Using the high-efficiency liquid chromatography, the phenolic compounds of yacon (Polymnia sonchifolia) introduced in Ukraine have been studied. The derivants of hydroxycinnamic acid is prevalent in the ethanol extracts from leaves and roots of yacon. Differences in the contents of  ethanol extracts from fresh and dry roots were shown. The total amount of hydroxycinnamic acids was 2,8 % – 4,3 % depending on the layer of leaves. It was found that roots content 36-45% of fructosans expressed as fructose and dry matter.

The fraction composition and content of phenolic compounds in vegetable plants with high content of polyphenols is presented. The developed functional foods is a complex of antioxidants such as dehydro- quercetine, quercetine, rutin, amaranthine, etc., which can be used for immune system reinforcement, against dysbacteriosis, and promotion of health.