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In the present work, Calabrian apple juices belonging to four different cultivars, Royal Gala, Pink Lady, Golden Delicious, and Fuji, were studied. One of the objectives of this work was the characterization of metabolites present in the food matrix and at the same time the possibility of using innovative methodologies based on membrane operations, such as ultrafiltration (UF) and nanofiltration (NF), to obtain from the squeezed apple juice, extracts rich in antioxidants. To improve the overall quality of the study and enhance the coverage of the metabolome two analytical tools were used: NMR and HPLC–UV-ESI–MS/MS. One- and two-dimensional multinuclear NMR spectra combined with chemometric analysis (PCA) were used to identify the metabolic profile of different juice varieties and variations in metabolic composition. On the basis of its higher content of phenolic compounds, the Golden Delicious variety was selected to carry out membrane filtration tests. Specifically, the fresh juice was clarified by UF and then concentrated by NF up to a volume reduction factor (VRF) of 3.3. Permeate and retentate fractions of both processes were analyzed by HPLC–UV and NMR in order to evaluate the membrane selectivity of the selected membranes towards target compounds.

Processing citrus fruits results in significant amount of wastes; however, citrus by-products still contain high amounts of polyphenolic and other bioactive value-added compounds. In addition, bergamot (Citrus bergamia) wastes contain two compounds—brutieridin and melitidin—which exhibit statin-like properties. Recently, novel fermented products containing bioactive compounds received increasing attention because of their health-promoting functions. In this study, the bioconversion of citrus wastes in vinegars with high content in bioactive and aromatic compounds was performed, detecting a high permanence at the end of the process of the main compounds of interest, especially brutieridin and melitidin. In addition, the sensory analysis of the vinegars was performed, obtaining good performances. According to the adopted preselection procedure, 50 out of the 54 strains of acetic acid bacteria were excluded because of their low aptitude to grow in the tested conditions. The best vinegar was produced from citrus wine at pH 2.90 using the Acetobacter aceti strain DSM_3508T as microbial starter. This research has demonstrated—for the first time—the possibility to produce citrus vinegar at high content of brutieridin and melitidin and other bioactive compounds using selected microbial starters.

A new original process has been set-up to obtain hydroxytyrosol-enriched food by means of CO2 supercritical fluid extraction. The process is based on the direct adsorption of hydroxytyrosol on selected foodstuff (e.g., flour, whole-wheat flour, and sugar) when placed in contact with olive oil (which is known to contain this phenol) under controlled temperature and pressure conditions of supercritical CO2. The transfer of the nutraceutical to the foodstuff was initially evaluated using a fortified olive oil model and was then applied to commercial olive oil and foodstuff. The yield of the hydroxytyrosol transfer was demonstrated to be quantitative. In order to prove the suitability of the final products, hydroxytyrosol-enriched flour was used to prepare a bread roll, which maintained the nutraceutical characteristics after the cooking. Finally, DPPH based experiments were performed to prove the radical scavenging activity of the functionalized foodstuff.

A fast method for the determination of methylxanthines in cocoa products and drugs based on PS-MS/MS under MRM condition has been developed. Analyte ions were generated by applying a high voltage on a paper substrate drenched of sample extract using a small volume (∼15 μL) of spray solvent. The gas phase chemistry of the molecules under investigation has been elucidated. The accuracy values of the methodology ranged from 95 to 110%, while the analytical parameters LOQ, LOD, recovery and reproducibility, calculated analyzing spiked samples, confirmed the consistency of the proposed method. Furthermore, real samples have been analyzed both by the developed methodology and by using a classical HPLC-UV approach obtaining comparable values.

Extra virgin olive oil provides an important intake of α-tocopherol, which is part of vitamin E complex. A fast analytical method for its quantification, based on paper spray mass spectrometry, has been developed. The methodology possesses the ability to record mass spectra without sample preparation or preseparation steps. The experiments were performed in Multiple Reaction Monitoring scan mode; in particular, the transitions m/z 429 → m/z 163 for α-tocopherol and m/z 435 → m/z 169 for the labeled internal standard were monitored, in order to obtain the greatest specificity and the best sensitivity. The accuracy of the method was tested analyzing spiked samples prepared at concentrations within the dynamic range of the calibration curve, which returned values near 100%. Furthermore, good values of LOQ and LOD were obtained, demonstrating that this approach can be applied for a rapid screening of tocopherols in different vegetable oils. The results were compared with analyses performed by traditional chromatographic methods. Graphical abstract.

A fast and accurate methodology for the quantification of the most abundant flavanone glycosides in citrus beverages has been developed. The approach relies on the use of paper spray mass spectrometry, which allows to record data in few minutes and without sample pre-treatment. The experiments have been carried out in Multiple Reaction Monitoring scan mode, in order to obtain the best specificity and sensitivity. The analytical parameters were all satisfactory. The results coming from the analysis of real samples were compared to the data obtained by the commonly used chromatographic method, proving the robustness of the proposed approach.

The exact chemical structure of non-crystallising natural products is still one of the main challenges in Natural Sciences. Despite tremendous advances in total synthesis, the absolute structural determination of a myriad of natural products with very sensitive chemical functionalities remains undone. Here, we show that a metal-organic framework (MOF) with alcohol-containing arms and adsorbed water, enables selective hydrolysis of glycosyl bonds, supramolecular order with the so-formed chiral fragments and absolute determination of the organic structure by single-crystal X-ray crystallography in a single operation. This combined strategy based on a biomimetic, cheap, robust and multigram available solid catalyst opens the door to determine the absolute configuration of ketal compounds regardless degradation sensitiveness, and also to design extremely-mild metal-free solid-catalysed processes without formal acid protons.

A fast methodology for the assay of parabens in drug and cosmetic preparations has been presented. The procedure developed is based on paper spray tandem mass spectrometry and isotope dilution approach. For each investigated paraben, the corresponding labeled standard has been used in order to improve the accuracy and reproducibility of the analyses. The MS experiments have been performed under MRM conditions, monitoring the transitions [M-H]- → m/z 92 and [M-H]- → m/z 98, respectively, for each analyte and the corresponding labeled internal standard. The quantitative assay has been performed using a calibration curve built from 2 to 15 mg/L. The method accuracy, in all case near 100%, was evaluated using fortified samples at two concentration levels, which are representative of the lower and the higher portion of calibration curve. The good values of LOQ, LOD, and reproducibility confirm the consistency of the developed approach.

[EN] The exact chemical structure of non-crystallising natural products is still one of the main challenges in Natural Sciences. Despite tremendous advances in total synthesis, the absolute structural determination of a myriad of natural products with very sensitive chemical functionalities remains undone. Here, we show that a metal-organic framework (MOF) with alcohol-containing arms and adsorbed water, enables selective hydrolysis of glycosyl bonds, supramolecular order with the so-formed chiral fragments and absolute determination of the organic structure by single-crystal X-ray crystallography in a single operation. This combined strategy based on a biomimetic, cheap, robust and multigram available solid catalyst opens the door to determine the absolute configuration of ketal compounds regardless degradation sensitiveness, and also to design extremely-mild metal-free solid-catalysed processes without formal acid protons. Elucidation of the chemical structure of natural products constitutes one of the main challenges in Natural Sciences. Here, the authors show that an amino acid-based metal-organic framework exhibits hydrolase-like catalytic activity and crystallographic determination of the resulting products, This work was supported by the Ministero dell'Istruzione, dell'Universita e della Ricerca (Italy) and the MINECO (Spain) (Projects CTQ2016-75671-P, CTQ 2017-86735-P, RTC-2017-6331-5, Severo Ochoa program SEV-2016-0683 and Excellence Unit "Maria de Maeztu" MDM-2015-0538). R.B. thanks the MIUR (Project PON R&I FSE-FESR 2014-2020) for grant. L.B wishes to thank Italian MIUR for grant n. AIM1899391-1 in the framework of the project "Azione I.2, Mobilita dei Ricercatori, PON R&I 2014-2020". Thanks are also extended to the "2019 Post-doctoral Junior Leader-Retaining Fellowship, la Caixa Foundation (ID100010434 and fellowship code LCF/BQ/PR19/11700011" (J. F.-S.). S. S.-N. thanks ITQ for the concession of a contract. D.A. acknowledges the financial support of the Fondazione CARIPLO/"Economia Circolare: ricerca per un futuro sostenibile" 2019, Project code: 2019-2090, MOCA. E.P. acknowledges the financial support of the European Research Council under the European Union's Horizon 2020 research and innovation program/ERC Grant Agreement No. 814804, MOF-reactors.

In the bergamot (Citrus bergamia) processing cycle, peel and juice are the main by-products. Considering their high content in bioactive and aromatic compounds, the aim of this study was to valorise them in the vinegar industry. The proposal constitutes a model system for the global citrus industry, to improve the commercial value of the citrus wastes. The bioconversion of four juice combinations (based on bergamot fruit peel or juice) in eight wines and, after random choice, in four vinegars was tested. The chemical composition of wines and vinegars was determined, detecting a high permanence of a majority of the compounds of interest. The sensory analysis of the four vinegars before and after an oxidation treatment was performed obtaining good performances.

We report a novel metal–organic framework (MOF) featuring functional pores decorated with hydroxyl groups derived from the natural amino acid L-serine, which is able to establish specific interactions of different natures, strengths and directionalities with organic molecules of technological interest, i.e. ascorbic acid, pyridoxine, bupropion and 17-β-estradiol, based on their different sizes and chemical natures. The ability of 1 to distinctly organize guest molecules within its channels, through the concomitant effect of different directing supramolecular host–guest interactions, enables gaining unique insights, by means of single-crystal X-ray crystallography, into the host–guest interactions. These results increase our understanding of molecular recognition processes in MOFs, opening a myriad of potential technological applications in the near future.

Here we have studied the complexation of naringin with Al(III) under physiological conditions (i.e., at 37 °C and in 0.16 mol L−1 NaCl). Solubility and protonation constants of the ligand were first determined in order to evaluate the competition of naringin for the Al(III) and H+ ions. Speciation analysis made by potentiometric titrations and supported by UV data shows that a complexation occurs at a 1 : 1 ligand-to-Al(III) stoichiometric ratio. Notably, these data combined with mass spectrometry results indicate that the complexation site is located on the β-hydroxy ketone moiety.

A rapid analytical method for the determination of phenylethanoids content in extra virgin olive oil has been developed. The method intends to address the European regulation EU 432/2012 on health claims, which allows to report on the front label of olive oil, the positive health effects due to the consumption of this food. The innovative method is based on paper spray tandem mass spectrometry using deuterated standards. It relies on a two-step analysis, needed to assess the free form of tyrosol and hydroxytyrosol and their ester conjugates after hydrolysis treatment. Different olive oil samples have been analyzed and the classical analytical parameters such as accuracy, LOQ and LOD were calculated from fortified samples. The good values of the latters show the reliability of the new approach, that limits the time of analysis and sample preparation to few minutes.

A simple and fast method based on paper spray mass spectrometry for the determination of caffeine in commercial beverages and drugs has been developed; the analyses were carried out in MRM mode, monitoring the transitions m/z 195 → m/z 138 for caffeine and m/z 198 → m/z 140 for the labeled internal standard. To verify the reliability of the proposed approach, a spiked sample (soda drink and paracetamol tablet) with a known amount of caffeine has been prepared and analyzed by PS-MS, providing accuracy values about 100 %; the LOQ and LOD values were calculated at 1.2 and 1.6 μg/mL, respectively. Both beverages and drugs were also analyzed with the classic analytical method based on LC-UV measurements, showing consistent results between the two approaches, thus confirming the reliability of the developed ambient MS determination. Graphical Abstract The assay of caffeine by paper mass spectrometry.

Here, we show that a 2:1 mixture of Brutieridin and Melitidin, termed “BMF”, has a statin-like properties, which\ud blocks the action of the rate-limiting enzyme for mevalonate biosynthesis, namely HMGR (3-hydroxy-3-methylglutaryl-\ud CoA-reductase). Moreover, our results indicate that BMF functionally inhibits several key characteristics\ud of CSCs. More specifically, BMF effectively i) reduced ALDH activity, ii) blocked mammosphere\ud formation and iii) inhibited the activation of CSC-associated signalling pathways (STAT1/3, Notch and Wnt/\ud beta-catenin) targeting Rho-GDI-signalling. In addition, BMF metabolically inhibited mitochondrial respiration\ud (OXPHOS) and fatty acid oxidation (FAO). Importantly, BMF did not show the same toxic side-effects in normal\ud fibroblasts that were observed with statins. Lastly, we show that high expression of the mRNA species encoding\ud HMGR is associated with poor clinical outcome in breast cancer patients, providing a potential companion\ud diagnostic for BMF-directed personalized therapy.

In this work we have studied the complexation of curcumin (HCur, 1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) with Al(III) and Fe(III) at 37 °C and in 0.16 M NaCl. The protonation constant of curcumin was also determined to evaluate the competition of the ligand for the metal cations and H+. Speciation profiles obtained by potentiometric titrations show that in aqueous solution a complexation occurs at 1:1 ligand-to-cations ratio. With the aim to define the coordination sites of curcumin with these metal ions a mass spectrometry and UV–Vis spectroscopy characterization was carried out. It was found that aluminum binds to the keto-enol moiety of curcumin, while iron binds to the guaiacol (2-methoxyphenol) one. This unexpected experimental evidence was supported by a thorough computational study.

We report a new chiral coordination polymer, prepared from the cytidine 5′-monophosphate (CMP) nucleotide, capable of separating efficiently (enantiomeric excess of ca. 100%) racemic mixtures of L- and D-Asp in a temperature-dependent manner. The crystal structure of the host–guest adsorbate, with the D-Asp guest molecules loaded within its channels, could be solved allowing a direct visualization of the chiral recognition process.

A rapid and reliable method to assay the total amount of tyrosol and hydroxytyrosol derivatives in extra virgin olive oil has been developed. The methodology intends to establish the nutritional quality of this edible oil addressing recent international health claim legislations (the European Commission Regulation No. 432/2012) and changing the classification of extra virgin olive oil to the status of nutraceutical. The method is based on the use of high-performance liquid chromatography coupled with tandem mass spectrometry and labeled internal standards preceded by a fast hydrolysis reaction step performed through the aid of microwaves under acid conditions. The overall process is particularly time saving, much shorter than any methodology previously reported. The developed approach represents a mix of rapidity and accuracy whose values have been found near 100% on different fortified vegetable oils, while the RSD% values, calculated from repeatability and reproducibility experiments, are in all cases under 7%. Graphical abstract Schematic of the methodology applied to the determination of tyrosol and hydroxytyrosol ester conjugates.