Many bread products contain an amino acid known as L-cysteine, which is used as a softening agent. L-cysteine is derived from either human hair or poultry feathers, and it can be found in many ...

The amino acid cysteine has a chemically reactive side chain that can form bonds with another cysteine. Amino acids can also be basic, like lysine, or acidic, like glutamic acid. The sequence and ...