Background and methodology
Many consumers are aware of the need to eat foods that contain phytochemicals (biologically active chemicals derived from plants) as a way to achieve certain health benefits, and vegetables form an essential part of a well-balanced diet. Brassica vegetables, which include all types of cabbage, are reported to possess certain cancer preventive activity due to glucosinolates and its derived properties. Their leaves have little starch, sugar or fat; their fiber is useful; they contain some vitamin E and a range of B vitamins; and they have a significant amount of carotenes and ascorbic acid.
This study of phytochemicals involved tronchuda cabbage (Brassica oleracea ) cultivated under conventional and organic practices and collected at different times. Six organic acids were identified and quantified by HPLC-UV (high-pressure liquid chromatography with ultra violet detector). Qualitative and quantitative differences were noted between internal and external leaves.
In general, tronchuda cabbages from organic culture have a higher content of phenolics (chemical compounds consisting of a hydroxyl group (-OH) than those from conventional systems. Tronchuda cabbage may be a good source of health-promoting compounds namely, organic acids and phenolic compounds. The results indicated that the inside leaves of this vegetable are different than the external leaves in their phenolic composition: internal leaves have phenolic acid derivatives as the main compound with a small amount of flavonol glycosides (molecules in which a sugar is bound to a non-carbohydrate moiety), whereas external leaves exhibit only flavonol derivatives. Additionally, there are only two phenolic compounds present in both kinds of leaves.
Sousa, C., Valentao, P., Rangel, J., Lopes, G., Pereira, J. A., Ferreres, F., Seabra, R. M., & Andrade, P. B. (2005). Influence of two fertilization regimens on the amounts of organic acids and phenolic compounds of Tronchuda Cabbage (Brassica oleracea L var Costata DC). Journal of Agricultural and Food Chemistry, 53(23), 9128-9132. Available on line at:http://dx.doi.org/10.1021/jf051445f