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

^†Corresponding author. Phone: +61 2 6246 4962. E-mail: Hunter.Laidlaw@gmail.com
CSIRO Food Futures Flagship, GPO Box 93, North Ryde, NSW 1670, Australia, and CSIRO Plant Industry, GPO Box 1600, ACT 2601, Australia.

Phloroglucinol 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.