The OrgTrace project: Content, Bioavailability and Health Effects of Trace Elements and Bioactive Components of Food Products Cultivated in Organic and Conventional Agricultural Systems

Trace elements, bioactive secondary metabolites and vitamins are among the most important quality parameters in plants. Yet, very little information is available on their content, bioavailability and health effects in organically grown plant food products. The main objective of OrgTrace is to study the impact of different agricultural management practices relevant for organic farming on the ability of cereal and vegetable crops to absorb trace elements from the soil and to synthesize bioactive compounds (secondary metabolites, antioxidant vitamins and phytates) with health promoting effects. Based on different plant products produced in OrgTrace, diets were composed and the bioavailabilities of health promoting substances were analyzed in a human intervention study. Moreover, various health effects such as immune system responses were studied using rats as model organisms. OrgTrace is the first study, which follows selected elements and bioactive compounds all the way from the plant and soil system to absorption in the human body. All experimental studies have now been finalized and we are able to draw final conclusions

Effect of foliar application of selenium on its uptake and speciation in carrot

Carrot (Daucus carota) shoots were enriched by selenium using foliar application. Solutions of sodium selenite or sodium selenate at 10 and 100 lg Se ml�1, were sprayed on the carrot leaves and the selenium content and uptake rate of selenium were estimated by ICP–MS analysis. Anion and cation exchange HPLC were tailored to and applied for the separation of selenium species in proteolytic extracts of the biological tissues using detection by ICP–MS or ESI–MS/MS. Foliar application of solutions of selenite or selenate at 100 lg Se ml�1 resulted in a selenium concentration of up to 2 lg Se g�1 (dry mass) in the carrot root whereas the selenium concentration in the controls was below the limit of detection at 0.045 lg Se g�1 (dry mass). Selenate-enriched carrot leaves accumulated as much as 80 lg Se g�1 (dry mass), while the selenite-enriched leaves contained approximately 50 lg Se g�1 (dry mass). The speciation analyses showed that inorganic selenium was present in both roots and leaves. The predominant metabolised organic forms of selenium in the roots were selenomethionine and c-glutamyl-selenomethyl- selenocysteine, regardless of which of the inorganic species were used for foliar application. Only selenomethionine was detected in the carrot leaves. The identity of selenomethionine contained in carrot roots and leaves was successfully confirmed by HPLC–ESI–MS/MS