Gluten is a complex of structural proteins naturally found in certain cereal grains, typically referring to the combination of gliadin and glutelin proteins.  

Grains containing gluten include all species of wheat, barley, rye, and some cultivars of oat; moreover, cross hybrids of any of these cereal grains also contain gluten, e.g. triticale. Gluten makes up 75–85% of total protein in bread wheat and it is a key compund in bakery and related technological processes in food industry. 

Histamine is a biogenic amine, a chemical compound formed by the action of microorganisms on amino acids present in foods. High amounts of histamine in food can cause organoleptic alterations as well as trigger undesirable effects once consumed and therefore histamine concentrations should be controlled. Although it is true that there are currently no global regulations, acceptable limits for histamine concentrations in wines are around 10 ppm.