Betalains and phenolics in red beetroot (Beta vulgaris) peel extracts: Extraction and characterisation

The extraction of red beetroot (Bera vulgaris) peel betalains and phenolics was compared with two extraction methods and solvents. The content of tota l phenolics in the extracts was determined according to a modification of t he Folin-Ciocalteu method and expressed as gallic acid equivalents (GAE). T he profiles of extracts were analysed by high-performance liquid chromatogr aphy (HPLC). The compounds of beetroot peel extracted with 80% aqueous meth anol were characterised from separated fractions using HPLC- diode array de tection (HPLC-DAD) and HPLC- electrospray ionisation-mass spectrometry (HPL C-ESI-MS) tech niques. The extraction methods and the choice of solvent aff ected noticeably the content of individual compounds in the extract. The be talains found in beetroot peel extract were vulgaxanthin I, vulgaxanthin II . indicaxanthin, betanin. prebetanin, isobetanin and neobetanin. Also cyclo dopa glucoside, N-formylcyclodopa glucoside, glucoside of dihydroxyindolcar boxylic acid, betalamic acid. L-tryptophan, p-coumaric acid. ferulic acid a nd traces of unidentified flavonoids were detected.