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Detection of gluten in food by a novel immunoturbidimetric assay

Current methods of gluten determination in food are based on non automatic, time consuming, poorly standardized and expensive elisa assays. We propose an immunoassay based on agglutination of microparticles, resulting in a more standardized, reliable, automatic and nonexpensive method of detection.

INTRODUCTION Gluten is the most important storage protein of the wheat's seed and other graminae like barley, rye and oats, or any of their variants ans hybrids (espelt, kamut or triticale). Wheat gluten is formed by glutenins and gliadins (90%), lipids (8%) and carbohydrates (2%), being gliadins the proteins responsible for health disorders related to gluten. Currently, three main forms of such disorders are known: wheat allergy, autoimmune disorder (including celiac disease, dermatitis herpetiformis and gluten ataxia) and non-celiac gluten sensitivity. Gluten related disorders can affect up to 1% of population, with guten free diet as the only effective treatment. Gluten is used in food industry because of its unique viscolastic properties, which give elasticity to the flour mass and it allows bread to gain volume, elasticity and sponginess. Gluten is also used as an additive in many processed food preparations. Thus, an accurate gluten measurement and product labelling is mandatory for a proper follow up of the gluten free diet. Current UE legislation stands that the only products that can be labeled as gluten free are those with a gluten content lower than 20 ppm, and that tose between 20 and 100 ppm, can be labeled as "very low content in gluten". A preliminary market study shows that over 6 milion tests are performed annually worldwide with an average cost of 8€ per test. BACKGROUND Currently, gluten quantification is achieved by ELISA techniques, either in the competitive or sandwhich format. According to the Codex Alimentarius (promoted by WHO and FAO and reviewed in 2008), the technique used should be based on an antibody specific for the protein residues that are considered toxic for the gluten sensitive patients, and it must not react with other cereal proteins or food components (R5 or G12 antibodies are recommended). Due to the lack of standardization, specially related with the sample extraction procedure and the specificity of the antibody used, results obtained by different manufacturers are not entirely equivalent. This stands for a good reason to move forward to a method for gluten detection of easier standardization, like immunoturbidimetry proposed by this project. Codex Alimentarius stands that any method intended for gluten peasurement should have a limit of detection equal or below 10 ppm, that is, low enough to ensure the absence of gluten in gluten free food. It is well known that ELISA technique provides a sensitivity good enough to fulfill the expectations of the regulation, but the inability of automation together with the long times of completion of the test, causes the need to work out new approaches. OBJECTIVE The objective of the project is the obtaining of an immunoturbidimetric reagent based on specific antibodies (recommended by Codex Alimentarius) and the corresponding calibrators and controls. In this kind of reagents, the antibody is immobilized on the surface of latex microparticles (less that 1µm diameter) which aggregate in the presence of the antigen, in this case, gluten. The degree of agglutination is proportional to the amount of gluten inthe sample and can be monitorized and quantified by means of a spectophotometer. Immunoturbidimetric reagents are easy to standardize and allow the execution of a high amount of tests in a short period of time by using an autoanalyzer. As part of the procedure, the extraction of the gluten from the sample to be analyzed is a key point to succeed. Different food matrices need different approaches and the final reagent should be able to perform with the most significant in the field of food safety. The nature of the project demands both partners to work together to make compatible reagent and extraction procedures and finnally achieve a successfull gluten determination.
Acronym: 
IGLUTEN
Project ID: 
12 235
Start date: 
01-07-2018
Project Duration: 
18months
Project costs: 
270 000.00€
Technological Area: 
Food quality and safety
Market Area: 
Medical/health

Raising the productivity and competitiveness of European businesses through technology. Boosting national economies on the international market, and strengthening the basis for sustainable prosperity and employment.