text: Maillard reaction The Maillard reaction is a form of non-enzymatic browning involving an amino acid and a reducing sugar. The cellulose fibers of the shroud are coated with a thin carbohydrate layer of starch fractions, various sugars, and other impurities. The potential source for amines required for the reaction is a decomposing body, and no signs of decomposition have been found on the Shroud. Rogers also notes that their tests revealed that there were no proteins or bodily fluids on the image areas. Also, the image resolution and the uniform coloration of the linen resolution seem to be incompatible with a mechanism involving diffusion.
  Fringe theories
  Images of coins, flowers and writing
  Various people claim to have detected images of flowers on the shroud as well as coins over the eyes of the face in the image, writing and other objects. However, a study published in 2011 by Lorusso and others subjected two photographs of the shroud to detailed modern digital image processing, one of them being a reproduction of the photographic negative taken by Giuseppe Enrie in 1931. They did not find any images of flowers or coins or writing or any other additional objects on the shroud in either photograph, they noted the faint images were "only visible by incrementing the photographic contrast" so they concluded that these signs might be linked to protuberances in the yarn and possibly also to the alteration and influence of the texture of the Enrie photographic negative during its development in 1931. The use of coins to cover the eyes of the dead is not attested for 1st-century Judea. The existence of the coin images is rejected by most scientists.