Authentication of Sorrento walnuts by NIR spectroscopy coupled with different chemometric classification strategie

Walnuts have been widely investigated because of their chemical composition, which is particularly rich in unsaturated fatty acids, responsible for different benefits in the human body. Some of these fruits, depending on the harvesting area, are considered a high value-added food, thus resulting in a higher selling price. In Italy, walnuts are harvested throughout the national territory, but the fruits produced in the Sorrento area (South Italy) are commercially valuable for their peculiar organoleptic characteristics. The aim of the present study is to develop a non-destructive and shelf-life compatible method, capable of discriminating common walnuts from those harvested in Sorrento (a town in Southern Italy), considered a high quality product. Two-hundred-and-twenty-seven walnuts (105 from Sorrento and 132 grown in other areas) were analyzed by near-infrared spectroscopy (both whole or shelled), and classified by Partial Least Squares-Discriminant Analysis (PLS-DA). Eventually, two multi-block approaches have been exploited in order to combine the spectral information collected on the shell and on the kernel. One of these latter strategies provided the best results (98.3% of correct classification rate in external validation, corresponding to 1 misclassified object over 60). The present study suggests the proposed strategy is a suitable solution for the discrimination of Sorrento walnuts. © 2020 by the authors

A rapid and non-invasive method for authenticating the origin of pistachio samples by NIR spectroscopy and chemometrics

In this study, near-infrared spectroscopy coupled to chemometrics is used to build an analytical protocol to authenticate the origin of pistachio nuts (Pistacia vera L.), a high value-added food product. In particular, 483 samples from six different origins (Sicily, India, Iran, Syria, Turkey and U.S.A.) were analyzed by NIR spectroscopy. Spectra were recorded on half seeds cut longitudinally in reflectance mode. Spectral data were then processed by chemometrics to build classification models by SIMCA and PLS-DA. The discriminant approach resulted in classification accuracies higher than 90% for most of the classes. On the other hand, SIMCA built class-models with high sensitivity and specificities, the only exception being the two categories Turkey and Iran, whose heterogeneity resulted in a poorer specificity (anyway higher than 80%). In particular, the results obtained for the samples coming from Bronte (Sicily), the only PDO pistachio production in Europe 95.5% non-error rate in PLS-DA, 90% sensitivity and 97% specificity in SIMCA, as evaluated on the external test set are very promising from the viewpoint of the authentication of this product. In general, the results show that the coupling of NIR spectroscopy to chemometric classification techniques can be a valuable tool for tracing the origin of pistachio nuts, providing a reliable authentication in a rapid, relatively cheap and non-invasive way.Vitale, R.; Bevilacqua, M.; Bucci, R.; Magrì, A.; Magri, A.; Marini, F. (2013). A rapid and non-invasive method for authenticating the origin of pistachio samples by NIR spectroscopy and chemometrics. Chemometrics and Intelligent Laboratory Systems. 121:90-99. doi:10.1016/j.chemolab.2012.11.019S909912

Structural analysis of the solid amorphous binuclear complexes of iron(III) and aluminum(III) with chromium(III)-DTPA chelator using Energy Dispersive X-ray Diffraction

Prepn. and structural data are presented for two amorphous binuclear complexes of Fe(III) and Al(III) with Cr(III)-diethylentriaminepentaacetic acid (Cr(III)-DTPA, CrL2-) using the energy-dispersive x-ray diffraction technique. Fe(OH)CrL(H2O)6 and Al(OH)CrL(H2O)6 are binuclear complexes with the metals ions bridged via O atoms. The metal ions are all octahedrally coordinated

CHROMIUM(III) COMPLEXES WITH DIETHYLENTRIAMINEPENTAACETIC ACID

Abstract Complex formation by chromium(III) with diethylentriaminepentaacetic acid (DTPA) has been studied by potentiometry and spectrophotometry. In equimolar solutions or with a ligand excess, complexation is practically complete at pH > 1 and protonation equilibria have been calculated. Molar absorbtivities of the different species have been evaluated. Equilibrium constants for complex formation have been calculated in 1 mol dm−3 (Na,H)ClO4 at 20°C

Determination of diclofenac salts in pharmaceutical formulations"

Two methods for the determination of the diclofenac salts [sodium (DS) or diethylammonium (DA)] in three pharmaceutical formulations (tablets, suppositories and gel) are presented. In the first, diclofenac salt is determined both, by measuring the absorbance of the solutions at a fixed wavelength (lambda = 276 nm) and using a multi-wavelength computational program to process the spectrophotometric data in a selected range (lambda = 230-340 nm). The above method can not be applied to the analysis of gel formulations because of the opalescence of these solutions. In this case, the analysis is performed measuring the peak-to-peak amplitude in the first-derivative UV spectrum (D-1 261.296). In the second method, diclofenac (DH) is precipitated in acid medium and determined by the analysis of the endothermic peak (t(p) = 182 degrees C) in the DSC curve obtained in nitrogen atmosphere. Finally, some aspects of chemical (solubility, acid-base equilibria, redox reaction), spectroscopic (UV, LR) and thermoanalytical (TG, DSC) behaviour of DS and DH and the values of the parameters which enable to calculate the UV spectrum of DS in aqueous solution are reported

Multilayer feed-forward artificial neural networks for class-modeling

A class-modeling algorithm based on multilayer feed-forward artificial neural networks is proposed. According to this method, each category model is described by an auto-associator network, so the class space is defined on the basis of a distance to the model criterion which takes into account the residual standard deviation of the reconstructed input vectors. The details of the method are discussed and examples of its application to a simulated ("exclusive-OR") and a real-world (classification of wines) problem are presented. As far as the simulated highly non-linear example is concerned, NN-based class modeling outperforms SIMCA and UNEQ both in terms of classification rate and specificity. On the other hand, when dealing with the wine data set, which has a less non-linear structure, our proposed method still provides comparable and, in some cases, better results than the other two techniques

Using thermoanalytical data Part 4. Processing of DTA/DSC curves to calculate reaction enthalpy and kinetic parameters. An application to calcium oxalate

With regard to single step reactions, a new approach to the processing of DTA/DSC curves is presented, taking into account the heat transfer into the instrument. It is an extension of a previous physical model, that allowed the calculation of true kinetic parameters from TG curves. The peak area can be properly calculated as well as the degree of reaction, this also being suitable for kinetic parameters calculation. Through numerical simulations, other methods for DTA/DSC curve processing are discussed with respect to that proposed. By TG and DTA, the true kinetic parameters have been finally determined for the second and third steps of the thermal decomposition of CaC2O4.H2O, to complete previously reported data for the first dehydration step. The agreement of the results with isothermal experiments seems to indicate a way to escape from the dichotomy between isothermal and non-isothermal kinetics. Several other approaches to non isothermal kinetics are reviewed and discussed. The software developed is also briefly described

Using thermoanalytical data. Part 2. The dependence of kinetic data available from thermogravimetry on sample and instrument parameters: a method for calculating ‘true’ kinetic parameters

Abstract Kinetic data available from TG measurements are discussed with respect to thermal coefficients such as sample specific heat, reaction enthalpy, instrument heat-transfer coefficient and heat capacity. The dependence of the available kinetic parameters Z, E and N on these thermal coefficients is examined using a numerical model. A relationship is also derived for calculating the kinetic parameters from experimental TG curves whilst taking into account the perturbation induced by the above-cited thermal coefficients. The dehydration of calcium oxalate is used to evaluate experimentally the predictive power of the kinetic parameters obtained in this way, i.e. their ability to describe the sample behaviour under a wide range of operational conditions (different masses and heating rates), including isothermal reactions