## 4 Conclusions  
In this study, a non-targeted NMR screening was performed on a group of authentic staffon samples and on a group of saffron samples intentionally adulterated by the addition of safflower and turmeric at different concentrations. The elaboration of NMR data of aqueous extracts by chemometrics allowed the discrimination between authentic and adulterated saffron samples, detecting the presence of both adulterants at a concentration value equal to 5 wt%. When a similar study was performed on the same samples extracted in DMSO-\(d_{6}\), the presence of turmeric was detected at a concentration level of 5%, while it was possible to identify the presence of safflower only at higher levels of concentration, i.e., 20 wt%. To the best of our knowledge, to date, no non-targeted NMR-based method has been reported in the literature capable of detecting the presence of contaminants at these concentration levels. Furthermore, through the same analytical approach, it was possible to obtain crucial information on the type of cultivation practice adopted for the production of saffron. The results reported in this study can help to enhance the application of non-targeted NMR-based metabolomics in the control processes of the agri-food supply chain with the final goal to valorize sustainable farming practices and ensure traceability and authenticity of food products. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app12052583/s1](https://www.mdpi.com/article/10.3390/app12052583/s1)]([https://www.mdpi.com/article/10.3390/app12052583/s1](https://www.mdpi.com/article/10.3390/app12052583/s1)). Figure S1: Effect of pasteurization step on the stability of aqueous extracts of pure saffron. Table S1: List of metabolites contained in the aqueous extracts of authentic staffon samples and identified by 1D 1H NOESY NMR. Figure S2: Typical 1D \({}^{1}\)H NOESY NMR spectrum of aqueous extracts of authentic staffon. Figure S3: 1D \({}^{1}\)H NOESY NMR spectra of aqueous extracts of authentic staffon, authentic turmeric, authentic stafflower, saffron adulterated with turmeric, and saffron adulterated with safflower. Table S2: List of the top 50 features identified by the Wilcoxon rank-sum test applied to the aqueous extracts of authentic and adulterated saffron samples. Figure S4: Trend of the top six most significant variables according to the Wilcoxon rank sum test applied to the aqueous extracts of authentic and adulterated saffron samples. Figure S5: Results of the hierarchical analysis applied to the spectral data obtained from the aqueous extracts of authentic and adulterated saffron samples. Figure S6: 10-fold cross-validation method applied to the PLS-DA model built on the spectral data obtained from the aqueous extracts for discriminating between authentic and adulterated saffron samples. Figure S7: Permutation test applied to the PLS-DA model built on the spectral data obtained from the aqueous extracts for discriminating between authentic and adulterated saffron samples. Figure S8: Overview of the PLS-DA model built on the spectral data obtained from the aqueous extracts for discriminating  
Figure 8: Results of the hierarchical clustering heat map performed on the normalized data (distance measure using _Euclidean_, and clustering algorithm using _Ward_). Each colored cell on the map corresponds to a concentration value in the data table, with samples in columns and metabolites in rows. The belonging class of samples is indicated as red and green squares for saffron cultivated according to organic farming (B) and conventional (C), respectively. between authentic and adulterated saffron samples. Table S3: List of the top 66 variables importance in projection (VIPs) related to the PLS-DA model built on the spectral data obtained from the aqueous extracts for discriminating between authentic and adulterated saffron samples. Figure S9: Typical \({}^{1}\)H NMR spectrum of extracts of authentic saffron in DMSO-\(d_{6}\).