Metabolomic fingerprinting employing DART-TOFMS for authentication of tomatoes and peppers from organic and conventional farming.

The rapidly growing demand for organic food requires the availability of analytical tools enabling their authentication. Recently, metabolomic fingerprinting/profiling has been demonstrated as a challenging option for a comprehensive characterisation of small molecules occurring in plants, since their pattern may reflect the impact of various external factors. In a two-year pilot study, concerned with the classification of organic versus conventional crops, ambient mass spectrometry consisting of a direct analysis in real time (DART) ion source and a time-of-flight mass spectrometer (TOFMS) was employed. This novel methodology was tested on 40 tomato and 24 pepper samples grown under specified conditions. To calculate statistical models, the obtained data (mass spectra) were processed by the principal component analysis (PCA) followed by linear discriminant analysis (LDA). The results from the positive ionisation mode enabled better differentiation between organic and conventional samples than the results from the negative mode. In this case, the recognition ability obtained by LDA was 97.5% for tomato and 100% for pepper samples and the prediction abilities were above 80% for both sample sets. The results suggest that the year of production had stronger influence on the metabolomic fingerprints compared with the type of farming (organic versus conventional). In any case, DART-TOFMS is a promising tool for rapid screening of samples. Establishing comprehensive (multi-sample) long-term databases may further help to improve the quality of statistical classification models.

[A comparison of selected parameters of potatoes health quality from ecologically oriented and conventional farms]. / Porównanie wybranych parametrów jakosci zdrowotnej ziemniaków z gospodarstw ekologicznych i konwencjonalnych.

The aim of work was to compare nutritional quality and wholesomeness of the potatoes from ecological (ECO) and conventional (CONV) farms. Other aim was to check if the west-european data telling about better nutritional quality of ECO potatoes can be confirmed in Polish agricultural conditions. Nine ECO farms located in Torun and Sieradz provinces, having EKOLAND's certification were selected to study. A neighbour CONV farm with similar production conditions was selected to each ECO farm. ECO farmers manured potatoes with composted cow manure or compost giving on average 30 t/ha. CONV farmers used mineral fertilizers NPK in 1:1:1,5 ratio giving 100 kg N/ha. In the autumn several compounds were determined in potatoes: the contents of dry matter according to PN-88/R-04013, the contents of nitrates and nitrites according to Draft International Standard ISO, the contents of Pb and Cd by means of ASA method and the contents of vitamin C as L-ascorbic acid according to PN-90/A-75101/11. The ECO potatoes contained in both years significantly less nitrates than CONV potatoes. In 1992 the nitrates contents was much higher in both kinds of potatoes than in 1993. The nitrites contents was in both years higher in CONV potatoes but the difference was statistically significant only in 1993. The lead contents was low in both kinds of potatoes and didn't exceed permissible level. The cadmium contents was in 1992 significantly higher in CONV tubers than in ECO tubers and exceeded permissible level. In 1991 and 1993 both kinds of tubers contained similar cadmium levels. The contents of dry matter and vitamin C was similar in both kinds of tubers. The study has shown that ECO potatoes were more wholesome than CONV potatoes. The results obtained in Polish agricultural conditions confirmed west-european data.