Determination of HPLC-UV Fingerprints of Spanish Paprika (Capsicum annuum L.) for Its Classification by Linear Discriminant Analysis

Abstract

The development of a simple HPLC-UV method towards the evaluation of Spanish paprika’s phenolic profile and their discrimination based on the former is reported herein. The approach is based on C18 reversed-phase chromatography to generate characteristic fingerprints, in combination with linear discriminant analysis (LDA) to achieve their classification. To this aim, chromatographic conditions were optimized so as to achieve the separation of major phenolic compounds already identified in paprika. Paprika samples were subjected to a sample extraction stage by sonication and centrifugation; extracting procedure and conditions were optimized to maximize the generation of enough discriminant fingerprints. Finally, chromatograms were baseline corrected, compressed employing fast Fourier transform (FFT), and then analyzed by means of principal component analysis (PCA) and LDA to carry out the classification of paprika samples. Under the developed procedure, a total of 96 paprika samples were analyzed, achieving a classification rate of 100% for the test subset (n = 25).

Determination of Phenolic Compounds in Paprika by Ultrahigh Performance Liquid Chromatography–Tandem Mass Spectrometry: Application to Product Designation of Origin Authentication by Chemometrics

“…Sample treatment was performed following a previously described method. 1,28 Briefly, 0.3 g of paprika were extracted with 3 mL of a water:acetonitrile (20: A quality control (QC) solution was prepared by mixing 50 µL of each sample extract. This QC was employed to evaluate the repeatability of the method and the robustness of the chemometric results.…”

Classification and Authentication of Paprika by UHPLC-HRMS Fingerprinting and Multivariate Calibration Methods (PCA and PLS-DA)

“…For that purpose, 105 paprika samples belonging to different PDO and production regions (La Vera PDO, Murcia PDO, and the Czech Republic), all of them including samples with different taste varieties, were analyzed. A simple and generic sample extraction method using water:acetonitrile 20:80 (v/v) as extracting solvent was proposed [1,19,22,23]. Reversed-phase UHPLC on a C18 column under universal gradient elution with water and acetonitrile (both of them with 0.1% formic acid) as mobile phase components were selected for the chromatographic separation.…”

Targeted UHPLC–HRMS (Orbitrap) Polyphenolic and Capsaicinoid Profiling for the Chemometric Characterization and Classification of Paprika with Protected Designation of Origin (PDO) Attributes

“…As previously commented, the present work aimed to develop a targeted-UHPLC-HRMS profiling method to obtain discriminant paprika chemical descriptors that able to address sample classification regarding both the paprika production region (and PDO) and the paprika flavor variety. For this purpose, the paprika samples were analyzed through reversed-phase chromatography using a C18 column under universal gradient elution, with water and acetonitrile (both with 0.1% formic acid) as the mobile phase components, after a simple sample extraction with water:acetonitrile 20:80 (v/v), as previously reported [28,29,46]. As an example, Figure 1 shows the UHPLC-HRMS total ion chromatograms and the selected ion chromatogram for the ferulic acid (m/z 193.0506) of three selected sweet paprika samples belonging to different production regions (La Vera PDO, Murcia PDO, and the Czech Republic).…”

“…At this stage, a mass resolution of 17,500 FWHM (at m/z 200), an AGC value of 2.0 × 10 5 , and an IT value of 200 ms were employed. Sample treatment was carried out, following a previously described method [28,29,46]. In brief, 0.3 mg of paprika powder was extracted with 3 mL of water:acetonitrile 20:80 (v/v) solution, by stirring in a vortex mixer (Stuart, Stone, United Kingdom) for 1 min, and by sonication (2510 Branson ultrasonic bath, Hampton, NH, USA) for 15 min.…”

“…Within this context, the substitution of ingredients, the addition of (illegal) substances and false declaration of origin are important and challenging issues to the authorities and the food industry. Both targeted and non-targeted (fingerprinting) methodologies-some in combination with multivariate chemometric methods such as principal component analysis (PCA) and partial least squares regression-discriminant analysis (PLS-DA) have been proposed to address paprika classification and authentication issues [13,29,[39][40][41][42][43][44][45][46]. As an example, we recently proposed a UHPLC-MS/MS method, using a triple quadrupole instrument for the determination of 36 polyphenols and phenolic compounds in paprika samples, which was applied to PDO authentication by PCA and PLS-DA [28].…”