Drying and processing protocols affect the quantification of cyanogenic glucosides in forage sorghum

Gleadow, R.M. and EMøldrup, M.E. and Donnell, N.H.O. and Stuart, P.N. (2012) Drying and processing protocols affect the quantification of cyanogenic glucosides in forage sorghum. Journal of the Science of Food and Agriculture, 92 (11). pp. 2234-2238.

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Background: Cyanogenic glucosides are common bioactive products that break down to release toxic hydrogen cyanide (HCN) when combined with specific β-glucosidases. In forage sorghum, high concentrations of the cyanogenic glucoside dhurrin lead to reduced productivity and sometimes death of grazing animals, especially in times of drought, when the dhurrin content of stunted crops is often higher. The aim of this study was to develop harvesting protocols suitable for sampling in remote areas. Results: Dhurrin concentration in air- and oven-dried leaves was the same as in fresh leaves, with no subsequent losses during storage. Dhurrin concentration was halved when leaves were freeze-dried, although activity of the endogenous dhurrinase was preserved. Direct measurement of dhurrin concentration in methanolic extracts using liquid chromatography/mass spectrometry (LC/MS) gave similar results to methods that captured evolved cyanide. A single freezing event was as effective as fine grinding in facilitating complete conversion of dhurrin to cyanide. Conclusion: Direct measurement of dhurrin using LC/MS is accurate but expensive and not appropriate for fieldwork. Air drying provides an accurate, low-cost method for preparing tissue for dhurrin analysis, so long as the specific β-glucosidase is added. It is recommended that comparative studies like the one presented here be extended to other cyanogenic species

Item Type: Article
Uncontrolled Keywords: Sorghum bicolor; Method; Cyanogenic glucoside; Dhurrin; Forage sorghum; Freeze-drying; β-glucosidase; Cyanide; HCN
Author Affiliation: School of Biological Science, Monash University, Melbourne 3800, Australia
Subjects: Crop Improvement
Plant Physiology and Biochemistry > Biochemistry
Divisions: Sorghum
Depositing User: Ms Ishrath Durafsha
Date Deposited: 03 Jun 2014 08:56
Last Modified: 03 Jun 2014 08:56
Official URL: http://dx.doi.org/10.1002/jsfa.5752
URI: http://eprints.icrisat.ac.in/id/eprint/13221

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