Estimation of Dietary Gluten Content using Total Protein in Relation to Gold Standard Testing in a Variety of FoodsEsther Assor1*, Jolie Davies-Shaw1, Margaret A. Marcon2 and Farid H. Mahmud1
- *Corresponding Author:
- Esther Assor
Hospital for Sick Children
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Toronto, ON, Canada M5G 1X8
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E-mail: [email protected]
Received date: July 06, 2014; Accepted date: July 24, 2014; Published date: July 26, 2014
Citation: Assor E, Davies-Shaw J, Marcon MA, Mahmud FH (2014) Estimation of Dietary Gluten Content using Total Protein in Relation to Gold Standard Testing in a Variety of Foods. J Nutr Food Sci 4:296 doi: 10.4172/2155-9600.1000296
Copyright: © 2014 Assor E, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Objective: To compare the accuracy of the Osborne calculation for estimating gluten content in food in relation a laboratory (ELISA) based method.
Methods: We evaluated 25 commonly consumed gluten-containing food products for ELISA testing of gluten to determine analyzed gluten content. This was compared with calculated gluten content (using the Osborne method) which was determined as 80% of the plant protein content of each food item using nutrition information. Correlation coefficient (r), along with a 95% confidence interval (CI) and Bland Altman plots were used to estimate the level of agreement between calculated and analyzed gluten.
Results: A reasonable overall correlation coefficient of r = 0.46 a 95% CI (0.08 – 0.73, R2 = 0.22) was seen. We observed that variability in the Osborne (calculated) and analyzed gluten increased as the average gluten content increased and the average difference was not constant over the range of gluten measurements. In addition, the calculated gluten measure tended to be higher than analyzed and thus overestimated gluten content (net overestimation was 3.3 g (95% CI -4.0 to 10). Stronger correlations were observed in foods with a gluten content that was lower than the total protein content (N=18, r=0.70, 95% CI=0.35 to 0.88, R2 = 0.49).
Conclusions: These findings indicate that the Osborne (calculated) to analyzed gluten shows a reasonable correlation in foods with lower gluten content (less than 5 g gluten), and that the Osborne method is a practical way to estimate gluten content.