contents of the heat treated or not heat treated food item are dissolved although we do not want to associate the composition of the invention with any specific theory the composition of the invention is thought to act by opening the conformation of proteins constituting the gluten especially its toxic fraction and consequently to favour its solubility in the extraction medium indeed during the heat treatment of food products the gluten fractions u03b1 u03b2 and u03b3 gliadines are denatured the disulphide bridges break and consequently insoluble aggregates form that cannot be extracted with 60 ethanol water owing to the combined effect of the components of the composition of the invention i the insoluble aggregate can be extracted with an aqueous ethanol solution 50 70 ethanol water and quantified by elisa and ii the conformation of the gluten molecules increases leaving the antigenic determinants more exposed to the antibodies causing the elisa signal to increase quantitative gluten extraction processes for food items compatible with elisa used for gluten quantification are not known it was surprising that the use of a disulphide bridge reducing agent such as 2 me combined with a dissociating agent such as guanidine hydrochloride permits the gluten content of heat treated and non heat treated food items to be extracted quantitatively see example 2 without adversely affecting their quantification by elisa the results shown in fig1 example 2 clearly indicate that the procedure of the invention is a very suitable tool to use before elisa.