In many countries, commercial bread often contains additives to improve flavor, texture, color, shelf life, nutrition, and ease of production. Bread is one of the oldest prepared foods. Evidence from 30,000 years ago in Europe and Australia revealed 3 ingredient buckwheat bread residue on rocks used for pounding plants.
An early leavened bread was baked as early as 6000 BC by the Sumerians, who may have passed on their knowledge to the Egyptians around 3000 BC. The Egyptians refined the process and started adding yeast to the flour. There were multiple sources of leavening available for early bread. Airborne yeasts could be harnessed by leaving uncooked dough exposed to air for some time before cooking. The ancient Egyptians, Greeks, and Romans all considered the degree of refinement in the bakery arts as a sign of civilization.
Gluten-free breads are made using flours from a variety of ingredients such as almonds, rice, sorghum, corn, legumes such as beans, and tubers such as cassava. Since these foods lack gluten, dough made from them may not hold its shape as the loaves rise, and their crumb may be dense with little aeration. In wheat, phenolic compounds are mainly found in hulls in the form of insoluble bound ferulic acid, where it is relevant to wheat resistance to fungal diseases. Rye bread contains phenolic acids and ferulic acid dehydrodimers.
Glutenin and gliadin are functional proteins found in wheat bread that contribute to the structure of bread. Glutenin forms interconnected gluten networks within bread through interchain disulfide bonds. Gliadin binds weakly to the gluten network established by glutenin via intrachain disulfide bonds. Acrylamide is neurotoxic, has adverse effects on male reproduction and developmental toxicity and is carcinogenic. It is most commonly eaten with the hands, either by itself or as a carrier for other foods.