Characterization of turmeric and curry samples by liquid chromatography with spectroscopic detection based on polyphenolic and curcuminoid contents

This paper deals with the characterization of turmeric and related products using the compositional fingerprints of curcuminoids (e.g. curcumin, demethoxycurcumin and bisdemethoxycurcumin) and other phenolic compounds (e.g. hydroxybenzoic and hydroxycinnamic acids, and flavonoids) as the source of analytical information. Under this approach, the quantitative determination of analytes becomes unnecessary and even data from unknown components can be advantageously exploited for sample exploration and authentication. The methodology relied on sample extraction with hydro-organic solvents to recover the components of interest and further analysis of the corresponding extracts by liquid chromatography with diode array detection (HPLC-DAD). Extraction conditions were optimized focusing on the independent recovery of curcuminoids and polyphenols. Two different HPLC methods under reversed-phase mode were used to generate the chromatographic fingerprints at 420 and 280 nm for the specific monitoring of curcuminoids and polyphenols, respectively. Both extraction and separation steps were optimized under experimental design approaches to achieve the richest compositional fingerprints in terms of variety of components. The resulting data was subsequently treated chemometrically by principal component analysis (PCA) and related classification methods to achieve a better overall description of samples. Polyphenolic fingerprints were appropriate to discriminate among turmeric and mixed spices while curcuminoid fingerprints could be useful to distinguish turmeric varieties

Targeted UHPLC-HRMS (Orbitrap) polyphenolic and capsaicinoid profiling for the chemometric characterization and classification of paprika with protected designation of origin (PDO) attributes

Society's interest in the quality of food products with certain attributes has increased, the attribute of a Protected Designation of Origin (PDO) being an effective tool to guarantee the quality and geographical origin of a given food product. In Spain, two paprika production areas with PDO (La Vera and Murcia) are recognized. In the present work, targeted UHPLC-HRMS polyphenolic and capsaicinoid profiling through the TraceFinderTM screening software, using homemade accurate mass databases, was proposed as a source of chemical descriptors, to address the characterization, classification, and authentication of paprika. A total of 126 paprika samples from different production regions¿Spain (La Vera PDO and Murcia PDO) and the Czech Republic, each including different flavor varieties, were analyzed. UHPLC-HRMS polyphenolic profiles showed to be good chemical descriptors to achieve paprika classification and authentication, based on the production region, through principal component analysis and partial least squares regression-discriminant analysis, with classification rates of 82%, 86%, and 100% for La Vera PDO, Murcia PDO, and the Czech Republic, respectively. In addition, a perfect classification was also accomplished among the flavor varieties for the Murcia PDO and Czech Republic samples. By employing the UHPLC-HRMS polyphenolic and capsaicinoid profiles as chemical descriptors, acceptable discrimination among La Vera PDO flavor varieties was also achieved

Classification and authentication of paprika by UHPLC-HRMS fingerprinting and multivariate calibration methods (PCA and PLS-DA)

In this study, the feasibility of non-targeted UHPLC-HRMS fingerprints as chemical descriptors to address the classification and authentication of paprika samples was evaluated. Non-targeted UHPLC-HRMS fingerprints were obtained after a simple sample extraction method and C18 reversed-phase separation. Fingerprinting data based on signal intensities as a function of m/z values and retention times were registered in negative ion mode using a q-Orbitrap high-resolution mass analyzer, and the obtained non-targeted UHPLC-HRMS fingerprints subjected to unsupervised principal component analysis (PCA) and supervised partial least squares regression-discriminant analysis (PLS-DA) to study sample discrimination and classification. A total of 105 paprika samples produced in three different regions, La Vera PDO and Murcia PDO, in Spain, and the Czech Republic, and all of them composed of samples of at least two different taste varieties, were analyzed. Non-targeted UHPLC-HRMS fingerprints demonstrated to be excellent sample chemical descriptors to achieve the authentication of paprika production regions with 100% sample classification rates by PLS-DA. Besides, the obtained fingerprints were also able to perfectly discriminate among the different paprika taste varieties in all the studied cases, even in the case of the different La Vera PDO paprika tastes (sweet, bittersweet, and spicy) which are produced in a very small region

Characterization of fruit products by capillary zone electrophoresis and liquid chromatography using the compositional profiles of polyphenols. Application to authentication of natural extracts

Capillary zone electrophoresis (CZE) and high performance liquid chromatography (HPLC) were applied to the authentication of fruit products based on the compositional profiles of polyphenols. Various sample treatments were used to maximize the overall recovery of polyphenols or specific fractions, such as phenolic acids or anthocyanins. The resulting CZE and HPLC data were treated with Principal Component Analysis (PCA) showing that samples were mainly clustered according to the fruit of origin, with cranberry- and grape-based products clearly separated in groups. A possible adulterated cranberry extract was analyzed more deeply by high resolution mass spectrometry (HRMS) in order to identify the presence of A-type proanthocyanidins, which are characteristic and more abundant in cranberry-based products. In accordance with PCA interpretation, HRMS results indicated that the suspicious sample was not a cranberry-based product, allowing us to validate and demonstrate the suitability of both CZE- and HPLC-proposed methods for the characterization of fruit-based products

UHPLC-HRMS (Orbitrap) fingerprinting in the classification and authentication of cranberry-based natural products and pharmaceuticals using multivariate calibration methods

UHPLC-HRMS (Orbitrap) fingerprinting in negative and positive H-ESI mode was applied to the characterization, classification and authentication of cranberry-based natural and pharmaceutical products. HRMS data in full scan mode (m/z 100-1500) at a resolution of 70,000 full-width at half maximum was recorded and processed with MSConvert software to obtain a profile of peak intensities in function of m/z values and retention times. A threshold peak filter of absolute intensity (105 counts) was applied to reduce data complexity. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) revealed patterns able to discriminate the analyzed samples according to the fruit of origin (cranberry, grape, blueberry and raspberry). Discrimination among cranberry-based natural and cranberry-based pharmaceutical preparations was also achieved. Both, UHPLC-HRMS fingerprints in negative and positive H-ESI modes, as well as the data fusion of both acquisition modes, showed to be good chemical descriptors to address cranberry extracts authentication. Validation of the proposed methodology showed a prediction rate of 100% of the samples. Obtained data was further treated by partial least squares (PLS) regression to identify frauds and quantify the percentage of adulterant fruits in cranberry-fruit extracts, achieving prediction errors in the range 0.17-3.86%

Detection and quantitation of frauds in the authentication of cranberry-based extracts by UHPLC-HRMS (Orbitrap) polyphenolic profiling and multivariate calibration methods

UHPLC-HRMS (Orbitrap) polyphenolic profiling was applied to the characterization, classification and authentication of cranberry-based natural and pharmaceutical products. 53 polyphenolic standards were characterized to build a user accurate mass database which was then proposed to obtain UHPLC-HRMS polyphenolic profiles by means of ExactFinderTM software. Principal component analysis results showed a good sample discrimination according to the fruit employed. Regarding cranberry-based pharmaceuticals, discrimination according to the presentation format (syrup, sachets, capsules, etc.) was also observed due to the enhancement of some polyphenols by purification and preconcentration procedures. Procyanidin A2 and homogenistic, sinapic, veratric, cryptochlorogenic and caffeic acids showed to be important polyphenols to achieve cranberry-based products discrimination against the other studied fruits. Partial least square regression allowed the determination of adulterant percentages in cranberry-fruit samples. Very satisfactory results, with adulteration quantification errors lower than 6.0% were obtained even at low adulteration levels

Non-targeted HPLC-UV fingerprinting as chemical descriptors for the classification and authentication of nuts by multivariate chemometric methods

Recently, the authenticity of food products have become a great social concern. Considering the complexity of the food chain and that many players are involved between production and consumption, food adulteration practices are raising as it is in fact much easier to conduct fraud without being easily detected. This is the case of nut fruits processed products such as almond flours that can be adulterated with cheaper nuts (hazelnuts or peanuts), giving rise to not only economic fraud but also having important effects on human health. Non-targeted HPLC-UV chromatographic fingerprints were evaluated as chemical descriptors to achieve nut samples characterization and classification using multivariate chemometric methods. Nut samples were extracted by sonication and centrifugation, and defatted with hexane; extracting procedure and conditions were optimized to maximize the generation of enough discriminant features. The obtained HPLC-UV chromatographic fingerprints were then analyzed by means of principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) to carry out the classification of nut samples. The proposed methodology allowed the classification of samples not only according to the type of nut but also based on the nut thermal treatment employed (natural, fried or toasted products)

Determination of polyphenols in spanish wines by capillary zone electrophoresis. Application to wine characterization by using chemometrics

A capillary zone electrophoresis method for the simultaneous determination of twenty polyphenols in wine was developed. The separation was performed using fused-silica capillaries of 75 µm I.D. and a 30 mM sodium tretraborate buffer solution at pH 9.2 with 5% isopropanol as a background electrolyte. A capillary voltage of +25 kV with pressure-assisted (3.5 kPa) separation from min 18 was applied, thus, achieving a total analysis time lower than 20 min. Instrumental quality parameters such as limits of detection (LOD values between 0.3 and 2.6 mg/L), linearity (r2>0.990), and run-to-run and day-to-day precisions (RSD values lower than 6.5% and 15.7%, respectively) were established. Three different calibration procedures were evaluated for polyphenol quantitation in wines: external calibration using standards prepared in Milli-Q water, standard addition, and pseudo-matrix matched calibration using wine as a matrix. For a 95% confidence level, no statistical differences were observed, in general, between the three calibration methods (p-values between 0.11 and 0.84), while for some specific polyphenols, such as cinnamic acid, syringic acid and gallic acid, results were not comparablewhen external calibration used. CZE method using pseudo-matrix matched calibration was then proposed and applied to the analysis of polyphenols in 49 Spanish wines, showing satisfactory results and a wide compositional variation between wines. Electrophoretic profiles and other compositional data (e.g., peak areas of selected peaks) were considered as fingerprints of wines to be used for characterization and classification purposes. The corresponding data were analyzed by PCA in order to extract information on the most significant features contributing to wine discrimination according to their origins. Results showed that a reasonable distribution of wines depending on the elaboration areas was found, being tirosol, gallic, protocatechuic, p-coumaric and caffeic acids some representative discriminant compounds

Determination of polyphenolic profiles by liquid chromatography-electrospray-tandem mass spectrometry for the authentication of fruit extracts

Liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS) was applied to the analysis and authentication of fruit-based products and fruit-based pharmaceutical preparations. A Kinetex C18 reversed-phase column under gradient elution with 0.1 % formic acid aqueous solution and methanol mobile phases was used for the simultaneous determination of 26 polyphenols, allowing an acceptable separation in less than 22 min. Instrumental quality parameters such as limits of detection (LOD, values between 12-14 µg/L for 19 of the 26 analyzed polyphenols), linearity (r2 > 0.991), run-to-run and day-to-day precisions (RSD values lower than 9.9 and 13.5 %, respectively), and accuracy (relative errors lower than 8 %) were established. A simple extraction method, consisting of a sample sonication with acetone:water:hydrochloric acid (70:29.9:0.1 v/v/v) and centrifugation, was proposed. Two calibration procedures, external calibration using standards prepared in water and standard addition, were evaluated for polyphenol quantification in several grape and cranberry fruits and processed fruit products. For a 95 % confidence level, no statistical differences were observed between the two calibration methods (p values between 0.06 and 0.95), denoting that external calibration was suitable enough for the quantitative analysis of polyphenols in fruit-based products. The proposed LC-ESI-MS/MS method was then applied to the analysis of polyphenols in 23 grape-based and cranberry-based natural products and pharmaceutical preparations. Polyphenolic concentration data was then analyzed by principal component analysis (PCA) to extract information of the most significant profile data contributing to authentication of natural extracts according to their fruit of origin

Cooking with elaborate recipes can reduce the formation of mutagenic heterocyclic amines and promote comutagenic amines

Heterocyclic amines (HCAs) are foodborne carcinogens which formation is highly dependent on cooking conditions. HCAs have been commonly quantified in food items prepared with simple procedures. This approach is suitable for elucidating HCAs’ formation, but it reflects partially the contamination in consumed food. In the current investigation, the generation of HCAs has been investigated in fried beef items prepared with elaborated cooking recipes, and their occurrence has been compared with control beef fried without the addition of other ingredients than oil. The food recipes that included a variety of food ingredients had lower yields of mutagenic HCAs (≥ 47% reduction, with individual HCA levels ranging between 0.01 and 2.22 ng/g) with respect to the control beef. In contrast, the co-mutagens norharman and harman were formed generally at greater levels (up to 3 times the contamination in the control fried beef) in the items prepared including greater variety of ingredients