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Organic foods

Nutritional differences between organic and Conventional foods

A number of studies have addressed the question of whether agricultural chemicals and other agricultural methods including organic farming affect nutrient content. The question is still unresolved. The nutritive composition of plants, including secondary plant metabolites, may be affected by different production systems such as organic and conventional. These systems differ in the amounts of nutrients applied as fertilizers and in organic matter applied to the soil as crop residues, winter legume cover crops or composted manure. The availability of inorganic nitrogen in particular has the potential to influence the synthesis of secondary plant metabolites, proteins and soluble solids. Moreover, organically produced plants have a longer ripening period because of a slower release of the supplied nutrients compared to conventional plants, and as polyphenols are synthesized during the ripening period and the plant syntheses them as phytoalexin under stress conditions, one may expect a higher content of these compounds in organically grown plants. Moreover, when plants are grown with artificial nutrients, they are supposed to lose their natural defense mechanisms. This may result in reduced disease resistance and diluted contents of minerals, vitamins and defense-related secondary metabolites, which are considered beneficial for human health.

To evaluate nutritional differences we use metabolomics aims to assess metabolic differences in a global manner in order to provide a detailed profile of all the polyphenols present in food samples. We apply a HPLC-Q-ToF metabolomic approach followed by multivariate data analysis. The use of QToF technologies allows the exact mass measurements of both MS and MS/MS ions to be achieved, which is essential for elemental composition assignment and thus for the characterization of molecules. In the studies carried out in our group, the growing conditions of tomatoes (conventionalversusorganic) affected the content of phenolic compounds of these vegetables. The organically produced tomatoes displayed a higher phytochemical concentration than conventionally produced tomatoes. Thus, vegetable and fruit products grown in organic agriculture would be expected to be more health-promoting than those produced conventionally.

Publications

Vallverdú-Queralt, A.; Medina-Remón, A.; Casals, I.; Lamuela-Raventos, R.M. (2012) Is there any difference between the phenolic content of organic and conventional tomato juices? Food Chemistry. 130(1):222-227

Vallverdú-Queralt, A.; Medina-Remón, A.;Casals, I.;Amat, M.; Lamuela-Raventos, R.M. (2011) A Metabolomic Approach Differentiates Between Conventional and Organic Ketchups Journal of Agricultural and Food Chemistry.