Heritage Science: A Future-Oriented Cross-Disciplinary Field.

"Heritage science is the study of interpretation and management of the material evidence of the humankind. It enables both society and individuals to exercise their right to cultural heritage and contributes to our understanding of who we are and our sense of place. Heritage science demonstrates its relevance to, as well as its deep roots in chemistry, and in other physical and engineering sciences …" Read more in the Guest Editorial by Matija Strlič

The response of Monoterpenes to Different Enzyme Preparations in Gewürztraminer (Vitis vinifera L.) Wines

The α-terpineol, linalool, nerol and geraniol, which are the main aromatic monoterpenes in the grapevine varietyGewürztraminer, were determined in the grapes, must and wine after treatment with six different pectolytic enzymes[Lallzyme-β (‘Lall’); Rohavin VR-C (‘VRX’), Rohapect D5L (‘D5L’), Rohavin MX (‘MX’), Rohapect VRC (‘VRC’),Endozym cultivar A (‘Cult. A’)], and after treatment with β-glucosidase (βG, EC 3.2.1.21). The concentrations ofmonoterpenic compounds were determined by solid-phase microextraction (SPME) and GC-MS. The most abundantmonoterpene in the grapes of Gewürztraminer was geraniol (66.7 μg/L), followed by nerol (13.3 μg/L), α-terpineol(7.8 μg/L) and finally linalool (3.3 μg/L). Gewürztraminer wine from must treated with the Lall enzyme preparationwas the most aromatic, which was also confirmed by chemical and sensory analysis in which the concentrations ofnerol (45.9 μg/L), geraniol (31.8 μg/L), α-terpineol (10.5 μg/L) and linalool (6.1 μg/L) were determined. The winesproduced from must treated chemically with enzymes showed higher concentrations of many of the monoterpenecompounds compared to the control, although the sensorial analysis did not affirm this convincingly

Autoxidation of lipids in parchment

Historic parchment is a macromolecular material, which is complex due to its natural origin, inhomogeneity of the skin structure, unknown environmental history and potential localised degradation. Most research into its stability has so far focussed on thermal and structural methods of analyses. Using gas chromatographic analysis of the atmosphere surrounding parchment during oxidation, we provide the experimental evidence on the production of volatile aldehydes, which can be the products of lipid autoxidation. Oxidation of parchment with different aldehyde emissions was additionally followed in situ using chemiluminometry and the same techniques were used to evaluate the oxidation of differently delipidised parchment. It was shown that the production of peroxides and the emission of aldehydes from the material decrease with lower lipid content. Building on this evidence, we can conclude that the presence of lipids (either initially present in the skin or resulting from conservation intervention) leads to oxidative degradation of collagen and that the non-destructive analysis of the emission of volatiles could be used as a quick tool for evaluation of parchment stability

Emission of reactive oxygen species during degradation of iron gall ink

Iron gall inks are characterised by high contents of acids and transition metals, promoting degradation of cellulose due to hydrolysis and oxidation, respectively. Their chemical interaction with the environment is not well understood, especially in view of emissions of degradation products which could lead to spread of degradation processes. In order to study the emissions, we employed gas chromatography/mass spectrometry following headspace micro-extraction, and liquid chromatography following hydroxyl radical scavenging with appropriate probes. We also studied chemiluminescence of cellulose affected by ink degradation. We show that while the emissions of organic volatile degradation compounds by inks are less intense than those of surrounding paper, ink does promote the degradation of cellulose across big distances (from object to object). We were able to link this to emission of reactive oxygen species, probably hydrogen peroxide. Its emission from ink is considerably more intensive than from paper

Determination of mechanical properties of historical paper based on NIR spectroscopy and chemometrics - a new instrument

Due to sampling restrictions in the analysis of cultural heritage materials, non-destructive approaches are intensively sought for. While NIR spectrometry has rarely been used for this purpose due to the complexity of the spectra, chemometric methods can be used to extract the necessary information. For the purpose of determination of mechanical properties of historical paper, partial least squares approach was used and it is shown that tensile strength, and tensile strength after folding, can be estimated based on NIR spectra. As the mechanical properties of paper-based objects define their accessibility, a new dispersive portable instrument was built, which will enable us to rapidly survey the condition of library and archival collections

From Smelly Buildings to the Scented Past: An Overview of Olfactory Heritage

Olfactory heritage is an aspect of cultural heritage concerning the smells that are meaningful to a community due to their connections with significant places, practices, objects or traditions. Knowledge in this field is produced at the intersection of history, heritage science, chemistry, archaeology, anthropology, art history, sensory science, olfactory museology, sensory geography and other domains. Drawing on perspectives from system dynamics, an approach which focuses on how parts of a system and their relationships result in the collective behaviours of the system, we will outline a series of practices relevant to this field and identify the elements, materials and competences involved, as well as the connections and interactions. While research in olfactory heritage is currently growing, much of the knowledge that could advance our understanding of this field is still being developed within disciplinary boundaries, leading to little integration of the knowledge and methods and limited interdisciplinary interpretation of findings. In the first part, we review the methodologies for identifying, researching and preserving olfactory heritage, highlighting methodological opportunities and challenges from diverse perspectives like smellscape research, odour nuisance management or heritage science. In the second part, we review the presentation and communication of olfactory heritage in museums and other heritage spaces, outlining the value of presenting scents to wide audiences for interpretation and engagement purposes. Finally, we discuss challenges associated with historical scent reconstruction, and discuss future directions for the field, such as the potential of mining large digital collections for olfactory data

Spectral sensitivity of the discoloration of Historical rag paper

This paper discusses the spectral sensitivity of the discoloration of historical rag paper simultaneously affected by Relative Humidity (RH) and Oxygen concentration [O2] in the ambient environment. Sacrificial samples were degraded using narrowband radiation sources centred at 450 nm, 525 nm, and 625 nm in combinations of RH and [O2] at two levels: 0% [O2] and 70% RH, 21% [O2] and 70% RH, 0% [O2] and 20% RH, and 21% [O2] and 20% RH. Diffuse reflectance was measured before and during the degradation experimental runs. Consistent qualitative results were obtained for the change in reflectance and the change in tristimulus total color change in CIELAB color space. In both cases, the increase of discoloration was modelled logarithmically over time. Among the three factors investigated in this research, wavelength of the radiation (Λ) was found to have the strongest effect. The radiation at 450 nm induced the most and fastest discoloration whereas the radiation at 625 nm induced the least and slowest discoloration. This spectral dependence was likely to be related to the photo energies at different wavelengths, but other factors were found to have played a role. Further analyses revealed that the main effects and the effects of the interactions between [O2] and Λ and between RH and Λ on the discoloration of historical rag paper were statistically significant. It suggests that managing the spectral power distribution of the radiation source can be crucial in the collection management

Systematic evaluation of 1,2-dichloropropane emissions from do-it-yourself spray foam insulation products

Previous studies found 1,2-dichloropropane (1,2-DCP) emitted from spray foam insulation (SPF) products and it was hypothesised that 1,2-DCP is emitted from cured SPF due to thermal degradation of flame retardants. This study experimentally tested this hypothesis using qualitative and quantitative gas-chromatography-mass-spectrometry (GC-MS) of 1,2-DCP in thirteen SPF products. Multiple batches of each product were tested and 1,2-DCP was found in all samples: raw material (n = 1), emitted during application and curing (n = 12) and emitted from cured products (n = 3). The flame retardants previously hypothesised as the source of 1,2-DCP were spiked onto Tenax-TA tubes and analysed, but no 1,2-DCP was detected. Our experimental data needs a new hypothesis to fully explain the presence of 1,2-DCP. We hypothesise that 1,2-DCP could be present in raw materials used in industrial processing or potentially enter as an impurity resulting from the production process of SPF materials. Our results provide the first experimental evidence of 1,2-DCP emissions during application of do-it-yourself SPF products. 1,2-dichloropropane was classified as a Class 1 carcinogen in 2014, however most occupational exposure limits were developed prior to the re-classification. Further research focusing on health risks is recommended to evaluate optimal balance between energy conservation, chemical exposure, ventilation strategies and materials selection

Kinetics of accelerated degradation of historic iron gall ink-containing paper

Although degradation of iron gall ink containing paper has been scientifically studied for almost 250 years, we still do not have a good understanding of the kinetics of the process. While many studies focussed on model samples to avoid the inhomogeneity of real historic samples or the need for sampling, this research was conducted on a selection of real documents. Accelerated degradation experiments were performed at six combinations of temperature and relative humidity (RH) in the intervals 50–80 °C/20–80% RH. The analytical methods were optimised such that sample consumption was minimised and errors and uncertainties were evaluated. The results show that the rate of degradation, measured as change in the degree of polymerisation of cellulose in paper beneath ink, can be described in Arrhenius terms, and that the apparent activation energy for the process depends on the moisture content in the material. The variation is consistent with the process of hydrolysis becoming less prominent at lower moisture content values, although the results indicate that hydrolytic degradation predominates during natural ink-induced degradation. In the context of the historic samples used in the study, the presence of ink accelerated the degradation of paper by a constant factor of 1.59 in comparison to paper without ink, across the range of experimental T and RH. This indicates that a dose-response function could be developed for ink-induced degradation of paper

Quantitative NIR spectroscopy for determination of degree of polymerisation of historical paper

This paper discusses the development of a near infrared (NIR) spectroscopic method coupled with multivariate analysis to characterise historical paper. Specifically, partial least squares (PLS) regression was used to predict one of the most important properties of paper as a condition indicator – degree of polymerisation (DP). Supported by a set of model cellulose samples, the NIR-PLS method for DP prediction was validated and the modelling approach that led to the best prediction of DP of paper was established. The coefficient of variation of the NIR-PLS models were found to be approximately 8% and 20% of the DP of model cellulose and historical paper, respectively. The variance of the reference DP, the variance of the predicted DP, and the model bias were identified as the main sources of the total expected generalisation error of prediction. For both model cellulose and historical paper, the variance of the predicted DP by the NIR-PLS models contributed the most to the total error of prediction. This suggests that improving the instrumentation and the operation procedure is essential to improve model performance. Furthermore, the effect of water content of the samples on model performance was investigated. The model for historical paper was proven to be robust to relative humidity fluctuations between 30% and 70%, indicating the applicability of the model for collection surveys in a range of environments