Why an Atheist Thinks the Shroud of Turin is the Real Deal

Maillard Reaction

The other way is through and extraordinarily complex chemical reaction called a Maillard reaction. It takes place when amino acid reacts with sugar. It also produces chemical substances, melanoidins, that have a distinctive brownish or yellowish color similar to melanin.

Maillard reactions are also common in cooking when heat starts the reaction of amino compounds and sugars that are both together in a food. The brown color on toast is because of a Maillard reaction and not carmelization.

Eva Wittgenstein, a medical researcher at the University of Cincinnati discovered that a substance, dihydroxyacetone (DHA), caused darkening appearance on the skin. She had been experimenting with the substance, testing it as a pharmaceutical drug for treating a metabolism defect called Glycogen Storage Disease. The discovery that the drug darkened skin was accidental. In 1960, Coppertone, a manufacturer of protective suntan lotions, introduced Coppertone QT. The QT stood for Quick Tan, and their advertisements touted sunless  tans in three to five hours. It was DHA and it worked extraordinarily well if you wanted to be orange.

DHA, produced from sugar cane was not the only chemical that will react in this way with human amines. Erythrulose, a sugar syrup extracted from raspberries produces similar results but a less orange and more brownish color. Another chemical is Saponaria officinali. This a natural soap extracted from a wild perennial flower called Soapwort and Sweet William.