Ancient bread recipes: Archaeometric data on charred findings

This study examines charred bread-like samples found in several archaeological sites across northern Italy and dating from the Early Bronze Age to the Early Middle Ages, some of which are included amongst the UNESCO World Heritage Sites. The aim is to investigate differences and homogeneities in bread production processes in different eras and cultures. Bread was a staple food in many ancient societies, but has rarely been found amongst the materials that survive in archaeological sites. When it is found, it is usually because the bread was charred by accidental combustion (falling into the oven during baking) or deliberate combustion (for ritual purposes). The literature on the issue is not abundant, but has been growing over the past decade. There is, therefore, room to propose new study methodologies at this time. We studied eight samples of charred bread-like products and we used optical and scanning electron microscopy to identify plant tissue remains attributable to cereal caryopses, partly modified by bread-making processes. Energy dispersive X-ray spectroscopy and, for the first time, infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR) were also used to investigate the composition and preparation methods of the different types of bread-like products. In particular, FTIR-ATR analysis can give indications about the presence of starch, gluten and lignin in the sample under investigation and it can, therefore, be used as a screening to guide subsequent SEM analysis in the search for specific cereal residues in the dough. In some cases, the different techniques used also revealed the presence of minerals such as silicates and carbonates, probably due to grinding residues or poor sample cleaning. During SEM observations, phytoliths, diatoms and framboids were also found in some of the samples

Optimization of Copper Stain Removal from Marble through the Formation of Cu(II) Complexes in Agar Gels

Copper complexes with different ligands (ethylenediaminetetraacetic acid, EDTA, ammonium citrate tribasic, TAC, and alanine, ALA) were studied in aqueous solutions and hydrogels with the aim of setting the optimal conditions for copper stain removal from marble by agar gels, with damage minimization. The stoichiometry and stability of copper complexes were monitored by ultraviolet-visible (UV-Vis) spectroscopy and the symmetry of Cu(II) centers in the different gel formulations was studied by electron paramagnetic resonance (EPR) spectroscopy. Cleaning effectiveness in optimized conditions was verified on marble laboratory specimens through color variations and by determining copper on gels by inductively coupled plasma-mass spectrometry (ICP-MS). Two copper complexes with TAC were identified, one having the known stoichiometry 1:1, and the other 1:2, Cu(TAC)2, never observed before. The stability of all the complexes at different pH was observed to increase with pH. At pH 10.0, the gel\u2019s effectiveness in removing copper salts from marble was the highest in the presence of ALA, followed by EDTA, TAC, and pure agar gel. Limited damage to the marble surface was observed when gels with added EDTA and TAC were employed, whereas agar gel with ALA was determined to be the most efficient and safe cleaning material

Historical silks: a novel method to evaluate their condition with ATR-FTIR spectroscopy and Principal Component Analysis

Understanding the conservation condition of historical silk yarn allows to define appropriate storage, care and display of historical silk collections. This paper discusses the characterisation of silk fabrics from a collection of traditional Japanese samurai armours which date back from the 16th to the 20th century (Morigi Collection, Museo delle Culture, Lugano, Switzerland). An analytical protocol to assess silk fabrics conditions was defined, based on microinvasive ATR-FTIR spectroscopy. In particular, the amide I and II region was studied in order to extrapolate the conformational information about silk proteins. According to literature, this kind of information can be related to different degradation stages. A linear correlation was found between the amide I and the amide II shifts, allowing to assess the silk fibre condition. Along with this bivariate approach based on intensity ratios, a multivariate approach based on Principal Component Analysis was also applied to ATR-FTIR spectra. This allowed to group together silks with the same state of preservation. The findings of this research offer a valuable method to researchers and conservators to identify the most damaged textiles; the differentiation between original and restoration materials was also possible in some cases

Tackling the Challenging Determination of Trace Elements in Ultrapure Silicon Carbide by LA-ICP-MS

The goal of accurately quantifying trace elements in ultrapure silicon carbide (SiC) with a purity target of 5N (99.999% purity) was addressed. The unsuitability of microwave-assisted acid digestion followed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis was proved to depend mainly on the contamination induced by memory effects of PTFE microwave vessels and by the purity levels of acids, even if highly pure ones were used in a clean environment. A new analytical protocol for the direct analysis of the solid material by laser ablation coupled with ICP-MS (LA-ICP-MS) was then exploited. Different samples were studied; the best results were obtained by embedding SiC (powders or grains) in epoxy resin. This technique has the great advantage of avoiding any source of external contamination, as grinding, pressing and sintering pretreatments are totally unnecessary. Two different laser wavelengths (266 and 193 nm) were tested, and best results were obtained with the 266 nm laser. The optimized protocol allows the determination of elements down to the sub-mg/kg level with a good accuracy level

La tavolozza di Francesco Hayez. Riflessioni intorno alla materia dell\u2019arte ottocentesca

Il progetto ha previsto l\u2019analisi di sedici dipinti del sommo pittore del Romanticismo italiano Francesco Hayez, tramite le tecniche non invasive di riflettografia e spettroscopia infrarossa. I risultati principali sono stati la definizione della tavolozza pittorica dell\u2019artista e la redazione di un repertorio commentato sulle ricerche storico-artistiche e archivistiche sui materiali e sulle tecniche della pittura italiana ottocentesca. I contenuti derivanti dalle indagini chimiche e storico-artistiche sono stati tradotti in itinerari formativi ed educativi, anche sperimentando nuove modalit\ue0 comunicative facenti uso di dispositivi tecnologici e con un approccio interdisciplinare ed hands on

INTERNATIONAL JOURNAL OF CONSERVATION SCIENCE ARE COMMERCIAL PIGMENTS RELIABLE REFERENCES FOR THE ANALYSIS OF PAINTINGS?

International audienceWhen paintings are examined by spectroscopic techniques, building a robust database is of major importance, in order to compare the analyses with reliable references and to correctly understand the results. The database, which is usually homemade, should include carefully chosen commercial pigments, which should be as pure as possible and should correspond to the expected formula or composition of the historical pigments. Unfortunately, sometimes no correspondence between the names of the pigments used by companies and the actual composition of some of the colors is ascertained. In some cases, the composition is in fact made up of different chemical compounds; in others the presence of extenders is revealed, for example gypsum and calcite. In this paper some cases studies are discussed, regarding commercial pigments analysed by infrared spectroscopy, thermal analysis, X-ray diffraction and X-ray fluorescence. The results highlighted the importance of checking the purity of commercial pigments and excluding any extraneous compounds while interpreting the results of analytical survey of paintings