vol 70 (3) ◽  
pp. 608-621 ◽  
Author(s):  
N Simionescu ◽  
M Simionescu
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Tannic Acid ◽  
Sodium Borohydride ◽  
Low Molecular Weight ◽  
High Contrast ◽  
Experimental Conditions ◽  
Complex Effect ◽  
Tissue Contrast ◽  
Tissue Specimens

Gallotannin, consisting mainly of low molecular weight esters such as penta- and hexagalloylglucoses (commercially available as tannic acid produced from Turkish nutgall), can be used for increasing and diversifying tissue contrast in electron microscopy. When applied on tissue specimens previously fixed by conventional methods (aldehydes and OsO4), the low molecular weight galloylglucoses (LMGG) penetrate satisfactorily the cells and induce general high contrast with fine delineation of extra- and intracellular structures, especially membranes. In some features, additional details of their intimate configuration are revealed. Various experimental conditions tested indicate that the LMGG display a complex effect on fixed tissues: they act primarily as a mordant between osmium-treated structures and lead, and concomitantly stabilize some tissue components against extraction incurred during dehydration and subsequent processing. Experiments with aldehyde blocking reagents (sodium borohydride and glycine) suggested that the LMGG mordanting effect is not dependent on residual aldehydes groups in tissues.

Effect of Environmental Factors of Mannanase on Konjac Glucomannan Molecular Dimension

2011 ◽  
Vol 689 ◽  
pp. 308-314
Author(s):  
Xiao Yan Long ◽  
Xue Gang Luo ◽  
Ju Bai ◽  
Jia Feng Zhu
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Reaction Time ◽  
Environmental Factors ◽  
Weight Distribution ◽  
Degradation Process ◽  
Konjac Glucomannan ◽  
Molecular Dimension ◽  
Degradation Reaction ◽  
Theoretical Foundations

The environmental factors of mannanase konjac glucomannan (KGM) have been investigated in aqueous solution. Molecular weight (Mw) and molecular weight distribution (WMD) of the degraded KGM were measured by GPC. During the degradation process, the molecular weight of the enzymatic products decreases with reaction time, degradation reaction combining two reactions processed with different orders, while WMD broadens at first and then becomes narrow. The reduction of molecular dimension of KGM was lowered with temperature increase, but WMD increases. WMD was reduced with concentration of enzyme increase, but the reduction of molecular dimension of KGM was insignificant in the range of 2.0~6.5 u.mL-1of mannanase concentration. The results show that molecular dimension of KGM could be controlled by soft changes of reaction environment, dimension of KGM molecule could be decreased more than 100 times so as to obtain oligosaccharides, which offers the reference to reliable theoretical foundations and practical ground in exploiting KGM potential function and activity.

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