A rapid method of dietary fibre estimation in wheat products

Bell, Brenda

doi:10.1002/jsfa.2740360910

Cited by 24 publications

(23 citation statements)

References 6 publications

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“…Degradation products released by the a-amylase treatment were removed by washing three times with 80% ethanol. Cell wall material was hydrolyzed by 0.5 M sulfuric acid at 100°C for 30 min, and pentose sugars were determined essentially as described by Bell (1985). The colorimetric reagent was prepared by mixing 11 mL of acetic acid, 0.2 mL of HCl, 0.1 mL of 1.5% (w/v) Glc, and 0.5 mL of 20% (w/v; in ethanol) phloroglucinol.…”

Section: Analysis Of Pentose Sugars In the Cell Wallmentioning

confidence: 99%

“…One milliliter of the reagent was added to 0.2-mL samples containing zero to 100 mg of pentose sugars, the mixture was heated at 100°C for 25 min and cooled for 5 min, and absorption was measured at 552 and 510 nm. The difference between A 552 and A 510 was taken for the calculation of pentose sugar concentration (Bell, 1985). Xyl was used as standard in the assay.…”

Section: Analysis Of Pentose Sugars In the Cell Wallmentioning

confidence: 99%

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The Genetics, Transcriptional Profiles, and Catalytic Properties of UDP-α-d-Xylose 4-Epimerases from Barley

et al. 2010

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Cell walls in the grasses contain relatively high levels of heteroxylans and, in particular, arabinoxylans. Enzymes and corresponding genes that are involved in the provision of sugar nucleotide substrates represent potential control points for arabinoxylan biosynthesis. Following expressed sequence tag database analyses, three genes encoding barley (Hordeum vulgare) UDP-D-xylose 4-epimerases (UXE; EC 5.1.3.5), designated HvUXE1, HvUXE2, and HvUXE3, were cloned and their positions on genetic maps defined. To confirm the identity of the genes, a cDNA construct encoding HvUXE1 was expressed in Pichia pastoris. The purified, recombinant HvUXE1 catalyzed the freely reversible interconversion of UDP-a-D-xylopyranose and UDP-b-L-arabinopyranose, with K m values of 1.8 and 1.4 mM, respectively. At equilibrium, the ratio of substrate to product was approximately 1:1. Each molecule of heterologously expressed HvUXE1 enzyme contained about one molecule of noncovalently bound NAD + . Molecular modeling provided a structural rationale for the substrate specificity of the UDP-D-xylose 4-epimerase and, in particular, explained its tight specificity for UDP-xylose compared with other sugar nucleotide epimerases. Quantitative transcript analyses performed for each of the three genes in a range of organs showed, inter alia, that in developing barley endosperm HvUXE1 and HvUXE3 mRNA levels peaked at a time when UDP-a-D-xylopyranose synthase (UXS) transcripts also reached a maximum and when arabinoxylan biosynthesis was initiated. Furthermore, the data revealed that the transcription of HvUXE and HvUXS gene family members is coordinated with the incorporation of pentose sugars onto cell walls in barley leaves, roots, and developing endosperm.

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Section: Analysis Of Pentose Sugars In the Cell Wallmentioning

confidence: 99%

Section: Analysis Of Pentose Sugars In the Cell Wallmentioning

confidence: 99%

The Genetics, Transcriptional Profiles, and Catalytic Properties of UDP-α-d-Xylose 4-Epimerases from Barley

et al. 2010

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“…TP of a test sample was calculated based on the absorbance differences at 552 and 510 nm using the calibration curve. TP of whole grain wheat, bran, and shorts fractions were determined using the method of Bell (1985) which is similar to Douglas' procedure but implements sample prehydrolysis using 0.5M sulfuric acid, which is necessary to completely solubilize bran particles that would otherwise interfere with subsequent absorbance measurements.…”

Section: Determination Of Total Pentosans and Water-extractable Pentomentioning

confidence: 99%

Composition and Distribution of Pentosans in Millstreams of Different Hard Spring Wheats

et al. 2006

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Cereal Chem. 83(2):161-168Six commercially grown samples of hard spring wheat were milled using a tandem Buhler laboratory mill. Individual flour streams and branny by-products, as well as whole-grain wheat and straight-grade flour, were characterized in terms of total (TP), water-extractable (WEP), and water-unextractable (WUP) pentosans. One representative cultivar sample was analyzed for its ratio of arabinose to xylose (A/X). TP and WEP of whole grain wheat of the six samples had ranges of 5.45-7.32% and 0.62-0.90% (dm), respectively. Neither TP nor WEP of whole grain was related to ash content variation. There was significant variation in the distribution and composition of pentosans in 16 millstreams of all the wheat samples, including bran and shorts fractions; TP and WEP contents had ranges of 1.69-32.4% and 0.42-1.76% (dm), respectively. When ash contents exceeded ≈0.6% (dm), strong positive correlations were obtained between ash and TP contents, and between ash and WUP contents for all the millstreams. Among bran and shorts fractions, TP and WUP content increased in the order of coarse bran > fine bran > shorts; while WEP, WEP/WUP and A/X showed the opposite pattern of variation of shorts > fine bran > coarse bran. Bran and shorts fractions had pentosan contents several times higher than would be predicted from the relationship between pentosan and ash contents of the flour streams. Pentosans therefore represented a much more sensitive marker of flour refinement compared with ash content. Pentosans of endosperm were substantially different in their extractability and composition from those of bran. On this basis, different functionalities of pentosans of bran and endosperm would be expected. Results demonstrated the importance of milling extraction and millstream blending in the functionality and quality of wheat flour for breadmaking.The major nonstarch polysaccharides (NSP) of wheat are pentosans, which originate in the cell walls of endosperm and bran. Arabinoxylan (AX), the predominant constituent of pentosans, consists of a β-(1→4)-linked D-xylopyranose polymer backbone with frequent branching of L-arabinofuranose residues at O-3 (Perlin 1951a and 1951b) or O-2 and O-3 (Gruppen et al 1992). Arabinoxylan polymer also contains the phenolic compound ferulic acid which is esterified to arabinose residues at O-5 (Fausch et al 1963). Ferulic acid is the key component involved in oxidative gelation of pentosans, a cross-linking reaction believed to be unique to the water-extractable pentosan (WEP) fraction (Neukom and Markwalder 1978;Hoseney and Faubion 1981). WEP and water-unextractable pentosan (WUP) comprise ≈25 and 75%, respectively, of TP present in wheat flour (Meuser and Suckow 1986).The behavior of pentosans in aqueous solutions relates to the shape and size of the polymers and is largely determined by the complex nature of degree of substitution and contiguity of substitution of AX molecules (Gruppen et al 1993). In general, a higher degree of substitution, i.e., higher ratio of arabinose (A) to...

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“…Kiszonas et al (2012) undertook a thorough assessment of this assay to further optimize several parameters including reaction constituents and reaction times. The assay has also been split into a two-step process comprising an initial pentosan hydrolysis step followed by the monosaccharide conversion to furfural and reaction with phloroglucinol (Bell 1985). Whereas the conversion to furfural requires high heat (a boiling water bath is typically used), it appears that this temperature was also retained for the initial hydrolysis step (Bell 1985;Zhang et al 2010;Butardo et al 2011).…”

mentioning

confidence: 99%

“…Quantification of arabinoxylan has been achieved through a number of methods, including colorimetric assays (Douglas 1981;Bell 1985), gas chromatography (Gebruers et al 2009), and high-performance anion-exchange chromatography coupled to pulsed amperometric detection (Houben et al 1997;Nguyen et al 2011). Phloroglucinol was first described in the quantification of five-carbon monosaccharides by Wheeler and Tollens (1889) and for hydrolyzed pentosans several years later (Kröber et al 1902a(Kröber et al , 1902b.…”

mentioning

confidence: 99%

NOTE: Hydrolysis Temperature Affects the Phloroglucinol Assay for Arabinoxylan Quantification in Wheat Flour

Laidlaw¹,

Kooij-Liu

Jobling

2015

Cereal Chem

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Cereal Chem. 92(1):54-56Phloroglucinol has a long history of use for the determination of pentose monomer content. Its application to cereal chemistry has been developed over several decades; however, no studies on the potential influence of hydrolysis temperature have yet been reported. We demonstrate the effect of hydrolysis temperature on the phloroglucinol assay for the measurement of pentosans in both refined and wholemeal wheat flours. In refined flour, monosaccharide degradation and interfering reactions from starch appear to effectively reduce the absorbance difference used to determine pentosan content. The presence of glucose in the reaction is also shown to provide stability to the reaction products. The potential impact of these factors on the determination of pentosan content needs to be considered when interpreting the results obtained using phloroglucinol-based methods.

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A rapid method of dietary fibre estimation in wheat products

Cited by 24 publications

References 6 publications

The Genetics, Transcriptional Profiles, and Catalytic Properties of UDP-α-d-Xylose 4-Epimerases from Barley

The Genetics, Transcriptional Profiles, and Catalytic Properties of UDP-α-d-Xylose 4-Epimerases from Barley

Composition and Distribution of Pentosans in Millstreams of Different Hard Spring Wheats

NOTE: Hydrolysis Temperature Affects the Phloroglucinol Assay for Arabinoxylan Quantification in Wheat Flour

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