Triticosecale “Bilinda” (cultivar was bred in the laboratories of the Leningrad Research Agriculture Institute, Branch of Russian Potato Research Centre, Leningrad Province) contains a large number of polyphenolic compounds which are biologically active components. The purpose of this work was to conduct a comparative metabolomic study of extracts of Triticosecale cultivar “Bilinda” seeds harvested at different stages of maturation. To identify target analytes in extracts HPLC was used in combination with an ion trap. The results showed the presence of 93 target compounds corresponding to Triticosecale. In addition to the reported polyphenol constituents, 28 polyphenols were newly annotated in grains of Triticosecale. There were 9 flavones, 7 flavonols, 2 flavan-3-ols, 1 flavanone, 5 hydroxybenzoic acids, 1 hydroxycinnamic acid, 1 anthocyanidin, 1 condensed tannin, 1 hydroxycoumarin, 2 triterpenoids; 1 diterpenoid, 6 sterols, 2 isoquinoline alkaloids, 4 carotenoids, 1 hydroquinone derivative and others bioactive compounds. Metabolic analysis showed a significant difference in the classes and amounts of polyphenolic substances identified in the seeds, depending on the time of seed collection. © TÜBİTAK.