Hydrochloric acid a hazardous liquid which must be used with care. When used on brickwork the reaction with the mortar only continues until the acid has all been converted, producing calcium chloride, carbon dioxide, and water: Many chemical reactions involving hydrochloric acid are applied in the production of food, food ingredients, and food additives. Typical products include aspartame, fructose, citric acid, lysine, hydrolyzed vegetable protein as food enhancer, and in gelatin production. Food-grade (extra-pure) hydrochloric acid can be applied when needed for the final product. Gastric acid is one of the main secretions of the stomach. It consists mainly of hydrochloric acid
Stomach to other organs, with only some 20 genes being highly specific. The corresponding specific proteins expressed in stomach are mainly involved in creating a suitable environment for handling the digestion of food for uptake of nutrients. Highly stomach-specific proteins include GKN1, expressed in the mucosa; pepsinogen PGC and the lipase LIPF, expressed in chief cells; and gastric ATPase ATP4A and gastric intrinsic factor GIF, expressed in parietal cells. In early human embryogenesis, the ventral part of the embryo abuts the yolk sac. During the second week of development, as the embryo grows, it begins to surround parts of the sac.