ELISA response and gliadin composition of different wheat cultivars grown in multiple harvest years

Abstract

In special dietary products for people intolerant to gluten, gluten content is not supposed to exceed the regulatory thresholds. Enzyme-linked immunosorbent assays (ELISAs) are routinely used to quantitate gluten in these products. They measure gliadin/gluten with high specifi city and sensitivity, but they have some limitations. Quantitative and qualitative variability of the target proteins among wheat cultivars is a factor that may cause inaccurate results. One of the aims of this work was to characterize the protein composition of fi ve wheat cultivars grown in multiple harvest years and their blends by reversed-phase high-performance liquid chromatography (RP-HPLC). The gliadin/gluten content of these wheat fl ours was also analysed with two commercial ELISA kits. The effect of differences in protein profi les between the fl ours from an individual cultivar and the blend of fi ve cultivars, harvest years, as well as processing procedures (dough forming and baking) on the results of two ELISA kits was investigated and their relative magnitude was determined. Among the factors investigated, the differences between fl ours had the greatest impact on gliadin recoveries.Keywords: wheat fl our, protein composition, gluten-free, gliadin/gluten, incurred matrix, ELISAThe ingestion of food from gluten-containing grains can trigger a number of harmful reactions in susceptible individuals, e.g. celiac disease, wheat allergy, and non-celiac gluten sensitivity. Gluten (especially its prolamin fraction) from wheat, rye, and barley is the precipitating factor for celiac disease . Patients must eliminate these grains from their diet, because currently this is the only effective strategy to avoid the symptoms (SABATINO et al., 2013). Two thresholds are defi ned: the terms 'gluten-free' and 'very low gluten' mean that the gluten content in these products is below 20 and 100 mg kg -1, respectively (COMMISSION OF THE EUROPEAN COMMUNITIES, 2009). Reliable analytical methods are needed to assess the gluten content of these products and to enforce regulations. Currently, immunochemical assays (enzyme-linked immunosorbent assays (ELISAs) and lateral fl ow devices (LFDs)) are the preferred methods for determining such low amounts of protein. However, gluten quantitation with ELISA is accompanied by numerous problems, because gluten is a complex mixture of heterogeneous proteins with different solubility, composition, and immunoreactivity (DIAZ- .Most commercial gluten immunoassays are based on determining prolamins, which are soluble in aqueous alcohols (SCHERF & POMS, 2016). Although the primary structure of prolamins appears to be relatively stable, food processing might induce post-translational * To whom correspondence should be addressed. Phone: +36-1-463-1419; fax: +36-1-463-3855; e-mail: tomoskozi@mail.bme.huThis is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 License, which permits unrestricted use, distribution, and reproduction in any medium for non-commercial purposes, provid...

Isolation and characterization of gluten protein types from wheat, rye, barley and oats for use as reference materials

“…The wheat, rye, barley and oat flours were mixtures of four cultivars each to account for the genetic variability between different cultivars [ 38 ]. The cultivars were selected based on their production yields relative to the total production of winter wheat, rye, winter and summer barley, and oats in the year 2012 in Germany to include the most relevant cultivars (cumulative production share for wheat: 16%, rye: 53%, barley: 35%, oats: 41%) [ 39 ].…”

Targeted liquid chromatography tandem mass spectrometry to quantitate wheat gluten using well-defined reference proteins

“…To select marker peptides from wheat, a wheat flour mixture of four cultivars widely grown in Germany was used to include genetic variability between different cultivars [ 22 , 27 ]. The cultivars were selected based on their production yields relative to the total production of winter wheat, in the year 2012 in Germany to include the most relevant cultivars (cumulative production share for wheat: 16%) [ 28 ].…”

Quantitation of the immunodominant 33-mer peptide from α-gliadin in wheat flours by liquid chromatography tandem mass spectrometry

“…To see whether harvest year or cultivar had a greater influence on 33-mer contents, four wheat cultivars (Mv Magvas, Mv Mazurka, Mv Verbunkos, and Yumai-34) grown at the same location in Hungary (Martonvásár) and harvested in three years (2011, 2012, and 2014) 35 were studied. The harvest year significantly influenced the 33-mer contents (p < 0.001), whereas the cultivars did not (p = 0.391).…”