Proposal for C-Hordein as Reference Material in Gluten Quantification
- 6 March 2017
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of Agricultural and Food Chemistry
- Vol. 65 (10), 2155-2161
- https://doi.org/10.1021/acs.jafc.6b05061
Abstract
The concentration of residual barley prolamin (hordein) in gluten-free products is overestimated by the R5 ELISA method when calibrated against the wheat gliadin standard. The reason for this may be that the composition of the gliadin standard is different from the composition of hordeins. This study showed that the recognition of whole hordein by R5 antibody mainly came from C-hordein, which is more reactive than the other hordeins. The proportion of C-hordein in total hordein ranged from 16 to 33% of common Finnish barley cultivars used in this study and was always higher than that of ω-gliadin, the homologous protein class in the gliadin standard, which may account for the overestimation. Thus, a hordein standard is needed for barley prolamin quantification instead of the gliadin standard. When gluten-free oat flour was spiked with barley flour, the prolamin concentration was overestimated 1.8–2.5 times with the gliadin standard, whereas estimates in the correct range were obtained when the standard was 40% C-hordein mixed with an inert protein. A preparative-scale method was developed to isolate and purify C-hordein, and C-hordein is proposed as a reference material to calibrate barley prolamin quantification in R5-based assays.Keywords
Funding Information
- Tekes
This publication has 33 references indexed in Scilit:
- Quantification of Hordeins by ELISA: The Correct Standard Makes a Magnitude of DifferencePLOS ONE, 2013
- Measuring Hordein (Gluten) in Beer – A Comparison of ELISA and Mass SpectrometryPLOS ONE, 2013
- What is in a Beer? Proteomic Characterization and Relative Quantification of Hordein (Gluten) in BeerJournal of Proteome Research, 2011
- Gluten contamination in the Canadian commercial oat supplyFood Additives & Contaminants: Part A, 2011
- Patterns of Barley Grain Development in Spain and Scotland and Their Implications for Malting QualityCereal Chemistry Journal, 1997
- Cultivar and environmental effects on malting quality in barleyAustralian Journal of Agricultural Research, 1995
- The ratio of B to C hordeins in barley as estimated by high performance liquid chromatographyJournal of the Science of Food and Agriculture, 1987
- Identification of γ‐type hordeins in barleyFEBS Letters, 1985
- The effect of nitrogen nutrition on the lysine content and protein composition of barley seedsJournal of the Science of Food and Agriculture, 1982
- Varietal identification of single seeds of barley by analysis of hordein polypeptidesJournal of the Science of Food and Agriculture, 1978