A novel route for identifying starch diagenetic products in the archaeological record

PLoS One. 2021 Nov 18;16(11):e0258779. doi: 10.1371/journal.pone.0258779. eCollection 2021.

Abstract

This work introduces a novel analytical chemistry method potentially applicable to the study of archaeological starch residues. The investigation involved the laboratory synthesis of model Maillard reaction mixtures and their analysis through Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS). Thus, starch from sixteen plant species were matured while reacting it with the amino acid glycine. The FTICR-MS analysis revealed > 5,300 molecular compounds, with numerous unique heteroatom rich compound classes, ranging from 20 (Zea mays) to 50 (Sorghum bicolor). These classes were investigated as repositories of chemical structure retaining source and process-specific character, linked back to botanical provenance. We discussed the Maillard reaction products thus generated, a possible pathway for the preservation of degraded starch, while also assessing diagenetic recalcitrance and adsorption potential to mineral surfaces. In some cases, hydrothermal experimentation on starches without glycine reveals that the chemical complexity of the starch itself is sufficient to produce some Maillard reaction products. The article concludes that FTICR-MS offers a new analytical window to characterize starchy residue and its diagenetic products, and is able to recognize taxonomic signals with the potential to persist in fossil contexts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Archaeology / methods
  • Chemistry Techniques, Analytical*
  • Cyclotrons
  • Humans
  • Maillard Reaction
  • Sorghum / chemistry*
  • Spectroscopy, Fourier Transform Infrared
  • Starch / chemistry
  • Starch / isolation & purification*
  • Zea mays / chemistry*

Substances

  • Starch

Grants and funding

This work was made possible by the Canadian Social Sciences and Humanities Research Council under its Partnership Grant Program no. 895-2016-1017 to JM. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.