Structural analysis of arabinoxylans isolated from native and malted finger millet (Eleusine coracana, ragi)

Rao, M. V. L.; Muralikrishna, G.

doi:10.1016/j.carres.2004.07.005

Cited by 45 publications

(19 citation statements)

References 20 publications

(13 reference statements)

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“…A low intensity signal for C‐6 carbonyl group, pertaining to O‐Me‐a‐D‐glucuronic acid arabinose residue was noticed at 178.6 ppm which indicated the presence of XOS with lesser branching or side groups. Similar observations have been made with the 13 C NMR spectra for ragi arabinoxylans (Subba Rao & Muralikrishna, ) and enzymatically derived XOS from sugarcane bagasse (Bian et al, ). On the basis of NMR results, the major XOS derived from wheat bran hydrolysis composed of xylobiose and xylotriose.…”

Section: Resultssupporting

confidence: 82%

Production of a thermostable and alkali resistant endoxylanase byBacillus subtilisDFR40 and its application for preparation of prebiotic xylooligosaccharides

2018

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Xylanases produced by microorganisms hydrolyze xylan, into xylose or xylooligosaccharides (XOS). Xylan is an abundant noncellulosic polysaccharide found in the plant biomass. The enzyme is of great practical importance for the conversion of xylan containing agricultural residues into XOS for use as prebiotics. A Bacillus subtilis strain DFR40 a generally recognized as safe (GRAS) organism was found to produce extracellular xylanase in a growth medium containing wheat bran, mineral salts, peptone, and yeast extract at pH 7.0. The optimum activity of the enzyme was around 100°C and pH 9.0 with stability over a broad range of pH (7.0–12.0) displaying enzyme stability of more than 70% even after pre‐incubation at 55–85°C for 30 min. The enzyme hydrolyzed wheat bran into short chain XOS as revealed by TLC, HPLC, FT‐IR, and NMR analysis. Practical applications The thermostable and alkali resistant characteristics of extracted xylanase along with ability to hydrolyze wheat bran for the production of xylooligosaccharides (XOS), for use as prebiotic ingredients in food, are relevant in the present health conscious worldwide scenario. XOS are emerging class of prebiotics with thermal resistance up to 100°C, and are suitable for incorporating into thermally processed food products with extended shelf life. The XOS preparation was also found suitable suggesting the prebiotic nature of XOS on known probiotic bacterial strains. The study also indicates a valuable application for wheat bran, a cheap agro residue for further cost effective scale up of XOS production. The xylanase produced is of significance as the producing bacterium is a GRAS organism for further scale‐up of the processes of enzyme and XOS production.

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Section: Resultssupporting

confidence: 82%

Production of a thermostable and alkali resistant endoxylanase byBacillus subtilisDFR40 and its application for preparation of prebiotic xylooligosaccharides

2018

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“…Substitutions at C-2 and C-2/C-3 of xylose residues with arabinosfuranoses were also noted in these heavily substituted arabinoxylans (15,16). 4-(O-Me)-glucuronic acid is the other major substituent connected to C-2 of xylose residues in finger millet arabinoxylans (15).…”

Section: Introductionmentioning

confidence: 88%

“…Several methods have been developed for the isolation and characterization of water-extractable and waterunextractable arabinoxylans from major food crops such as barley (10), wheat (11), rice (12), and sorghum (13,14). However, except for a few recent papers, not many studies have been carried out on the structural features of arabinoxylans from millets such as finger millet (15) and pearl millet (16) and their malts, the major source of food in developing countries such as India and Africa. The reported structural aspects of finger millet and pearl millet arabinoxylans demonstrated the presence of a β-(1,4)-linked xylopyranoside backbone substituted primarily with arabinofuranoses at C-3 via R-(1,3) linkage.…”

Section: Introductionmentioning

confidence: 99%

Hemicelluloses of Ragi (Finger Millet, Eleusine coracana, Indaf-15): Isolation and Purification of an Alkali-Extractable Arabinoxylan from Native and Malted Hemicellulose B

Rao

Muralikrishna

2006

J. Agric. Food Chem.

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Hemicelluloses (A and B) were isolated from an Indo-African hybrid variety of finger millet (ragi, Eleusine coracana) by extracting the starch-free residue with 10% sodium hydroxide under a continuous stream of nitrogen, and changes in their sugar composition during malting for 96 h were studied. Hemicellulose B, obtained in higher yield from both native (N) and malted (M) flours, was found to be completely soluble in water, richer in uronic acid, and more viscogenic than hemicelullose A. Fractional precipitation of hemicellulose B by ammonium sulfate resulted in four precipitable fractions (F-60, F-70, F-80, and F-100) and a nonprecipitable (NP) fraction varying in their yield and arabinose, xylose, galactose, and glucose contents. A progressive increase in the pentose-to-hexose ratio (P:H) from 0.42:1.0 in F-60 to 1.94:1.0 in NP was observed in native hemicellulose B fractions; however, in malted hemicellulose B the P:H ratio increased from 0.43:1.0 in F-60 to 1.56:1.0 in F-80 and then decreased to 1.13:1.0 in NP. The major fraction, F-70 (N, 44.5%; M, 38.5%), was separated into eight subfractions on DEAE-cellulose by successive elution with water, ammonium carbonate (AC) (0.1, 0.2, and 0.3 M AC), and sodium hydroxide (0.1 and 0.2 M) differing in their yield and neutral sugar composition. The purity of the major glucuronoarabinoxylan fraction (0.1 M AC eluted) was ascertained by Sepharose CL-4B, HPSEC, cellulose acetate, and capillary electrophoresis methods. A significant decrease in the molecular mass of arabinoxylan from 1200 to 1120 kDa upon malting for 96 h is an indication of cell wall degradation by the inducible cell wall degrading enzymes.

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“…The peak multiplicity in the 1120-1000 cm À1 , is a typical characteristic of highly substituted Table 4 Weight-average (M w ) and number-average (M n ) molecular weights and polydispersity (M w /M n ) of the hemicellulosic fractions. arabinoxylans, and the arabinose substitution at C-3 of xylose residues gives a band at 1173 cm À1 (Subba & Muralikrishna, 2004). An absorption band at 903 cm À1 is clearly visible in the spectra of H 2B , H 3B , and H 4B , indicating that the presence of dominant b-glycosidic linkages between the sugar units in these hemicellulosic fractions.…”

Section: Ft-ir Spectramentioning

confidence: 98%

Comparative characterization of degraded and non-degradative hemicelluloses from barley straw and maize stems: Composition, structure, and thermal properties

Jin

Ren

Peng

et al. 2009

Carbohydrate Polymers

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Structural analysis of arabinoxylans isolated from native and malted finger millet (Eleusine coracana, ragi)

Cited by 45 publications

References 20 publications

Production of a thermostable and alkali resistant endoxylanase byBacillus subtilisDFR40 and its application for preparation of prebiotic xylooligosaccharides

Production of a thermostable and alkali resistant endoxylanase byBacillus subtilisDFR40 and its application for preparation of prebiotic xylooligosaccharides

Hemicelluloses of Ragi (Finger Millet, Eleusine coracana, Indaf-15): Isolation and Purification of an Alkali-Extractable Arabinoxylan from Native and Malted Hemicellulose B

Comparative characterization of degraded and non-degradative hemicelluloses from barley straw and maize stems: Composition, structure, and thermal properties

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