To achieve the above mentioned objectives, a total of 93 micro-samples from 34 different objects, including wooden coffins, cartonnages, and mural paintings, have been obtained from the Egyptian collections of six European and one American museum in order to increase the objects heterogeneity. Collaborations have been personally established with: the museum of mediterranean and near Eastern antiquities (Stockholm, Sweden), the Vatican Museums (Rome, Italy), the Ny Carlsberg Glyptotek (Copenhagen, Denmark), the British Museum (London, UK), the Petrie Museum (London, UK), the Manchester Museum (Manchester, UK) and The Metropolitan Museum of Art (New York, USA). All objects were carefully selected after discussion with curators and conservators and samples were collected by the conservator, or by myself, in correspondence of the areas of interest. This phase required multiple trips to each museum.
All 93 samples have been screened by Fourier transform infrared spectroscopy (FTIR) to investigate the general composition, and a total of 41 samples, the ones showing the possible presence of proteins, have been selected and analyzed by mass spectrometry-based proteomics. Sample preparation included: protein residues extraction, digestion and then analysis of the tryptic peptides by nanoflow liquid chromatography tandem mass spectrometry (nLC-MS/MS). Protein identification was performed with the MaxQuant software. The resulting proteins and their modifications were compared with data from control samples prepared using the same workflow.
Animals such as cattle, domestic pig, horse/donkey and sheep/goat were used to extract collagen and glues show a different nature according to the specific application (e.g. adhesive vs paint binder). In addition the glue was prepared from both bones or soft tissues, it seems again depending on the artistic application. Besides collagens and one case of egg proteins, specific plant seed proteins were unexpectedly identified in two completely unrelated objects. This is the first analytical evidence of the use of seed extracts from two specific plants that were known to be used for other purposes only according to ancient sources. The results demonstrate how palaeoproteomics provides new evidence to advance understanding of the use of specific protein sources which can not be identified with other analytical techniques.
All results have been discussed personally with curators and conservators in order to better correlate the analytical results with what is already known in the Egyptology literature, and a final report for each object have been sent to the museums. In addition the results of the research have been presented at several international conferences:
C. Granzotto et al., ‘Paleoproteomic analysis of binding media and adhesives in ancient Egypt’, oral presentation, Ancient Proteins @20, Copenhagen, August 20th-22nd, 2018.
C. Granzotto et al., ‘Which is the species? Paleoproteomics applied to painted artifacts from ancient Egypt’, oral presentation, EAA, Barcelona, September 5th-8th, 2018.
C. Granzotto et al., ‘Palaeoproteomic analysis of paint binders and adhesives in ancient Egypt’, poster, Gordon Research Conference: Scientific Methods in Cultural Heritage Research, Barcelona, July 22nd-27th, 2018.
C. Granzotto et al., Palaeoproteomic analysis of paint binders and adhesives in ancient Egypt’, poster, ISBA, Jena, September 18th-21st, 2018
I hereby confirm that I have always acknowledged EU funding of my work throughout the fellowship and will continue to do so when presenting or publishing work derived from results from this fellowship in the future.
