Gluten analysis

Wheat, barley and rye are sources of gluten and diverse food products are made from the grains of these cereals. Despite some species-specific differences, the molecular properties of the gluten proteins show similar characteristics in forming a unique protein network that has been extensively described in terms of its subunits and composition, its function in bakery products and its implications for human health.There are many reasons for analysing gluten to serve purposes as diverse as assessing flour quality, selecting and breeding suitable cereal varieties, identifying varieties, identifying the source of gluten in a product, and quantifying gluten in food and drink, especially to protect gluten intolerant consumers.The level of gluten in food and drink deemed to be safe for people with coeliac disease or non-coeliac gluten sensitivity is set in legislations. Various systems are in place worldwide to regulate food labelling and various testing methods are used or are available to quantify gluten, but cross-border standardisation to harmonize the quantification of gluten in food products has yet to be agreed.To analyse gluten, the proteins must be separated from other possibly interfering food components. As it is difficult to solubilize gluten, gluten extraction is a critical part of the process. The level of gluten, the type of food matrix and the available technology impose further limitations and challenges.In this chapter, we describe a strategy to select the most suitable gluten analysis approach according to the purpose, sample type, gluten level and performance characteristics required. The advantages and disadvantages of qualitative and quantitative gluten analysis techniques, such as gel electrophoresis, immunoassays, asymmetric field flow fractionation multi-angle laser light scattering, chromatography and chromatography coupled methods are covered