|MadSci Network: Biochemistry
Digestion of hair. Hair is composed of proteins [keratins] which have a very highly ordered structure. They have a fibrous character due to their very specific ordering of these proteins forming the cable like structure of hair. Only under very specific conditions such structures can be altered. During a hair treatment to induce curling, the proteins are chemically altered using reducing agents to restructure the proteins but they are not degraded. In order to degrade the hair proteins it is essential to treat them at very acid or alkaline conditions at high temperatures well bove 100C during very long times. Such conditions do not exist in the digestion system of humans. Although the pH is sufficiently low and the enzymes [other proteins] of the stomach are able to digest=hydrolyse to other proteins, these conditions are still too mild for the hydrolysis of hair and they leave the body undigested.
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