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Feng Peng - One of the best experts on this subject based on the ideXlab platform.

  • effect of structural characteristics of corncob hemicelluloses fractionated by graded Ethanol Precipitation on furfural production
    Carbohydrate Polymers, 2016
    Co-Authors: Huiling Li, Longfei Jian, Feng Peng
    Abstract:

    In the present study, a graded Ethanol Precipitation technique was employed to obtain hemicelluloses from the alkali-extracted corncob liquid. The relationship between the structural characteristics of alkali-soluble corncob hemicelluloses and the production of furfural was investigated by a heterogeneous process in a biphasic system. Results showed that alkali-soluble corncob hemicelluloses mainly consisted of glucuronoarabinoxylans and l-arabino-(4-O-methylglucurono)-d-xylans, and the drying way had less influence on the sugar composition, molecular weights and the functional groups of hemicelluloses obtained by the different Ethanol concentration Precipitation except for the thermal property, the amorphous structure and the ability for the furfural production. Furthermore, alkali-soluble corncob hemicelluloses with higher xylose content, lower branch degree, higher polydispersity and crystallinity contributed to the furfural production. A highest furfural yield of 45.41% with the xylose conversion efficiency of 99.06% and the furfural selectivity of 45.84% was obtained from the oven-dried hemicelluloses precipitated at the 30% (v/v) Ethanol concentration.

  • studies on the starch and hemicelluloses fractionated by graded Ethanol Precipitation from bamboo phyllostachys bambusoides f shouzhu yi
    Journal of Agricultural and Food Chemistry, 2011
    Co-Authors: Pai Peng, Jing Bian, Feng Peng, Feng Xu
    Abstract:

    Starch from bamboo Phyllostachys bambusoides f. shouzhu Yi evaluated by means of solid-state 13C CP/MAS NMR and X-ray diffraction showed a typical B-type pattern with a very low degree of crystallinity (10.9%). In addition to starch, alkali-soluble hemicelluloses were further fractionated by graded Precipitation at Ethanol concentrations of 0 (HA), 15, 30, 45, 60, and 75% (v/v). Chemical composition and structural features of the six hemicellulosic subfractions were investigated by a combination of sugar analysis, GPC, FT-IR, GC-MS, 1D (1H and 13C) and 2D (HSQC) NMR spectra, and thermal analysis. The results showed that the bamboo hemicelluloses were O-acetylated 4-O-methyl-glucuronoarabinoxylans (GAX) consisting of a linear (1→4)-β-d-xylopyranosyl backbone decorated with branches at O-3 of α-l-arabinofuranosyl (5−12 mol %) or at O-2 of 4-O-methylglucuronic acid units and acetyl groups (0.8−11 mol %). The molecular weights of these polysaccharides ranged between 13400 and 67500 g/mol, and the molar ratios...

  • isolation and fractionation of hemicelluloses by graded Ethanol Precipitation from caragana korshinskii
    Carbohydrate Research, 2010
    Co-Authors: Jing Bian, Pai Peng, Feng Peng, Feng Xu
    Abstract:

    Abstract Caragana korshinskii hemicelluloses were isolated with 10% KOH at 25 °C for 10 h from the delignified materials. The alkali-extractable hemicelluloses were then successively sub-fractionated by graded Precipitation at final Ethanol concentrations of 10%, 20%, 30%, 45%, 60%, and 80%, respectively. Neutral sugars and molecular weight analyses of the six hemicellulosic subfractions revealed that the molecular weights and the distribution of branches along the xylan backbone are different among the hemicellulosic fractions obtained in various Ethanol concentrations. The less branched hemicelluloses with large molecules were precipitated in lower Ethanol percentages, while with the increasing Ethanol concentrations, more branched hemicelluloses with low molecular weights were obtained. 1 H and 13 C NMR studies revealed that the hemicellulosic subfraction precipitated at an Ethanol concentration of 45% had a backbone of d -xylose residues and were branched mainly through 4- O -methyl-α- d -glucopyranosyl units.

  • fractional study of alkali soluble hemicelluloses obtained by graded Ethanol Precipitation from sugar cane bagasse
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Feng Peng, Jing Bian, Feng Xu, Pai Peng
    Abstract:

    The two hemicellulosic fractions were subsequentially extracted with 5% and 8% NaOH aqueous solution at a solid to liquid ratio of 1:25 (g mL−1) at 50 °C for 3 h from the water, 1 and 3% NaOH-treated sugar cane bagasse, and subfractionated into six preparations by a graded Ethanol Precipitation method at concentrations of 15%, 30% and 60% (v/v). Sugar composition and molecular weight analysis showed that, with an increasing concentration of Ethanol, hemicellulosic subfractions with both higher Ara/Xyl ratios and higher molecular weights were obtained. In other words, with an increasing Ethanol concentration from 15% to 60%, the Ara/Xyl ratios increased from 0.043 in H1 to 0.088 in H3 and from 0.040 in H4 to 0.088 in H6, and the weight-average molecular weights of hemicellulosic subfractions increased from 42 430 (H1) to 85 510 (H3) g mol−1 and from 46 130 (H4) to 64 070 (H6) g mol−1, respectively. The results obtained by the analysis of Fourier transform infrared, sugar composition, and 1H and 13C nuclear...

  • fractional study of alkali soluble hemicelluloses obtained by graded Ethanol Precipitation from sugar cane bagasse
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Feng Peng, Jing Bian, Pai Peng, Junli Ren, Runcang Sun
    Abstract:

    The two hemicellulosic fractions were subsequentially extracted with 5% and 8% NaOH aqueous solution at a solid to liquid ratio of 1:25 (g mL(-1)) at 50 degrees C for 3 h from the water, 1 and 3% NaOH-treated sugar cane bagasse, and subfractionated into six preparations by a graded Ethanol Precipitation method at concentrations of 15%, 30% and 60% (v/v). Sugar composition and molecular weight analysis showed that, with an increasing concentration of Ethanol, hemicellulosic subfractions with both higher Ara/Xyl ratios and higher molecular weights were obtained. In other words, with an increasing Ethanol concentration from 15% to 60%, the Ara/Xyl ratios increased from 0.043 in H(1) to 0.088 in H(3) and from 0.040 in H(4) to 0.088 in H(6), and the weight-average molecular weights of hemicellulosic subfractions increased from 42 430 (H(1)) to 85 510 (H(3)) g mol(-1) and from 46 130 (H(4)) to 64 070 (H(6)) g mol(-1), respectively. The results obtained by the analysis of Fourier transform infrared, sugar composition, and (1)H and (13)C nuclear magnetic spectroscopy showed that the alkali-soluble hemicelluloses had a backbone of xylose residues with a beta-(1-->4)-linkage and were branched mainly through arabinofuranosyl units at C-2 and/or C-3 of the main chain, whereas the differences may occur in the distribution of branches along the xylan backbone.

Pai Peng - One of the best experts on this subject based on the ideXlab platform.

  • studies on the starch and hemicelluloses fractionated by graded Ethanol Precipitation from bamboo phyllostachys bambusoides f shouzhu yi
    Journal of Agricultural and Food Chemistry, 2011
    Co-Authors: Pai Peng, Jing Bian, Feng Peng, Feng Xu
    Abstract:

    Starch from bamboo Phyllostachys bambusoides f. shouzhu Yi evaluated by means of solid-state 13C CP/MAS NMR and X-ray diffraction showed a typical B-type pattern with a very low degree of crystallinity (10.9%). In addition to starch, alkali-soluble hemicelluloses were further fractionated by graded Precipitation at Ethanol concentrations of 0 (HA), 15, 30, 45, 60, and 75% (v/v). Chemical composition and structural features of the six hemicellulosic subfractions were investigated by a combination of sugar analysis, GPC, FT-IR, GC-MS, 1D (1H and 13C) and 2D (HSQC) NMR spectra, and thermal analysis. The results showed that the bamboo hemicelluloses were O-acetylated 4-O-methyl-glucuronoarabinoxylans (GAX) consisting of a linear (1→4)-β-d-xylopyranosyl backbone decorated with branches at O-3 of α-l-arabinofuranosyl (5−12 mol %) or at O-2 of 4-O-methylglucuronic acid units and acetyl groups (0.8−11 mol %). The molecular weights of these polysaccharides ranged between 13400 and 67500 g/mol, and the molar ratios...

  • isolation and fractionation of hemicelluloses by graded Ethanol Precipitation from caragana korshinskii
    Carbohydrate Research, 2010
    Co-Authors: Jing Bian, Pai Peng, Feng Peng, Feng Xu
    Abstract:

    Abstract Caragana korshinskii hemicelluloses were isolated with 10% KOH at 25 °C for 10 h from the delignified materials. The alkali-extractable hemicelluloses were then successively sub-fractionated by graded Precipitation at final Ethanol concentrations of 10%, 20%, 30%, 45%, 60%, and 80%, respectively. Neutral sugars and molecular weight analyses of the six hemicellulosic subfractions revealed that the molecular weights and the distribution of branches along the xylan backbone are different among the hemicellulosic fractions obtained in various Ethanol concentrations. The less branched hemicelluloses with large molecules were precipitated in lower Ethanol percentages, while with the increasing Ethanol concentrations, more branched hemicelluloses with low molecular weights were obtained. 1 H and 13 C NMR studies revealed that the hemicellulosic subfraction precipitated at an Ethanol concentration of 45% had a backbone of d -xylose residues and were branched mainly through 4- O -methyl-α- d -glucopyranosyl units.

  • fractional study of alkali soluble hemicelluloses obtained by graded Ethanol Precipitation from sugar cane bagasse
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Feng Peng, Jing Bian, Feng Xu, Pai Peng
    Abstract:

    The two hemicellulosic fractions were subsequentially extracted with 5% and 8% NaOH aqueous solution at a solid to liquid ratio of 1:25 (g mL−1) at 50 °C for 3 h from the water, 1 and 3% NaOH-treated sugar cane bagasse, and subfractionated into six preparations by a graded Ethanol Precipitation method at concentrations of 15%, 30% and 60% (v/v). Sugar composition and molecular weight analysis showed that, with an increasing concentration of Ethanol, hemicellulosic subfractions with both higher Ara/Xyl ratios and higher molecular weights were obtained. In other words, with an increasing Ethanol concentration from 15% to 60%, the Ara/Xyl ratios increased from 0.043 in H1 to 0.088 in H3 and from 0.040 in H4 to 0.088 in H6, and the weight-average molecular weights of hemicellulosic subfractions increased from 42 430 (H1) to 85 510 (H3) g mol−1 and from 46 130 (H4) to 64 070 (H6) g mol−1, respectively. The results obtained by the analysis of Fourier transform infrared, sugar composition, and 1H and 13C nuclear...

  • fractional study of alkali soluble hemicelluloses obtained by graded Ethanol Precipitation from sugar cane bagasse
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Feng Peng, Jing Bian, Pai Peng, Junli Ren, Runcang Sun
    Abstract:

    The two hemicellulosic fractions were subsequentially extracted with 5% and 8% NaOH aqueous solution at a solid to liquid ratio of 1:25 (g mL(-1)) at 50 degrees C for 3 h from the water, 1 and 3% NaOH-treated sugar cane bagasse, and subfractionated into six preparations by a graded Ethanol Precipitation method at concentrations of 15%, 30% and 60% (v/v). Sugar composition and molecular weight analysis showed that, with an increasing concentration of Ethanol, hemicellulosic subfractions with both higher Ara/Xyl ratios and higher molecular weights were obtained. In other words, with an increasing Ethanol concentration from 15% to 60%, the Ara/Xyl ratios increased from 0.043 in H(1) to 0.088 in H(3) and from 0.040 in H(4) to 0.088 in H(6), and the weight-average molecular weights of hemicellulosic subfractions increased from 42 430 (H(1)) to 85 510 (H(3)) g mol(-1) and from 46 130 (H(4)) to 64 070 (H(6)) g mol(-1), respectively. The results obtained by the analysis of Fourier transform infrared, sugar composition, and (1)H and (13)C nuclear magnetic spectroscopy showed that the alkali-soluble hemicelluloses had a backbone of xylose residues with a beta-(1-->4)-linkage and were branched mainly through arabinofuranosyl units at C-2 and/or C-3 of the main chain, whereas the differences may occur in the distribution of branches along the xylan backbone.

  • comparative study of hemicelluloses obtained by graded Ethanol Precipitation from sugarcane bagasse
    Journal of Agricultural and Food Chemistry, 2009
    Co-Authors: Feng Peng, Jing Bian, Feng Xu, Pai Peng
    Abstract:

    The sequential treatment of dewaxed sugarcane bagasse with H2O and 1 and 3% NaOH at a solid to liquid ratio of 1:25 (g mL−1) at 50 °C for 3 h yielded 74.9% of the original hemicelluloses. Each of the hemicellulosic fractions was successively subfractionated by graded Precipitation at Ethanol concentrations of 15, 30, and 60% (v/v). Chemical composition, physicochemical properties, and structures of eight precipitated hemicellulosic fractions were elucidated by a combination of sugar analysis, nitrobenzene oxidation of bound lignin, molecular determination, Fourier transform infrared (FT-IR), 1H and 13C nuclear magnetic spectroscopies, and thermal analysis. The results showed that the sequential treatments and graded Precipitations were very effective on the fractionation of hemicelluloses from bagasse. Comparison of these hemicelluloses indicated that the smaller sized and more branched hemicelluloses were extracted by the hot water treatment; they are rich in glucose, probably originating from α-glucan a...

Runcang Sun - One of the best experts on this subject based on the ideXlab platform.

  • fractional study of alkali soluble hemicelluloses obtained by graded Ethanol Precipitation from sugar cane bagasse
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Feng Peng, Jing Bian, Pai Peng, Junli Ren, Runcang Sun
    Abstract:

    The two hemicellulosic fractions were subsequentially extracted with 5% and 8% NaOH aqueous solution at a solid to liquid ratio of 1:25 (g mL(-1)) at 50 degrees C for 3 h from the water, 1 and 3% NaOH-treated sugar cane bagasse, and subfractionated into six preparations by a graded Ethanol Precipitation method at concentrations of 15%, 30% and 60% (v/v). Sugar composition and molecular weight analysis showed that, with an increasing concentration of Ethanol, hemicellulosic subfractions with both higher Ara/Xyl ratios and higher molecular weights were obtained. In other words, with an increasing Ethanol concentration from 15% to 60%, the Ara/Xyl ratios increased from 0.043 in H(1) to 0.088 in H(3) and from 0.040 in H(4) to 0.088 in H(6), and the weight-average molecular weights of hemicellulosic subfractions increased from 42 430 (H(1)) to 85 510 (H(3)) g mol(-1) and from 46 130 (H(4)) to 64 070 (H(6)) g mol(-1), respectively. The results obtained by the analysis of Fourier transform infrared, sugar composition, and (1)H and (13)C nuclear magnetic spectroscopy showed that the alkali-soluble hemicelluloses had a backbone of xylose residues with a beta-(1-->4)-linkage and were branched mainly through arabinofuranosyl units at C-2 and/or C-3 of the main chain, whereas the differences may occur in the distribution of branches along the xylan backbone.

  • comparative study of hemicelluloses obtained by graded Ethanol Precipitation from sugarcane bagasse
    Journal of Agricultural and Food Chemistry, 2009
    Co-Authors: Feng Peng, Jing Bian, Pai Peng, Junli Ren, Runcang Sun
    Abstract:

    The sequential treatment of dewaxed sugarcane bagasse with H(2)O and 1 and 3% NaOH at a solid to liquid ratio of 1:25 (g mL(-1)) at 50 degrees C for 3 h yielded 74.9% of the original hemicelluloses. Each of the hemicellulosic fractions was successively subfractionated by graded Precipitation at Ethanol concentrations of 15, 30, and 60% (v/v). Chemical composition, physicochemical properties, and structures of eight precipitated hemicellulosic fractions were elucidated by a combination of sugar analysis, nitrobenzene oxidation of bound lignin, molecular determination, Fourier transform infrared (FT-IR), (1)H and (13)C nuclear magnetic spectroscopies, and thermal analysis. The results showed that the sequential treatments and graded Precipitations were very effective on the fractionation of hemicelluloses from bagasse. Comparison of these hemicelluloses indicated that the smaller sized and more branched hemicelluloses were extracted by the hot water treatment; they are rich in glucose, probably originating from alpha-glucan and pectic polysaccharides. The larger molecular size and more linear hemicelluloses were dissolved by the alkali treatment; they are rich in xylose, principally resulting from l-arabino-(4-O-methylglucurono)-d-xylans. In addition, noticeable differences in the chemical composition and molecular weights were observed among the graded hemicellulosic subfractions from the water-soluble and alkali-soluble hemicelluloses. The Ara/Xyl ratio increased with the increment of Ethanol concentration from 15 to 60%, and the arabinoxylans with higher Ara/Xyl ratios had higher molecular weights. There were no significant differences in the structural features of the precipitated hemicellulosic subfractions, which are mainly constituted of l-arabino-(4-O-methyl-d-glucurono)xylan, whereas the difference may occur in the distribution of branches along the xylan backbone.

Jing Bian - One of the best experts on this subject based on the ideXlab platform.

  • studies on the starch and hemicelluloses fractionated by graded Ethanol Precipitation from bamboo phyllostachys bambusoides f shouzhu yi
    Journal of Agricultural and Food Chemistry, 2011
    Co-Authors: Pai Peng, Jing Bian, Feng Peng, Feng Xu
    Abstract:

    Starch from bamboo Phyllostachys bambusoides f. shouzhu Yi evaluated by means of solid-state 13C CP/MAS NMR and X-ray diffraction showed a typical B-type pattern with a very low degree of crystallinity (10.9%). In addition to starch, alkali-soluble hemicelluloses were further fractionated by graded Precipitation at Ethanol concentrations of 0 (HA), 15, 30, 45, 60, and 75% (v/v). Chemical composition and structural features of the six hemicellulosic subfractions were investigated by a combination of sugar analysis, GPC, FT-IR, GC-MS, 1D (1H and 13C) and 2D (HSQC) NMR spectra, and thermal analysis. The results showed that the bamboo hemicelluloses were O-acetylated 4-O-methyl-glucuronoarabinoxylans (GAX) consisting of a linear (1→4)-β-d-xylopyranosyl backbone decorated with branches at O-3 of α-l-arabinofuranosyl (5−12 mol %) or at O-2 of 4-O-methylglucuronic acid units and acetyl groups (0.8−11 mol %). The molecular weights of these polysaccharides ranged between 13400 and 67500 g/mol, and the molar ratios...

  • isolation and fractionation of hemicelluloses by graded Ethanol Precipitation from caragana korshinskii
    Carbohydrate Research, 2010
    Co-Authors: Jing Bian, Pai Peng, Feng Peng, Feng Xu
    Abstract:

    Abstract Caragana korshinskii hemicelluloses were isolated with 10% KOH at 25 °C for 10 h from the delignified materials. The alkali-extractable hemicelluloses were then successively sub-fractionated by graded Precipitation at final Ethanol concentrations of 10%, 20%, 30%, 45%, 60%, and 80%, respectively. Neutral sugars and molecular weight analyses of the six hemicellulosic subfractions revealed that the molecular weights and the distribution of branches along the xylan backbone are different among the hemicellulosic fractions obtained in various Ethanol concentrations. The less branched hemicelluloses with large molecules were precipitated in lower Ethanol percentages, while with the increasing Ethanol concentrations, more branched hemicelluloses with low molecular weights were obtained. 1 H and 13 C NMR studies revealed that the hemicellulosic subfraction precipitated at an Ethanol concentration of 45% had a backbone of d -xylose residues and were branched mainly through 4- O -methyl-α- d -glucopyranosyl units.

  • fractional study of alkali soluble hemicelluloses obtained by graded Ethanol Precipitation from sugar cane bagasse
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Feng Peng, Jing Bian, Feng Xu, Pai Peng
    Abstract:

    The two hemicellulosic fractions were subsequentially extracted with 5% and 8% NaOH aqueous solution at a solid to liquid ratio of 1:25 (g mL−1) at 50 °C for 3 h from the water, 1 and 3% NaOH-treated sugar cane bagasse, and subfractionated into six preparations by a graded Ethanol Precipitation method at concentrations of 15%, 30% and 60% (v/v). Sugar composition and molecular weight analysis showed that, with an increasing concentration of Ethanol, hemicellulosic subfractions with both higher Ara/Xyl ratios and higher molecular weights were obtained. In other words, with an increasing Ethanol concentration from 15% to 60%, the Ara/Xyl ratios increased from 0.043 in H1 to 0.088 in H3 and from 0.040 in H4 to 0.088 in H6, and the weight-average molecular weights of hemicellulosic subfractions increased from 42 430 (H1) to 85 510 (H3) g mol−1 and from 46 130 (H4) to 64 070 (H6) g mol−1, respectively. The results obtained by the analysis of Fourier transform infrared, sugar composition, and 1H and 13C nuclear...

  • fractional study of alkali soluble hemicelluloses obtained by graded Ethanol Precipitation from sugar cane bagasse
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Feng Peng, Jing Bian, Pai Peng, Junli Ren, Runcang Sun
    Abstract:

    The two hemicellulosic fractions were subsequentially extracted with 5% and 8% NaOH aqueous solution at a solid to liquid ratio of 1:25 (g mL(-1)) at 50 degrees C for 3 h from the water, 1 and 3% NaOH-treated sugar cane bagasse, and subfractionated into six preparations by a graded Ethanol Precipitation method at concentrations of 15%, 30% and 60% (v/v). Sugar composition and molecular weight analysis showed that, with an increasing concentration of Ethanol, hemicellulosic subfractions with both higher Ara/Xyl ratios and higher molecular weights were obtained. In other words, with an increasing Ethanol concentration from 15% to 60%, the Ara/Xyl ratios increased from 0.043 in H(1) to 0.088 in H(3) and from 0.040 in H(4) to 0.088 in H(6), and the weight-average molecular weights of hemicellulosic subfractions increased from 42 430 (H(1)) to 85 510 (H(3)) g mol(-1) and from 46 130 (H(4)) to 64 070 (H(6)) g mol(-1), respectively. The results obtained by the analysis of Fourier transform infrared, sugar composition, and (1)H and (13)C nuclear magnetic spectroscopy showed that the alkali-soluble hemicelluloses had a backbone of xylose residues with a beta-(1-->4)-linkage and were branched mainly through arabinofuranosyl units at C-2 and/or C-3 of the main chain, whereas the differences may occur in the distribution of branches along the xylan backbone.

  • comparative study of hemicelluloses obtained by graded Ethanol Precipitation from sugarcane bagasse
    Journal of Agricultural and Food Chemistry, 2009
    Co-Authors: Feng Peng, Jing Bian, Feng Xu, Pai Peng
    Abstract:

    The sequential treatment of dewaxed sugarcane bagasse with H2O and 1 and 3% NaOH at a solid to liquid ratio of 1:25 (g mL−1) at 50 °C for 3 h yielded 74.9% of the original hemicelluloses. Each of the hemicellulosic fractions was successively subfractionated by graded Precipitation at Ethanol concentrations of 15, 30, and 60% (v/v). Chemical composition, physicochemical properties, and structures of eight precipitated hemicellulosic fractions were elucidated by a combination of sugar analysis, nitrobenzene oxidation of bound lignin, molecular determination, Fourier transform infrared (FT-IR), 1H and 13C nuclear magnetic spectroscopies, and thermal analysis. The results showed that the sequential treatments and graded Precipitations were very effective on the fractionation of hemicelluloses from bagasse. Comparison of these hemicelluloses indicated that the smaller sized and more branched hemicelluloses were extracted by the hot water treatment; they are rich in glucose, probably originating from α-glucan a...

Qi Wang - One of the best experts on this subject based on the ideXlab platform.

  • new studies on gum ghatti anogeissus latifolia part i fractionation chemical and physical characterization of the gum
    Food Hydrocolloids, 2011
    Co-Authors: Ji Kang, Steve W Cui, Jie Chen, Glyn O Phillips, Qi Wang
    Abstract:

    Abstract This paper describes the fractionation, chemical and physical characterization of processed gum Ghatti (Gatifolia SD), and identifies the source of its surface activity. Four fractions were separated using the gradual Ethanol Precipitation method. With the increase of alcohol concentration, the chemical composition of the fractions exhibited a pattern: arabinose content increased, but the galactose, protein and uronic acid contents decreased in the order of: F50 (50% Ethanol precipitate), F65 (65% Ethanol precipitate), F80 (80% Ethanol precipitate) and FS (the supernatant after 80% Ethanol Precipitation). Rheologically gum ghatti and its fractions exhibited Newtonian flow behavior until gum concentrations reached to 20% (w/v), at which point gum ghatti showed some shear thinning. At the same shear rate and concentration, the apparent viscosities of these fractions decreased in the order: F50 > F65 > F80 > FS. When compared at same concentration, the FS fraction had the highest surface activity relative to the Gatifolia SD, the other fractions and even gum Arabic. Monosaccharide composition and preliminary structural analysis showed that the branching of the polymer increased in the order of F50, F65 and F80. The degree of branching levels, protein and uronic acid content could be responsible for the different solubility of the fractions in alcohol. However, the molecular structure of FS is significantly different from the other fractions. FT-IR spectroscopy revealed no esterified carboxyl group in gum ghatti. Detailed structural elucidation of each fraction will follow.

  • new studies on gum ghatti anogeissus latifolia part iii structure characterization of a globular polysaccharide fraction by 1d 2d nmr spectroscopy and methylation analysis
    Food Hydrocolloids, 2011
    Co-Authors: Ji Kang, Steve W Cui, Jie Chen, Glyn O Phillips, Qingbin Guo, Qi Wang
    Abstract:

    Abstract The structure of a globular gum ghatti fraction (FS) with low surface tension was investigated using methylation–GC–MS, 1D ( 1 H, 13 C) and 2D (COSY, TOCSY, HMQC and HMBC) NMR spectra. FS was obtained from the supernatant after sequential Ethanol Precipitation of aqueous gum ghatti (Gatifolia SD) solutions after 80% (v/v) Ethanol. FS is proposed to be a highly branched polysaccharide with small amount of acetyl substitution: Download full-size image R can be represented by the following groups: →2,3-Man p 1→, →3,4-Glc p 1→, →4-Gal p 1→, T-α- l -Ara f  1→, T-Glc p A1→,T-Gal p 1→ and T- l -Ara p 1→. Galactose has the -β- d configuration, while the arabinose and rhamnose are in α- l form.