Characterization of Sparkling Wines According to Polyphenolic Profiles Obtained by HPLC-UV/Vis and Principal Component Analysis

Cava is a sparkling wine obtained by a secondary fermentation in its own bottle. Grape skin contains several compounds, such as polyphenols, which act like natural protectors and provide flavor and color to the wines. In this paper, a previously optimized method based on reversed phase high performance liquid chromatography (HPLC) with ultraviolet/visible (UV/Vis) detection has been applied to determine polyphenols in cava wines. Compounds have been separated in a C18 core-shell column using 0.1% formic acid aqueous solution and methanol as the components of the mobile phase. Chromatograms have been recorded at 280, 310 and 370 nm to gain information on the composition of benzoic acids, hidroxycinnamic acids and flavonoids, respectively. HPLC-UV/vis data consisting of compositional profiles of relevant analytes has been exploited to characterize cava wines produced from different base wine blends using chemometrics. Other oenological variables, such as vintage, aging or malolatic fermentation, have been fixed over all the samples to avoid their influence on the description. Principal component analysis and other statistic methods have been used to extract of the underlying information, providing an excellent discrimination of samples according to grape varieties and coupages

Liquid chromatographic cpproach for the discrimination and classification of cava samples based on the phenolic composition using chemometric methods

Phenolic profiles obtained by liquid chromatography with UV/vis detection were here exploited to classify cava samples from the protected designation of origin Cava. Wine samples belonging to various classes which differed in grape varieties, blends and fermentation processes were studied based on profiling and fingerprinting approaches. Hence, concentrations of relevant phenolic acids and chromatograms registered at 310 nm were preliminarily examined by Principal Component Analysis (PCA) to extract information on cava classes. It was found that various hydroxybenzoic and hydroxycinnamic acids such as gallic, gentisic, caffeic or caftaric acids were up- or down-expressed depending on the wine varieties. Additionally, Partial Least Squares Discriminant Analysis (PLS-DA) was applied to classify the cava samples according to varietal origins and blends. The classification models were established using well-known wines as the calibration standards. Subsequently, models were applied to assign unknown samples to their corresponding classes. Excellent classification rates were obtained thus proving the potentiality of the proposed approach for characterization and authentication purposes

Macroprudential policy : objectives, instruments and indicators

Este documento presenta el marco analítico desarrollado recientemente por el Banco de España para la puesta en marcha de su política macroprudencial. La metodología descrita incorpora un amplio conjunto de indicadores que permiten realizar un seguimiento de los riesgos macroprudenciales a través de un mapa de riesgos. El marco servirá de soporte para definir la orientación general de la política macroprudencial del Banco de EspañaThis document presents the analytical framework recently developed by the Banco de España for the implementation of its macroprudential policy. The methodology described uses a broad set of indicators that enables macroprudential risks to be monitored through risk mapping. This framework will provide support for the Banco de España’s broad macroprudential policy stanc

Recent advances in the determination of biogenic amines in food samples by (U)HPLC

The determination of biogenic amines (BAs) in food products stirs up an increasing interest because of the implications in toxicological and food quality issues. Apart from these aspects, in the last years, the relevance of BAs because of some organoleptic and descriptive concerns has been pointed out by several researchers. This overview aims at revising recent advances in the determination of BAs in food samples based on liquid chromatography. In particular, papers published in the last five years have been commented. Special attention has been paid in the great possibilities of ultra-high performance liquid chromatography and high-resolution mass spectrometry. Regarding applications, apart from the determination of BAs in a wide range of food matrices, novel lines of research focused on the characterization, classification and authentication of food products based on chemometrics have also been discussed

Size exclusion coupled to reversed-phase líquid chromatography for the characterization of cranberry products

A combination of solvent extraction, size exclusion purification and reversed-phase liquid chromatography with UV absorption and fluorescence detection was here used for the determination of flavan-3-ols and related oligomeric compounds in cranberry products. The method relied on robust, simple and inexpensive instrumental equipment present in most of routine analytical laboratories. Sample extracts in methanol/water/hydrochloric acid solution (60:39:1, v:v:v) were subjected to sizeexclusion chromatography (SEC) using Sephadex LH-20 as the sorbent to separate simple phenolic and oligomeric components. As a novel aspect of this work, the implementation of the SEC process in a reusable packed column was practically and economically highly advantageous. Fractions were analyzed by reversed-phase chromatography using a C18 core-shell analytical column and 0.1% formic acid aqueous solution and methanol as the components of the mobile phase. Chromatograms were recorded by UV absorption spectroscopy at 280 nm and by fluorescence spectroscopy at lex 280 nm / lem 347 nm. The method was applied to the determination of flavan-3-ols in various cranberry samples. Catechin, epicatechin and procyanidins A2 and B2 were found in different amounts depending on the cranberry varieties

HPLC fingerprints for the authentication of cranberry-based products based on multivariate calibration approaches

This work introduces the topic of the authentication of cranberry-based products and the detection and quantification of possible adulterations with other raw materials of lower quality. For such a purpose, genuine and adulterated cranberry samples were analyzed by reversed-phase HPLC with UV detection. Sample components were separated using an elution gradient based on 0.1% (v/v) formic acid aqueous solution and methanol as the components of the mobile phase. Chromatograms were recorded at 280, 370 and 520 nm. Data resulting from the injection of pure and adulterated samples, consisting of chromatographic fingerprints at each detection wavelength, were analyzed chemometrically. Preliminary studies by Principal Component Analysis showed that the sample extracts were clearly distributed depending on the extent of adulteration. Data was further treated by Partial Least Square regression to determine the percentages of grape contamination. It was found that even mixture samples containing low percentages of grape could be distinguished from genuine cranberry extracts. Besides, results obtained were highly satisfactory, with overall quantification errors lower than 5%. As a conclusion, the method proposed here resulted in an excellent approach to carry out the authentication of cranberry-based products relying on polyphenolic fingerprints

Organic acid profiling by liquid chromatography for the characterization of base vines and sparkling wines

A rapid and reliable method based on liquid chromatography with UV detection has been developed here to determine the main organic acids in base and sparkling wines of the protected designation of origin Cava. Compounds have been separated by reversed-phase mode with a water/acetonitrile solution (95:5 v/v adjusted to pH 2). Figures of merit established at 210 nm are fully compatible with the wine analysis, with correlation coefficients better than 0.996, repeatabilities around 2%, and detection limits generally below 1 g L-1. A total of 53 base wine and 140 cava samples from differentcoupageshave been analyzed. Compositional profiles of organic acids have been used as the source of analytical information for characterization and classification purposes. Results have shown that varietal and blending issues, malolactic fermentation, and tartaric acid stabilization affect the composition of organic acids

Liquid Chromatography-High-resolution Mass Spectrometry (LC-HRMS) Fingerprinting and Chemometrics for Coffee Classification and Authentication

Nowadays, the quality of natural products is an issue of great interest in our society due to the increase in adulteration cases in recent decades. Coffee, one of the most popular beverages worldwide, is a food product easily adulterated. To prevent fraudulent practices, it is necessary to develop feasible methodologies to authenticate and guarantee not only the coffee origin but also its variety, as well as its roasting degree. In the present study, a C18 reversed-phase liquid chromatography (LC) technique coupled to high-resolution mass spectrometry (HRMS) was applied to address the characterization and classification of Arabica and Robusta coffee samples from different production regions using chemometrics. The proposed non-targeted LC-HRMS method using electrospray ionization in negative mode was applied to the analysis of 306 coffee samples belonging to different groups depending on the variety (Arabica and Robusta), the growing region (e.g., Ethiopia, Colombia, Nicaragua, Indonesia, India, Uganda, Brazil, Cambodia and Vietnam), and the roasting degree. Analytes were recovered with hot water as the extracting solvent (coffee brewing). The data obtained was considered the source of potential descriptors to be exploited for the characterization and classification of the samples using principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA). Besides, different adulteration cases, involving nearby production regions and different varieties, were evaluated by pairs (e.g., Vietnam Arabica – Vietnam Robusta, Vietnam Arabica – Cambodia and Vietnam Robusta – Cambodia). The coffee adulteration studies carried out by partial least squares (PLS) regression demonstrated the good capability of the proposed methodology to quantify adulterant levels down to 15%, accomplishing calibration and prediction errors below 2.7% and 11.6%, respectively

Trends in LC-MS and LC-HRMS analysis and characterization of polyphenols in food

Polyphenols comprise a large family of naturally occurring secondary metabolites of plant-derived foods and are among the principal micronutrients associated with the health beneficial effects of our diet. Liquid chromatography coupled to mass spectrometry (LC-MS) and, in the last few years, high resolution mass spectrometry (LC-HRMS) is playing an important role in the research of polyphenols, not only for the determination of this family of compounds in food matrices, but also for the characterization and identification of new polyphenols, as well as the classification and authentication of natural extracts in the prevention of frauds. The purpose of this review is to describe recent advances in the LC-MS and LC-HRMS analysis and characterization of polyphenols in food focusing on the most relevant applications published in the last years. Trends regarding sample treatment, chromatographic separation, mass analyzers and chemometric approaches used in the determination and characterization of polyphenols will be addressed

Authenticity assessment and fraud quantitation of coffee adulterated with chicory, barley and blours by untargeted HPLC-UV-FLD fingerprinting and chemometrics

Coffee, one of the most popular drinks around the world, is also one of the beverages most sus-ceptible of being adulterated. Untargeted high-performance liquid chromatography with ultra-violet and fluorescence detection (HPLC-UV-FLD) fingerprinting strategies in combination with chemometrics were employed for the authenticity assessment and fraud quantitation of adulter-ated coffees involving three different and common adulterants: chicory, barley and flours. The methodologies were applied after a solid-liquid extraction procedure with a methanol:water 50:50 (v/v) solution as extracting solvent. Chromatographic fingerprints were obtained using a Kinetex® C18 reversed-phase column under gradient elution conditions using 0.1% formic acid aqueous solution and methanol as mobile phase components. The obtained coffee and adulter-ants extract HPLC-UV-FLD fingerprints were evaluated by partial least squares regres-sion-discriminants analysis (PLS-DA) resulting to be excellent chemical descriptors for sample discrimination. 100% classification rates for both PLS-DA calibration and prediction models were obtained. Besides, Arabica and Robusta coffee samples were adulterated with chicory, bar-ley and flours, and the obtained HPLC-UV-FLD fingerprints subjected to partial least squares (PLS) regression, demonstrating the feasibility of the proposed methodologies to assess coffee authenticity and to quantify adulteration levels (down to 15%), showing both calibration and prediction errors below 1.3% and 2.4%, respectively