Analysis of Red Amaranth (Amaranthus cruentus L.) Betalains by LC-MS

Betalains are natural pigments responsible for the colour of flowers, bracts, stems, and leaves of genus Amaranthus, and they are bioactive compounds. Due to their great chemical diversity, the determination and confident identification of betalains are still challenges and of great interest as they are natural colourants for health benefit. By high-performance liquid chromatography (LC) coupled to tandem mass spectrometry (MS), the catalog of betalains in red amaranth (Amaranthus cruentus L.) was defined. In total, 30 betacyanins and 13 betaxanthins were found. Mass measurements for the parent ion and for its fragments with errors of less than 5 parts per million (ppm) achieved the recommended criteria for identification of compounds. This work defines the main betalains in red amaranth (A. cruentus) and valorizes the leaves and inflorescence of red amaranth as betalain pigments sources.