1H NMR metabolic fingerprinting of saffron extracts

Abstract

The aim of this study was to explore feasibility of 1 H NMR metabolic fingerprinting for discrimination of authenticity of saffron using principal component analysis (PCA) modeling. Authentic reference Iranian saffron (n = 31) and commercial samples (n = 32) were used. Cross-validated PCA models based on 1 H NMR spectra of solutions prepared by direct extraction of grinded saffron with methanol-d 4 distinguished reference Iranian saffron samples from commercial samples that formed several distinct clusters, some of which represent falsified samples as confirmed by microscopic analysis. The production sites and drying conditions of the authentic reference Iranian samples were not reflected in the current dataset. Picrocrocin and glycosyl esters of crocetin emerged as the most important 1 H NMR markers of authentic saffron by using statistical correlation spectroscopy. In conclusion, 1 H NMR spectra of saffron extracts combined with pattern recognition by PCA provide immediate means of unsupervised classification of saffron samples.

Evaluation of saffron (Crocus sativus L.) adulteration with plant adulterants by 1H NMR metabolite fingerprinting

“…96, 4.16, 5.40, 6.52, 6.64, 6.84, and 7.32 ppm) in authentic Greek saffron with respect to saffron adulterated with the bulking agents, which generally presented higher levels of fatty acids (buckets at 1.20 and 1.24 ppm) and buckets including specific plant adulterant signals. Our results were in agreement with previously published data (Yilmaz et al, 2010) Table 1 highlighted the model performance in prediction capability; no adulterated sample from any of the four classes was assigned as pure saffron and all samples were correctly classified, by using a classification threshold of 0.6. Only the twelve adulterated test set samples were successively reprojected in the O2PLS-DA model, built on the 28 adulterated saffron samples comprising the training set, resulting in three predictive and two orthogonal components (R 2 X = 93%, R 2 Y = 96.7%, Q 2 = 93.4%).…”

“…NMR based metabolite fingerprinting may identify the subtle differences that often exist between authentic and fraudulent products. As a matter of fact, this metabolomic approach has been recently explored to discriminate authentic Iranian saffron from commercial samples; the results indicated relative amounts of picrocrocin and the sum of different crocetin glycosides as the characteristic metabolites for authentic saffron (Yilmaz, Nyberg, Mølgaard, Asili, & Jaroszewski, 2010). The complexity of NMR data in food metabolomics studies is clearly the primary impetus for the coupling of NMR spectroscopy with multivariate statistical methods, capable of gathering samples with similar features Tomassini, Capuani, Delfini, & Miccheli, 2013).…”

Discrimination and Nitric Oxide Inhibitory Activity Correlation of Ajwa Dates from Different Grades and Origin

“…The use of 1 H-NMR spectroscopy in metabolomics analysis offers several advantages over other techniques, owing to its simple sample preparation, large information content in single spectra and the ability to identify discriminating constituents from spectral features or covariance matrix analysis. Furthermore, 1 H-NMR spectroscopic data are highly reproducible, thus allowing spectral comparison with those in the literature or databases [5]. It is also useful for correlating the chemical constituents of extracts with the biological activity.…”

Authentication of saffron (Crocus sativus L.) using 1H nuclear magnetic resonance (NMR) spectroscopy

“…The nontargeted spectral "fingerprinting approach" is specifically advantageous to detect food fraud with previously unexpected substances. 6 As suggested in several previous studies [3][4][5] , NMR is a highly appropriate technique for saffron authentication. Based on these literature methods, we have developed our measurement protocol and evaluated authentic samples from official food control.…”

“…2 Another rather crude way of adulteration is to use artificial colours to falsify deteriorated natural material or by complete imitation using coloured paper and wood. [3][4][5] For this reason, saffron must be authenticated in food control, e.g. by analysing saffron-specific compounds using nuclear magnetic resonance (NMR) spectroscopic techniques.…”