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Galera C, Salagre C, López A. Validation of the GlutenTox® ELISA Rapid G12 Test Kit for Determination of Gluten in Select Non-Heat-Processed Matrixes and Heat-Processed Matrixes: AOAC Performance Tested MethodSM 042301. J AOAC Int 2023; 106:1478-1504. [PMID: 37458481 PMCID: PMC10628967 DOI: 10.1093/jaoacint/qsad081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 06/23/2023] [Indexed: 11/08/2023]
Abstract
BACKGROUND The GlutenTox® ELISA Rapid G12 test kit is a quantitative method designed for the determination of the immunotoxic fraction of gluten in food samples. OBJECTIVE To obtain AOAC Performance-Tested MethodsSM certification for the method for the detection and quantification of gluten from wheat, barley, and rye flours in select foods (non-heat-processed) and incurred (heat-processed) matrixes. METHODS The method was evaluated following the Guidelines for Validation of Quantitative Gluten Methods, with Specific Examples for ELISA Assays. The validation study was conducted at Hygiena Diagnóstica España using five food matrixes (soy flour, corn bread, seasoning mix, rolled oats, and evaporated milk) artificially contaminated with gluten from wheat, barley, or rye flour at different concentrations: 0, 5, 10, and 20 mg/kg. For each matrix and gluten contamination level, five or six individually extracted test portions were analyzed. A second bread matrix was prepared by baking a gluten-free bread mix spiked at 0, 20, and 30 mg/kg gluten from wheat, barley, or rye flour for incurred matrix testing. Ten individually extracted test portions were tested for each incurred bread and contamination level of gluten. RESULTS The method met the AOAC performance requirements for detection and quantification of wheat gluten in the selected food matrixes, incurred bread sample, and spike levels of wheat gluten, showing an acceptable recovery. When tested with barley and rye flours, most of the results showed acceptable recoveries or a slight overestimation, depending on the matrix and gluten concentration. Method developer and independent laboratory results were comparable. CONCLUSIONS The validation study demonstrated that the test kit is a reliable, accurate, quick, and easy-to-use method for the detection and quantification of gluten concentration in food and incurred matrixes from wheat, barley, and rye flours. HIGHLIGHTS Most reagents provided in the kit are at ready-to-use concentrations.
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Affiliation(s)
- Carlos Galera
- Quality Department, Hygiena Diagnóstica España, S.L.U, Calle Cañada Real 31-35, P.I. Parque Plata, Camas (Sevilla), 41900, España
| | - Claudia Salagre
- Quality Department, Hygiena Diagnóstica España, S.L.U, Calle Cañada Real 31-35, P.I. Parque Plata, Camas (Sevilla), 41900, España
| | - Ana López
- Quality Department, Hygiena Diagnóstica España, S.L.U, Calle Cañada Real 31-35, P.I. Parque Plata, Camas (Sevilla), 41900, España
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Schirmer TM, Scherf KA. Influence of baking conditions on the extractability and immunochemical detection of wheat gluten proteins. Curr Res Food Sci 2022; 6:100431. [PMID: 36636725 PMCID: PMC9829696 DOI: 10.1016/j.crfs.2022.100431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/21/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022] Open
Abstract
Food processing conditions affect the accurate detection of gluten by ELISA, which is of importance for proper gluten-free labelling. We prepared different wheat flour-based and incurred baked goods (bread, crispbread, pretzel) to investigate the influence of baking conditions and alkali treatment on gluten quantitation by ELISA using different extraction solvents. Protein composition and extractability were determined (SDS-PAGE, RP-HPLC, GP-HPLC). The extraction solvents showed different performances; none of them could compensate the effect of baking on the detection. Dough preparation, baking and additional alkali treatment decreased protein extractability under reducing and non-reducing conditions. High temperature combined with alkali treatment resulted in the lowest protein extractabilities (<77% for bread crust, <61% for pretzel crust) due to the formation of disulfide and non-disulfide gluten crosslinks. There was no clear correlation between the protein composition and the extractability of alcohol- and SDS-soluble proteins of the baked goods. Thus, this research shows that gluten extractability rather than gluten composition is crucial for detection by ELISA in baked goods.
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Affiliation(s)
- Tanja Miriam Schirmer
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
| | - Katharina Anne Scherf
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany,Department of Bioactive and Functional Food Chemistry, Institute of Applied Biosciences, Karlsruhe Institute of Technology (KIT), Adenauerring 20 a, 76131, Karlsruhe, Germany,Corresponding author. Karlsruhe Institute of Technology (KIT), Adenauerring 20 a, 76131, Karlsruhe, Germany. https://bioactivefc.iab.kit.edu
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A Highly Sensitive Method for the Detection of Hydrolyzed Gluten in Beer Samples Using LFIA. Foods 2022; 12:foods12010160. [PMID: 36613374 PMCID: PMC9818069 DOI: 10.3390/foods12010160] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/29/2022] Open
Abstract
Most gluten analysis methods have been developed to detect intact gluten, but they have shown limitations in certain foods and beverages in which gluten proteins are hydrolyzed. Methods based on G12/A1 moAbs detect the sequences of gluten immunogenic peptides (GIP), which are the main contributors to the immune response of celiac disease (CD). Immunogenic sequences with tandem epitopes for G12/A1 have been found in beers with <20 mg/kg gluten, which could be consumed by CD patients according to the Codex Alimentarius. Therefore, an accurate method for the estimation of the immunogenicity of a beer is to use two moAbs that can recognize celiac T cell epitopes comprising most of the immunogenic response. Here, a specific and sensitive method based on G12/A1 LFIA was developed to detect GIP in beers labeled gluten-free or with low gluten content, with an LOD of 0.5 mg/kg. A total of 107 beers were analyzed, of those 6.5% showed levels higher than 20 mg/kg gluten and 29% showed levels above the LOD. In addition, G12/A1 LFIA detected gluten in 15 more beer samples than competitive ELISA with another antibody. Despite their labeling, these beers contained GIP which may cause symptoms and/or intestinal damage in CD patients.
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Sajid Mushtaq B, Zhang W, Al-Ansi W, Ul Haq F, Rehman A, Omer R, Mahmood Khan I, Niazi S, Ahmad A, Ali Mahdi A, Al-Maqtari QA, Walayat N, Wang L. A Critical Review on the Development, Physicochemical Variations and Technical Concerns of Gluten Free Extrudates in Food Systems. FOOD REVIEWS INTERNATIONAL 2021. [DOI: 10.1080/87559129.2021.1976793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Bilal Sajid Mushtaq
- School of Food Science and Technology, State Key Laboratory of Food Science and Technology, National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China
| | - Wenhui Zhang
- Institute of Food Science, Tibet Academy of Agriculture and Animal Husbandry Sciences, Lhasa, Tibet, China
| | - Waleed Al-Ansi
- School of Food Science and Technology, State Key Laboratory of Food Science and Technology, National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China
| | - Faizan Ul Haq
- School of Food Science and Technology, State Key Laboratory of Food Science and Technology, National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China
| | - Abdur Rehman
- School of Food Science and Technology, State Key Laboratory of Food Science and Technology, National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China
| | - Rabia Omer
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Imran Mahmood Khan
- School of Food Science and Technology, State Key Laboratory of Food Science and Technology, National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China
| | - Sobia Niazi
- School of Food Science and Technology, State Key Laboratory of Food Science and Technology, National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China
| | - Aqsa Ahmad
- School of Biotechnology, Jiangnan University, Wuxi, China
| | - Amer Ali Mahdi
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China
| | - Qais Ali Al-Maqtari
- School of Food Science and Technology, State Key Laboratory of Food Science and Technology, National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China
| | - Noman Walayat
- Department of Food Science and Engineering, College of Ocean, Zhejiang University of Technology, Hangzhou, China
| | - Li Wang
- School of Food Science and Technology, State Key Laboratory of Food Science and Technology, National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China
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Ribeiro M, de Sousa T, Sabença C, Poeta P, Bagulho AS, Igrejas G. Advances in quantification and analysis of the celiac-related immunogenic potential of gluten. Compr Rev Food Sci Food Saf 2021; 20:4278-4298. [PMID: 34402581 DOI: 10.1111/1541-4337.12828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 05/18/2021] [Accepted: 07/21/2021] [Indexed: 12/21/2022]
Abstract
Gluten-free products have emerged in response to the increasing prevalence of gluten-related disorders, namely celiac disease. Therefore, the quantification of gluten in products intended for consumption by individuals who may suffer from these pathologies must be accurate and reproducible, in a way that allows their proper labeling and protects the health of consumers. Immunochemical methods have been the methods of choice for quantifying gluten, and several kits are commercially available. Nevertheless, they still face problems such as the initial extraction of gluten in complex matrices or the use of a standardized reference material to validate the results. Lately, other methodologies relying mostly on mass spectrometry-based techniques have been explored, and that may allow, in addition to quantitative analysis, the characterizationof gluten proteins. On the other hand, although the level of 20 mg/kg of gluten detected by these methods is sufficient for a product to be considered gluten-free, its immunogenic potential for celiac patients has not been clinically validated. In this sense, in vitro and in vivo models, such as the organoid technology applied in gut-on-chip devices and the transgenic humanized mouse models, respectively, are being developed for investigating both the gluten-induced pathogenesis and the treatment of celiac disease. Due to the ubiquitous nature of gluten in the food industry, as well as the increased prevalence of gluten-related disorders, here we intend to summarize the available methods for gluten quantification in food matrices and for the evaluation of its immunogenic potential concerning the development of novel therapies for celiac disease to highlight active research and discuss knowledge gaps and current challenges in this field.
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Affiliation(s)
- Miguel Ribeiro
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,Functional Genomics and Proteomics Unity, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,LAQV-REQUIMTE, Faculty of Science and Technology, University Nova of Lisbon, Caparica, Lisbon, Portugal
| | - Telma de Sousa
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,Functional Genomics and Proteomics Unity, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,LAQV-REQUIMTE, Faculty of Science and Technology, University Nova of Lisbon, Caparica, Lisbon, Portugal
| | - Carolina Sabença
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,Functional Genomics and Proteomics Unity, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,LAQV-REQUIMTE, Faculty of Science and Technology, University Nova of Lisbon, Caparica, Lisbon, Portugal
| | - Patrícia Poeta
- LAQV-REQUIMTE, Faculty of Science and Technology, University Nova of Lisbon, Caparica, Lisbon, Portugal.,Microbiology and Antibiotic Resistance Team (MicroART), Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
| | - Ana Sofia Bagulho
- National Institute for Agrarian and Veterinarian Research, Elvas, Portugal
| | - Gilberto Igrejas
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,Functional Genomics and Proteomics Unity, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,LAQV-REQUIMTE, Faculty of Science and Technology, University Nova of Lisbon, Caparica, Lisbon, Portugal
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Food Safety and Cross-Contamination of Gluten-Free Products: A Narrative Review. Nutrients 2021; 13:nu13072244. [PMID: 34210037 PMCID: PMC8308338 DOI: 10.3390/nu13072244] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/23/2021] [Accepted: 06/26/2021] [Indexed: 02/06/2023] Open
Abstract
A gluten-free diet (GFD) is currently the only effective treatment for celiac disease (CD); an individual’s daily intake of gluten should not exceed 10 mg. However, it is difficult to maintain a strict oral diet for life and at least one-third of patients with CD are exposed to gluten, despite their best efforts at dietary modifications. It has been demonstrated that both natural and certified gluten-free foods can be heavily contaminated with gluten well above the commonly accepted threshold of 20 mg/kg. Moreover, meals from food services such as restaurants, workplaces, and schools remain a significant risk for inadvertent gluten exposure. Other possible sources of gluten are non-certified oat products, numerous composite foods, medications, and cosmetics that unexpectedly contain “hidden” vital gluten, a proteinaceous by-product of wheat starch production. A number of immunochemical assays are commercially available worldwide to detect gluten. Each method has specific features, such as format, sample extraction buffers, extraction time and temperature, characteristics of the antibodies, recognition epitope, and the reference material used for calibration. Due to these differences and a lack of official reference material, the results of gluten quantitation may deviate systematically. In conclusion, incorrect gluten quantitation, improper product labeling, and poor consumer awareness, which results in the inadvertent intake of relatively high amounts of gluten, can be factors that compromise the health of patients with CD.
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