Topic
Glucomannan
About: Glucomannan is a research topic. Over the lifetime, 1254 publications have been published within this topic receiving 21993 citations.
Papers published on a yearly basis
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Papers
TL;DR: The structure of mannans and some biochemical properties and applications of mannan-degrading enzymes are reported, showing a complex system of sulfated structure.
Abstract: Hemicellulose is a complex group of heterogeneous polymers and represents one of the major sources of renewable organic matter. Mannan is one of the major constituent groups of hemicellulose in the wall of higher plants. It comprises linear or branched polymers derived from sugars such as d-mannose, d-galactose, and d-glucose. The principal component of softwood hemicellulose is glucomannan. Structural studies revealed that the galactosyl side chain hydrogen interacts to the mannan backbone intramolecularly and provides structural stability. Differences in the distribution of d-galactosyl units along the mannan structure are found in galactomannans from different sources. Acetyl groups were identified and distributed irregularly in glucomannan. Some of the mannosyl units of galactoglucomannan are partially substituted by O-acetyl groups. Some unusual structures are found in the mannan family from seaweed, showing a complex system of sulfated structure. Endohydrolases and exohydrolases are involved in the breakdown of the mannan backbone to oligosaccharides or fermentable sugars. The main-chain mannan-degrading enzymes include β-mannanase, β-glucosidase, and β-mannosidase. Additional enzymes such as acetyl mannan esterase and α-galactosidase are required to remove side-chain substituents that are attached at various points on mannan, creating more sites for subsequent enzymatic hydrolysis. Mannan-degrading enzymes have found applications in the pharmaceutical, food, feed, and pulp and paper industries. This review reports the structure of mannans and some biochemical properties and applications of mannan-degrading enzymes.
691 citations
TL;DR: In this article, the branching point of konjac glucomannan was determined by methylation analysis and 13C NMR spectroscopy, showing that β-C-1-linked C-6 carbon of glucosyl units were the branching units.
346 citations
TL;DR: Konjac glucomannan is a kind of neutral polysaccharides with excellent biocompatibility and biodegradable activities as mentioned in this paper and its derivatives in pharmaceutical, bio-technical, fine chemical fields etc.
339 citations
TL;DR: In this paper, X-ray diffractometry and FT-IR spectroscopy indicated that the addition of mannan induced a change in the crystal structure from the algal-bacterial type to the cotton-ramie type.
Abstract: Acetobacter xylinum was cultured in Hestrin-Schramm medium (control medium) and Hestrin-Schramm medium containing acetyl glucomannan (mannan medium). Loose bundles of the cellulose microfibrils are formed in the mannan medium in contrast to the normal ribbons being produced in the control medium. Rapid-freeze and substitution method followed by metal-shadowing revealed the droplet-like structures around the microfibril synthesized in the mannan medium. The cellulose synthesized in the mannan medium was stained heavily by the periodic acid-thiocarbohydrazide-silver proteinate (PATAg) method, while the cellulose synthesized in the control medium was not stained. X-ray diffractometry and FT-IR spectroscopy indicated that the addition of mannan induced a change in the crystal structure from the algal-bacterial type to the cotton-ramie type. Thus the presence of acetyl glucomannan in the medium prevents the assembly of cellulose microfibrils and changes the crystal structure of cellulose.
304 citations
TL;DR: Results suggest that G lowered liver cholesterol by a viscosity-mediated interference of cholesterol absorption, in contrast to CH, which appears to lower cholesterol through a different mechanism.
Abstract: Glucomannan, a viscous polysaccharide, and chitosan, a derivative of chitin, have both been demonstrated to lower cholesterol in animals. However, the mechanism of cholesterol lowering has not been established for either material. This study was conducted to determine the effect of glucomannan (G), chitosan (CH), or an equal mixture of the two (G + CH) on cholesterol absorption and fat and bile acid excretion. Rats were fed a modified AIN-93G diet for 18 d containing 0.125 g/100 g cholesterol and initially 10 g/100 g of the test materials or cellulose (C) as the control. However, the concentration of test materials and cellulose was reduced to 7.5 g/100 g after 1 wk due to lower weight gain compared with controls. Total liver cholesterol was significantly reduced in G, CH and G + CH groups compared with the C group. The intestinal contents supernatant viscosity of the C and the CH groups was negligible, whereas both G and G + CH produced high viscosities. Cholesterol absorption, measured by the fecal isotope ratio method, was significantly reduced from 37.5% in the C group to 20.2% in G, 18.2% in G + CH and 9.4% in CH. Daily fecal fat excretion did not differ between the C and G groups, but was significantly greater in G + CH and CH compared with the C and G groups. Daily fecal bile acid excretion was significantly greater in the CH and G + CH groups compared with the C and G groups. These results suggest that G lowered liver cholesterol by a viscosity-mediated interference of cholesterol absorption. In contrast, CH appears to lower cholesterol through a different mechanism.
287 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2025 | 82 |
| 2024 | 151 |
| 2023 | 67 |
| 2022 | 108 |
| 2021 | 28 |
| 2020 | 39 |