Optimized and validated method for simultaneous extraction, identification and quantification of flavonoids and capsaicin, along with isotopic composition, in hot peppers from different regions.

Nineteen hot pepper (Capsicum annuum L.) samples from five countries and twenty samples from Romanian producers were analyzed. Concentrations of flavonoids and capsaicin were simultaneously quantified for the first time with the method developed and validated in the present paper. δ13C, δ2H, and δ18O isotopic values were also measured. Maximum concentrations of studied compounds were detected in methanol extracts, after 12 h incubation of the samples assisted by ultrasound, at the 1:8 ratio of sample to solvent. The extraction recovery ranged from 90.60% to 115.05%. Capsaicin and four flavonoids were quantified in studied samples at different concentration ranges: capsaicin (28.23-2322.35 µg/g), vitexin (2.93-33.46 µg/g), isoquercetin (3.19-155.58 µg/g), kaempferol-3-glucoside (2.31-2462.25 µg/g) and myricetin (1.55-78.79 µg/g). The association between these analytical techniques and chemometric tools proved that kaempferol-3-glucoside is one of the strongest markers for country and maturity stage discrimination.

Isotopic and multielemental fingerprinting of organically and conventionally grown potatoes.

Two marker combinations were used for the differentiation of organically produced from conventionally produced potatoes and also for the geographical origin identification. Fifty-seven samples (from Romanian local producers or imported) were analysed from the stable isotopic (isotope ratio mass spectrometry) and elemental profile (inductively coupled plasma mass spectrometry) point of view. In order to assess the best marker combination, both isotopic and elemental experimental results were subject to chemometric analysis. The statistical tests performed were ANOVA test, Pearson correlation, principal component analysis and linear discriminant analysis (LDA). For a more comprehensive differentiation between organic vs. conventional potato samples, LDA was applied, and 94.7 % of original cases were correctly classified and the percentage obtained in cross-validation procedure was 91.2 %. Regarding the geographic origin classification, LDA provided an initial classification of 96.5 %, while for cross-validation the percentage was 87.7. LDA found δ15N, Cd, Ca, Cu and Zn as best discrimination markers between organically and conventionally grown potatoes. The strongest predictors for Romania vs. foreign geographical areas along LDA were seen to be Ca, P, Co, Ni and δ13C.