Investigation of the effects of food processing and matrix components on the analytical results of ELISA using an incurred gliadin reference material candidate

Abstract

Disorders induced by cereal proteins (e.g. wheat allergy, celiac disease) are widespread in human population. Since their only effective treatment is the avoidance of the problematic proteins, patients have to be familiar with the composition of food products. For checking special foods produced for them, proper analytical methods are necessary. At the moment, in gluten analysis there are no reference methods and reference materials which model real food matrices. During the production and experimental utilisation of our previously developed reference material candidate, numerous questions emerged. As our model product is a real food matrix, interactions can be present between gluten proteins and other macro and micro components. Fat content of the baked cookies is almost 20%, which might affect the results of ELISA measurements. The detectable gluten content is signifi cantly increasing after the defatting procedure, as a pre-treatment of samples. Moreover, baking is a common food processing step that might modify the structure of gluten proteins leading to denaturation and aggregation. In the soluble protein fraction the amount of low molecular weight proteins increases, while that of high molecular weight proteins decreases during the baking procedure.

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

“…However, in cookies considerably different values were observed compared to dough samples in a kit-dependent manner. The experienced deviation of the gliadin contents could be due to an ineffi cient extraction method or any modifi cations infl uencing changes in antibody-antigen binding (BUGYI et al, 2013;SHARMA et al, 2013;TÖRÖK et al, 2015). The effect of protein source and harvest year on gliadin recoveries is dependent on the level of processing factor according to ANOVA results.…”

“…For effi cient extraction of prolamins from processed products, extraction solvents containing reducing and disaggregating agents were developed (GARCÍA et al, 2005;GESSENDORFER et al, 2010;MENA et al, 2012). Matrix effects caused by different macro and micro components of foods may also change the extraction yield and immunochemical reactivity of gluten proteins through the formation of complexes or resistant aggregates (SCHERF & POMS, 2016;TÖRÖK et al, 2014TÖRÖK et al, , 2015.…”

Identification of key effects causing weak performance of allergen analysis in processed food matrices

“…Ground raw dough and cookie samples were defatted using a Soxtec extractor (Soxtec System HT, 1043 Extraction Unit, Tecator AB, Sweden) according to a procedure described elsewhere (TÖRÖK et al, 2014a). …”

Applicability of ELISA methods for high gluten-containing samples

“…As a result, these factors also affect the relative amount of epitopes that are recognized by antibodies commonly used in gluten ELISA test kits (HAJAS et al, 2018;SCHOPF & SCHERF, 2018). Complexity of the food matrices and the effects of food processing on the target proteins are also restraining factors of gluten analysis (BESLER et al, 2001;TÖRÖK et al, 2015).…”