Evidence for wheat, rye, and barley presence in gluten free foods by PCR method - comparison with ELISA method

Abstract

Mašková E., Paulíčková I., Rysová J., Gabrovská D. (2011): Evidence for wheat, rye, and barley presence in gluten free foods by PCR method -comparison with ELISA method. Czech J. Food Sci., 29: 45-50.A method of the evidence for the presence of wheat, rye, and barley in gluten free foods, based on the polymerase chain reaction (PCR), was validated. DNA was isolated from foods by chaotropic solid phase extraction. The PCR method applied was focused on the intron of the chloroplast gene trnl and utilised primers WBR11 and WBR13. Electrophoresed wheat and rye DNAs were characterised by a 201 bp fragment, barley DNA by a 196 bp fragment. The validated PCR method was applied to the selection of 18 gluten free foods, previously found by ELISA method to contain 1 mg or more of gliadin per 100 g food. The presence of wheat was confirmed by PCR method in all foods analysed. The comparison with the results obtained by ELISA method reliably verified the detection limit of PCR method, i.e., 0.02% wheat.

Combined effects of matrix and gene marker on the real‐time PCR detection of wheat

“…The highlighted sensitivity values were generally in good agreement with the results reported in the literature. In the case of soya bean matrix, the worst scenario, the obtained sensitivities of 50 mg kg −1 , using the α2‐gliadin gene, and 500 mg kg −1 with other genes, were much improved compared with the reported level of 1000 mg kg −1 for wheat in soya bean matrix (Olexova et al ., ; Maskova et al ., ). Concerning maize matrix, a better sensitivity was also obtained using the α2‐gliadin system (10 mg kg −1 ) than the reported level of 50 mg kg −1 (Yamakawa et al ., ).…”

“…Usually, this variation does not exceed one order of magnitude, allowing the correlation between DNA and amount of gluten (Luber et al, 2014), thus presenting excellent alternative methods to ELISA. To determine wheat in gluten-free products, the selected target sequences could be both genes coding for an allergenic protein (glutenins, gliadins) (Sandberg et al, 2003;Debnath et al, 2009;Zeltner et al, 2009) or simply, a species-specific region in the genome of the allergenic food (Tilley, 2004;Olexova et al, 2006;Piknova et al, 2008;Maskova et al, 2011;Pegels et al, 2015). Despite several efforts to detect trace amounts of wheat in food, very few studies reached the limit of 20 mg kg À1 set by the legislation to discriminate safe products for coeliac patients (Regulation (EC) No.…”

Cereal Crops Are not Created Equal: Wheat Consumption Associated with Obesity Prevalence Globally and Regionally

“…The data were selected in consideration of their fulfilment of 1) completeness of data across all analysed variables, 2) the most updated and recent datasets available, 3) major food types: meat, fat, sugar and refined cereals (wheat) that were indicated in the literature to have relationships with obesity. Barley and rye also contain obesity associated gluten like wheat [40] , but we did not include them in our study due to their extremely low availabilities in limited areas in the world. Following these conditions, country-level data on obesity prevalence in 2014, cereal availability in 2011 (mixed cereals, wheat, rice, and maize), and potential confounders (meat, sugar, fat, soy, total calories and GDP) in 2011 were matched.…”