Fingerprinting Starch Degradation Products: Chemical Species of Interest to Ancient Starch Research

Abstract

Molecular degradation of heteroatom rich biopolymers such as polysaccharides is to be expected in archaeological samples, and these must show damage proportional to the taphonomic environment where they belong. The exceptional preservation of native starch granules extensively reported in archaeological sciences remains unexplained. Amino acids and starch react to create complex mixtures of heteroatom-containing products known as melanoidins. Their compounds have a wide range of molecular weights and geochemical species. Some of them are refractory and, if found in archaeological contexts, they could be utilized as proxies of the burial environment and starch precursors. While all the melanoidins show the same basic distribution of heteroatom groups and/or DBE distributions, clear differences among starch taxa do emerge. After the endogenous starch structures and chemistries from native starch granules have been lost to degradation, FTICR-MS is an analytical window to characterize starchy residue. Thus, there is potential for recognizing taxonomic signals in the Maillard reaction degradation products that remain on archaeological residues from stone tools, ceramics, dental calculus, and sediment.