Hydrochloric acid enzyme pepsin by self-cleavage. After leaving the stomach, the hydrochloric acid of the chyme is neutralized in the duodenum by sodium bicarbonate. The stomach itself is protected from the strong acid by the secretion of a thick mucus layer, and by secretin induced buffering with sodium bicarbonate. Heartburn or peptic ulcers can develop when these mechanisms fail. Drugs of the antihistaminic and proton pump inhibitor classes can inhibit the production of acid in the stomach, and antacids are used to neutralize excessive existing acid. Concentrated hydrochloric acid (fuming hydrochloric acid) forms acidic mists. Both the mist and the solution have
Erythorbic acid uptake or clearance from the body was found. A later study found that erythorbic acid is a potent enhancer of nonheme-iron absorption. Since the U.S. Food and Drug Administration banned the use of sulfites as a preservative in foods intended to be eaten fresh (such as salad bar ingredients), the use of erythorbic acid as a food preservative has increased. It is also used as a preservative in cured meats and frozen vegetables. It was first synthesized in 1933 by the German chemists Kurt Maurer and Bruno Schiedt. Erythorbic acid Erythorbic acid (isoascorbic acid, -araboascorbic acid) is a stereoisomer of