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

Morpho-chemical characterization of individual ancient starches retrieved on ground stone tools from Palaeolithic sites in the Pontic steppe

Despite the extensive literature on the retrieval of digestible starches from archaeological contexts, there are still significant concerns regarding their genuine origin and durability. Here, we propose a multi-analytical strategy to identify the authenticity of ancient starches retrieved from macrolithic tools excavated at Upper Paleolithic sites in the Pontic steppe. This strategy integrates the morphological discrimination of starches through optical microscopy and scanning electron microscopy with single starch chemo-profiling using Fourier transform infrared imaging and microscopy. We obtained evidence of aging and biomineralization in the use-related starches from Palaeolithic sites, providing a methodology to establish their ancient origin, assess their preservation status, and attempt their identification. The pivotal application of this multidisciplinar approach demonstrates that the macrolithic tools, from which starches were dislodged, were used for food-processing across the Pontic Steppe around 40,000 years ago during the earliest colonization of Eurasia by Homo sapiens.

Paleoproteomics

Paleoproteomics, the study of ancient proteins, is a rapidly growing field at the intersection of molecular biology, paleontology, archaeology, paleoecology, and history. Paleoproteomics research leverages the longevity and diversity of proteins to explore fundamental questions about the past. While its origins predate the characterization of DNA, it was only with the advent of soft ionization mass spectrometry that the study of ancient proteins became truly feasible. Technological gains over the past 20 years have allowed increasing opportunities to better understand preservation, degradation, and recovery of the rich bioarchive of ancient proteins found in the archaeological and paleontological records. Growing from a handful of studies in the 1990s on individual highly abundant ancient proteins, paleoproteomics today is an expanding field with diverse applications ranging from the taxonomic identification of highly fragmented bones and shells and the phylogenetic resolution of extinct species to the exploration of past cuisines from dental calculus and pottery food crusts and the characterization of past diseases. More broadly, these studies have opened new doors in understanding past human-animal interactions, the reconstruction of past environments and environmental changes, the expansion of the hominin fossil record through large scale screening of nondiagnostic bone fragments, and the phylogenetic resolution of the vertebrate fossil record. Even with these advances, much of the ancient proteomic record still remains unexplored. Here we provide an overview of the history of the field, a summary of the major methods and applications currently in use, and a critical evaluation of current challenges. We conclude by looking to the future, for which innovative solutions and emerging technology will play an important role in enabling us to access the still unexplored "dark" proteome, allowing for a fuller understanding of the role ancient proteins can play in the interpretation of the past.