Combined use of elemental profiles and stable isotope ratios for the botanical and commercial discrimination of gum Arabic

Gum arabic (GA) is a natural, edible gum with particular characteristics resulting from its complex mixture of polysaccharides and glycoproteins. GA is used extensively in several fields and global demand is steadily increasing; for this reason, the determination of GA origin is fundamental to counteract commercial frauds and ensure food safety. The purpose of the study was to investigate whether elemental and isotopic profiles could discriminate, first, between GA produced from plants belonging to the same genus (Acacia) but to 2 different species (A. senegal, SN; A. seyal, SY), and, second, considering only GA of the same botanical origin (SN), between gums produced from different geographic areas (Kordofan region in Sudan vs other Sub-Saharan areas) and commercially resulting in products with different characteristics. The Principal Component Analysis (PCA), combining elemental and stable isotope profiles, could clearly separate the 45 gum samples in 2 clusters corresponding to the botanical species of origin. Results were screened using a partial least squares regression (PLS-R) model developed following the leave-one-out cross-validation approach and including a validation subset of 8 samples. All the calibration and validation samples showed a 100% correct classification, both for SN and SY. Furthermore, the PCA, using only the C, N, Cs, Mg and Na content, could adequately discriminate the SN samples according to their geographic origin, distinguishing the Kordofan samples, traditionally renowned as top-quality products, from the generic gum samples produced in other Sub-Saharan areas

Stable isotope ratio analysis for the characterisation of edible insects

Entomophagy, or the act of eating insects, has been practiced since ancient times, but it started to gain more popularity, especially in Western countries, only recently. As sustainability is one of the current emerging themes, the inclusion of insects in our diet is a valid alternative that might help reduce the amount of water and land used for livestock and the associated emissions of greenhouse gasses. Moreover, insects are a source of protein, fibres, vitamins, minerals and fats. Edible insects are considered a novel food, for which no isotopic reference values are yet available. In the present work, samples of farmed edible insects (n=40) belonging to different orders (namely, Coleoptera, Hemiptera, Hymenoptera, Lepidoptera, Odonata and Orthoptera) and insect-based food items (n=4) for human consumption were analysed. The following isotopes, δ13C, δ15N, δ34S, δ18O and δ2H of the defatted samples, together with the δ13C of the fat, were investigated. The aim of the work was to provide the first reference isotopic ratios that can be used for future investigations in the food quality field. The variability of these parameters was dependent on the life stage and diet of insects, their geographical origin, and the addition of ingredients as seasoning

Wear processes in architectural heritage: definition, studies, contrasting measures. The case of UNESCO World Heritage Site “Venice and its Lagoon”

Since 1987 the site “Venice and its Lagoon” is included in the UNESCO World Heritage List and recently adopted its own Management Plan. The Plan doesn't overlay the usual planning tools and techniques, but it's aimed at identifying possible resources for site development and possible threats to the site integrity, and at defining pre-requirement necessary for a better coordination between authorities and institutions responsible for management. One of the finality of the Management Plan is the study of criticalities and potential stress conditions for the urban system, which are able to originate wear processes both physical and perceptual, in the short, medium and long period. The other target is the identification of causes of wear, its dynamics of appearance and development, its influence on protection of monuments and landscape, and the possible contrasting actions. The term “wear” is not only related to process of material decay, but also to process of immaterial one, such as the loss of socio cultural identity, the reduction in the quality of life or the increase of problems in the fruition (or perception) of cultural heritage and urban peculiarities, due to overcrowding or saturations of paths. Analysis related to Venice risk conditions connects wear phenomena to different dynamics, such as: tourism flows, people congestion, progressive conversion of buildings from residential use into services for tourists, widespread of licenses for the so-called plateatici, increasing decay of dockside elements, presence of high water, gradual erosion of canal’s shore due to growing wave motion and pollution, presence of waste, commital of acts of vandalism on built heritage, presence of pigeons or other colonizing animals. Although tourism represents a source of wealth for the city, certainly it can be considered as one of the most critical elements responsible for urban consumption, being an accelerator for all factors connected to wear process and to urban consumption. Since wear dynamics are surely diversified - due to natural or anthropic agents - the identification of effective strategies for controlling those processes and of solutions for mitigating impacts can not be limited to a sectorial approach, but needs to be developed into a wider framework, in which mutual interaction between different phenomena are taken into account. The paper will deeply illustrate the themes above mentioned, referring to the research “Evaluation of wear processes and critical situations in Venice and its Lagoon due to mass tourism and of the relative effect on the site protection: some emblematic cases”, launched by an initiative of the Venice Municipality and under the guidance of the government department responsible for the environment and historical buildings of Venice and its Lagoon (Soprintendenza per i Beni Architettonici e Paesaggistici)