Titolo della tesi: Food and balms: combined botanical and chemical studies from funerary and domestic contexts
This study examines plant material preserved in the various archaeological contexts incorporating different approaches, including the study of micro- and macroremains as well as chemical profiles. Identification of microremains – pollen grains, phytoliths, NPPs (non-pollen palynomorphs) and plant tissues – and plant macroremains, like seeds and wood, can be achieved with the aid of microscopy, and depends on plant morphology and taxonomy. Residue analysis, performed on amorphous material, relies on the concept of biomarkers, i.e. organic molecules that can be used as the chemical fingerprinting indicating the origin of the substance.
Combining these approaches, the studied material was selected in accordance with state of preservation and availability. It is important to assure that the artefacts studied are minimally affected by the analytical procedure so they can be used for future research or displayed in exhibitions. Samples were prepared in accordance with the optimum instrumental methods and then studied under light microscope, stereomicroscope, and scanning electron microscope (SEM), depending on specific demands of the material. This methodology enabled the morphological study and identification of plant remains. For chemical analysis, visible organic residue was subjected to non-destructive attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FT-IR) and minimally destructive pyrolysis gas chromatography mass spectrometry (Py-GC/MS). Organic residues from pottery vessels, identified as carriers for food offerings, were characterized by gas chromatography mass spectrometry (GC/MS). When relevant, the inorganic fraction of the samples was characterized by scanning electron microscope coupled with energy dispersive X-ray spectrometry (SEM-EDS) and X-ray diffraction (XRD). Selection of the appropriate techniques was modified to suit the demands of each case study. All the acquired data was framed in the context of past archaeological and environmental conditions, as well as available natural materials, allowing a comprehensive interpretation of the archeological plant remains.
The results obtained from Prehistoric funerary sites, mostly based on chemical evidence, revealed that plants and plant products were integral part of burial and ritual practices of Prehistoric communities, even if the plant remains cannot be detected with a naked eye. In particular, clear evidence of beeswax indicates that populations in the Iberian Peninsula actively participated in the widespread exploitation of honeybee products by agrarian communities already between the end of 4th and the beginning of the 3rd millennium BC. Besides, exploitation of oil rich plants to obtain substantial amounts of oil has been documented in the burial ritual of Neolithic/Chalcolithic age in Portugal.
The results obtained from domestic contexts reflect everyday life – plant food selection, storage, and dietary choices. Archaeobotanical materials recovered from pottery vessels originating from now submerged Iron Age site of Gran Carro, located in Central Italy on the shore of Bolsena Lake gave insights into the cereal consumption, crop selection and food preferences, with cultivation of millets complementing more productive crops of wheat and barley. These results add a new perspective to the ever-growing mosaic of knowledge concerning millet cultivation and dispersal in Southern Europe. Carpological remains found in silos of Medieval Lisbon attest to importance and incorporation of fruits, during the changing times, when Muslim and Cristian traditions in direct contact, encouraged further agricultural development. Chemical analysis of organic material carbonized after the Great Lisbon Earthquake allowed the interpretation as an accumulate human waste and provided information about dietary habits and hygienic practices in the 18th century urban setting.
Throughout this thesis, versatile knowledge from social sciences and humanities was combined with that of natural sciences, adopting a transdisciplinary approach in the framework of Archaeometry and Cultural Heritage sciences and using theories, methods, practices and interpretations from different complementary research fields.