Determination of bioactive and potentially toxic compounds in food: raw material analysis and shelf life evaluation

"Bioactive compounds" are extranutritional constituents that typically occur in small quantities in food. They are being intensively studied to evaluate their effects on health. Bioactive compounds include both water soluble compounds, such as phenolics, and lipidic substances such as n-3 fatty acids, tocopherols and sterols. Phenolic compounds, tocopherols and sterols are present in all plants and have been studied extensively in cereals, nuts and oil. n-3 fatty acids are present in fish and all around the vegetable kingdom. The aim of the present work was the determination of bioactive and potentially toxic compounds in cereal based foods and nuts. The first section of this study was focused on the determination of bioactive compounds in cereals. Because of that the different forms of phytosterols were investigated in hexaploid and tetraploid wheats. Hexaploid cultivars were the best source of esterified sterols (40.7% and 37.3% of total sterols for Triticum aestivum and Triticum spelta, respectively). Significant amounts of free sterols (65.5% and 60.7% of total sterols for Triticum durum and Triticum dicoccon, respectively) were found in the tetraploid cultivars. Then, free and bound phenolic compounds were identified in barley flours. HPLCESI/ MSD analysis in negative and positive ion mode established that barley free flavan-3- ols and proanthocyanidins were four dimers and four trimers having (epi)catechin and/or (epi)gallocatechin (C and/or GC) subunits. Hydroxycinnamic acids and their derivatives were the main bound phenols in barley flours. The results obtained demonstrated that barley flours were rich in phenolic compounds that showed high antioxidant activity. The study also examined the relationships between phenolic compounds and lipid oxidation of bakery. To this purpose, the investigated barley flours were used in the bakery production. The formulated oven products presented an interesting content of phenolic compounds, but they were not able to contain the lipid oxidation. Furthermore, the influence of conventional packaging on lipid oxidation of pasta was evaluated in n-3 enriched spaghetti and egg spaghetti. The results proved that conventional packaging was not appropriated to preserve pasta from lipid oxidation; in fact, pasta that was exposed to light showed a high content of potentially toxic compounds derived from lipid oxidation (such as peroxide, oxidized fatty acids and COPs). In the second section, the content of sterols, phenolic compounds, n-3 fatty acids and tocopherols in walnuts were reported. Rapid analytical techniques were used to analyze the lipid fraction and to characterize phenolic compounds in walnuts. Total lipid chromatogram was used for the simultaneous determination of the profile of sterols and tocopherols. Linoleic and linolenic acids were the most representative n-6 and n-3 essential dietary fatty acids present in these nuts. Walnuts contained substantial amounts of γ- and δ-tocopherol, which explained their antioxidant properties. Sitosterol, Δ5-avenasterol and campesterol were the major free sterols found. Capillary electrophoresis coupled to DAD and microTOF was utilized to determine phenolic content of walnut. A new compound in walnut ((2E,4E)- 8-hydroxy-2,7-dimethyl-2,4-decadiene-1,10-dioic acid 6-O-β-D-glucopiranosyl ester, [M−H]− 403.161m/z) with a structure similar to glansreginins was also identified. Phenolic compounds corresponded to 14–28% of total polar compounds quantified. Aglycone and glycosylated ellagic acid represented the principal components and account for 64–75% of total phenols in walnuts. However, the sum of glansreginins A, B and ((2E,4E)-8-hydroxy- 2,7-dimethyl-2,4-decadiene-1,10-dioic acid 6-O-β-D-glucopiranosyl ester was in the range of 72–86% of total quantified compounds.

Multi-pollutants impact on modern cement built heritage

It is well known that the deposition of gaseous pollutants and aerosols plays a major role in causing the deterioration of monuments and built cultural heritage in European cities. Despite of many studies dedicated to the environmental damage of cultural heritage, in case of cement mortars, commonly used in the 20th century architecture, the deterioration due to air multipollutants impact, especially the formation of black crusts, is still not well explored making this issue a challenging area of research. This work centers on cement mortars – environment interactions, focusing on the diagnosis of the damage on the modern built heritage due to air multi-pollutants. For this purpose three sites, exposed to different urban areas in Europe, were selected for sampling and subsequent laboratory analyses: Centennial Hall, Wroclaw (Poland), Chiesa dell'Autostrada del Sole, Florence (Italy), Casa Galleria Vichi, Florence (Italy). The sampling sessions were performed taking into account the height from the ground level and protection from rain run off (sheltered, partly sheltered and exposed areas). The complete characterization of collected damage layer and underlying materials was performed using a range of analytical techniques: optical and scanning electron microscopy, X ray diffractometry, differential and gravimetric thermal analysis, ion chromatography, flash combustion/gas chromatographic analysis, inductively coupled plasma-optical emission spectrometer. The data were elaborated using statistical methods (i.e. principal components analyses) and enrichment factor for cement mortars was calculated for the first time. The results obtained from the experimental activity performed on the damage layers indicate that gypsum, due to the deposition of atmospheric sulphur compounds, is the main damage product at surfaces sheltered from rain run-off at Centennial Hall and Casa Galleria Vichi. By contrast, gypsum has not been identified in the samples collected at Chiesa dell'Autostrada del Sole. This is connected to the restoration works, particularly surface cleaning, regularly performed for the maintenance of the building. Moreover, the results obtained demonstrated the correlation between the location of the building and the composition of the damage layer: Centennial Hall is mainly undergoing to the impact of pollutants emitted from the close coal power stations, whilst Casa Galleria Vichi is principally affected by pollutants from vehicular exhaust in front of the building.

Studio di popolazione sull'associazione tra sindrome delle gambe senza riposo ed emicrania

Introduzione: La sindrome delle gambe senza riposo (RLS) è un disturbo caratterizzato da sensazione spiacevole disestesica generalmente agli arti inferiori, che si presenta o peggiora nelle ore serali-notturne e che migliora con il movimento. Studi clinici hanno mostrato una maggiore prevalenza di RLS negli emicranici, mentre mancano studi condotti su popolazione generale non selezionata. Lo scopo di questo studio era quello di valutare la associazione tra emicrania e RLS in una popolazione italiana adulta. Inoltre è stata valutata l’associazione tra RLS e cefalea fenotipizzata attraverso metodica di principal components analysis (PCA). Materiali e metodi: la presenza di RLS e di emicrania è stata determinata attraverso questionari basati sui criteri diagnostici correnti in un campione di 1567 partecipanti di un fase preliminare di uno studio in corso sulla popolazione adulta della Val Venosta (BZ). Risultati: gli emicranici hanno presentato un significativo maggior rischio di soffrire di RLS rispetto ai non emicranici, anche dopo aggiustamento per fattori confondenti come età, sesso, depressione, ansia e qualità del sonno (p = 0.049). Questa associazione non era modificata dalla presenza di aura emicranica, di cause possibili di RLS secondaria e dalla frequenza di attacchi emicranici. Inoltre la RLS non era risultata significativamente associata alla cefalea di tipo tensivo (TTH). Dall’analisi di associazione tra RLS e cefalea fenotipizzata attraverso PCA era emerso che la componente 1, caratterizzata da sintomi di sensitivizzazione del sistema nervoso centrale (SNC), correlava significativamente con la presenza di RLS (p = 0.021). Conclusioni: RLS ed emicrania sono risultate associate nel nostro campione di popolazione adulta; inoltre la RLS ha mostrato una correlazione significativa con i sintomi di sensitivizzazione del SNC legati agli attacchi di cefalea. Questa associazione potrebbe risiedere in una possibile base patogenetica comune.

Development of methodologies for fish freshness assessment using metabonomics applications.

This study focuses on the use of metabonomics applications in measuring fish freshness in various biological species and in evaluating how they are stored. This metabonomic approach is innovative and is based upon molecular profiling through nuclear magnetic resonance (NMR). On one hand, the aim is to ascertain if a type of fish has maintained, within certain limits, its sensory and nutritional characteristics after being caught; and on the second, the research observes the alterations in the product’s composition. The spectroscopic data obtained through experimental nuclear magnetic resonance, 1H-NMR, of the molecular profiles of the fish extracts are compared with those obtained on the same samples through analytical and conventional methods now in practice. These second methods are used to obtain chemical indices of freshness through biochemical and microbial degradation of the proteic nitrogen compounds and not (trimethylamine, N-(CH3)3, nucleotides, amino acids, etc.). At a later time, a principal components analysis (PCA) and a linear discriminant analysis (PLS-DA) are performed through a metabonomic approach to condense the temporal evolution of freshness into a single parameter. In particular, the first principal component (PC1) under both storage conditions (4 °C and 0 °C) represents the component together with the molecular composition of the samples (through 1H-NMR spectrum) evolving during storage with a very high variance. The results of this study give scientific evidence supporting the objective elements evaluating the freshness of fish products showing those which can be labeled “fresh fish.”

A journey through the capital structure of the banking sector: Empirical evidence for Europe from 2008 to 2012

Systemic risk is the protagonist of the recent financial crisis. This thesis proposes a definition and a propagation mechanism for systemic risk. Risk management has a direct linkage with capital management, when addressing the question that the risk handled by a financial institution is compatible with the amount of equity available. This thesis proposes a risk management of liquid market variables, which compose the assets of a bank, based on the statistical tool of PCA. The principal component analysis will define the PCR, or Principal Components of Risk. Such definition of Risk will be adopted to test if the risk represented by PCR is explanatory of the movements of equity and/or debt for the banks included in the in the index Itraxx financial senior: the results of these regressions will be compared with a formal Capital Adequacy test in order to assess the financial soundness of the main financial European institutions.

Study of the components of quality in SO2-free wines obtained by innovative vinification protocols. Evaluation of the pre-fermentative addition of lysozyme and oenological tannins.

The research performed during the PhD candidature was intended to evaluate the quality of white wines, as a function of the reduction in SO2 use during the first steps of the winemaking process. In order to investigate the mechanism and intensity of interactions occurring between lysozyme and the principal macro-components of musts and wines, a series of experiments on model wine solutions were undertaken, focusing attention on the polyphenols, SO2, oenological tannins, pectines, ethanol, and sugar components. In the second part of this research program, a series of conventional sulphite added vinifications were compared to vinifications in which sulphur dioxide was replaced by lysozyme and consequently define potential winemaking protocols suitable for the production of SO2-free wines. To reach the final goal, the technological performance of two selected yeast strains with a low aptitude to produce SO2 during fermentation were also evaluated. The data obtained suggested that the addition of lysozyme and oenological tannins during the alcoholic fermentation could represent a promising alternative to the use of sulphur dioxide and a reliable starting point for the production of SO2-free wines. The different vinification protocols studied influenced the composition of the volatile profile in wines at the end of the alcoholic fermentation, especially with regards to alcohols and ethyl esters also a consequence of the yeast’s response to the presence or absence of sulphites during fermentation, contributing in different ways to the sensory profiles of wines. In fact, the aminoacids analysis showed that lysozyme can affect the consumption of nitrogen as a function of the yeast strain used in fermentation. During the bottle storage, the evolution of volatile compounds is affected by the presence of SO2 and oenological tannins, confirming their positive role in scaveging oxygen and maintaining the amounts of esters over certain levels, avoiding a decline in the wine’s quality. Even though a natural decrease was found on phenolic profiles due to oxidation effects caused by the presence of oxygen dissolved in the medium during the storage period, the presence of SO2 together with tannins contrasted the decay of phenolic content at the end of the fermentation. Tannins also showed a central role in preserving the polyphenolic profile of wines during the storage period, confirming their antioxidant property, acting as reductants. Our study focused on the fundamental chemistry relevant to the oxidative phenolic spoilage of white wines has demonstrated the suitability of glutathione to inhibit the production of yellow xanthylium cation pigments generated from flavanols and glyoxylic acid at the concentration that it typically exists in wine. The ability of glutathione to bind glyoxylic acid rather than acetaldehyde may enable glutathione to be used as a ‘switch’ for glyoxylic acid-induced polymerisation mechanisms, as opposed to the equivalent acetaldehyde polymerisation, in processes such as microoxidation. Further research is required to assess the ability of glutathione to prevent xanthylium cation production during the in-situ production of glyoxylic acid and in the presence of sulphur dioxide.