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Guar gum

About: Guar gum is a research topic. Over the lifetime, 5611 publications have been published within this topic receiving 105940 citations.


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Journal ArticleDOI
TL;DR: The enzyme showed higher activity on LBG and konjac glucomannan than on guar gum galactomannan and could hydrolyze mannooligosaccharides larger than mannobiose, while it did not exhibit any activities towards carboxymethylcellulose and para-nitrophenyl-β-mannopyranoside.
Abstract: A mannanase was purified from a cell-free extract of the recombinant Escherichia coli carrying a Bacillus subtilis WL-3 mannanase gene. The molecular mass of the purified mannanase was 38 kDa as estimated by SDS-PAGE. Optimal conditions for the purified enzyme occurred at pH 6.0 and 60°C. The specific activity of the purified mannanase was 5,900 U/mg on locust bean gum (LBG) galactomannan at pH 6.0 and 50°C. The activity of the enzyme was slightly inhibited by Mg2+, Ca2+, EDTA and SDS, and noticeably enhanced by Fe2+. When the enzyme was incubated at 4°C for one day in the presence of 3 mM Fe2+, no residual activity of the mannanase was observed. The enzyme showed higher activity on LBG and konjac glucomannan than on guar gum galactomannan. Furthermore, it could hydrolyze xylans such as arabinoxylan, birchwood xylan and oat spelt xylan, while it did not exhibit any activities towards carboxymethylcellulose and para-nitrophenyl-β-mannopyranoside. The predominant products resulting from the mannanase hydrolysis were mannose, mannobiose and mannotriose for LBG or mannooligosaccharides including mannotriose, mannotetraose, mannopentaose and mannohexaose. The enzyme could hydrolyze mannooligosaccharides larger than mannobiose.

35 citations

Journal ArticleDOI
TL;DR: It is concluded that guar is fermented in the human colon, producing rises in breath methane and serum acetate but not hydrogen, and psyllium had no effect on hydrogen, methane, or acetate, this does not prove that it is not fermented.

35 citations

Journal ArticleDOI
TL;DR: In this article, a mixture of deacetylated xanthan and locust-bean gum showed the highest dynamic modulus, about twice that of the mixture of native Xanthan.

35 citations

Journal ArticleDOI
TL;DR: An oscillating capillary rheometer was used to investigate the effects of xanthan deacetylation on the viscoelastic properties and intrinsic viscosity ofxanthan and guar mixtures in dilute aqueous solutions, demonstrating that intermolecular binding occurred between the disordered segments of xAnthan and Guar gum in dilutes aqueously solutions.
Abstract: ABSITRACT: An oscillating capillary rheometer was used to investigate the effects of xanthan deacetylation on the -3 viscoelastic properties and intrinsic viscosity of xanthan and guar niktures in dilute aqueous solutions. Deacetylated xanthan exhibited a stronger synergistic interaction with guar than native zanthan did due to the destabilized helical structure and increased chaln flexibility of the deacetylated zanthan. No gels were obsersed for all xanthan-guar mixtures. Native xanthan-guar mixtures exhibited a llqnid-like behavior whereas deacetylated xanthanar mixtures exhibfted a gel-like behavior. The relative viscosity and elasticity of deacetylated xanthan-guar mixtures were much stronger than those for native lanthan-guar mixtures. The intrinsic viscosities of deacetylated ianthan-guar mixtures were higher than the calculated values assuming no interaction, whereas the intrinsic viscosities of native zanthan-guar mixtures were lower than the calculated values assuming no interaction, demonstrating that inter-molecular binding occurred between the disordered segments of xanthan and guar gum in dilute aqueous solutions.

35 citations

Journal ArticleDOI
TL;DR: In this article, the influence of chemical composition and structure of guar gum derivatives on water retention capacity (WR) and rheological behavior of fresh state cement-based mortars was examined.

35 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023188
2022416
2021211
2020231
2019262
2018298