Betanin from Red Beet (Beta vulgaris L.) Extraction conditions and evaluation of the thermal stability

The aim of this study was to establish the most efficient extraction conditions of betanin and to evaluate the termal stability of this red pigment in aqueous solution. The extraction of betanin from red beet (Beta vulgaris L.) was carried out under different conditions, varying the extraction parameters such as time and solid to solvent ratio, in acidic aqueous medium. The yields of the extracted pigment ranged from 0.303 mg/g to 0.377 mg/g. The highest pigment recovery was achieved when the red beet roots were treated for 60 min at a 1:5 solid-solvent ratio. The impact of storage conditions on the betanin stability was investigated at room temperature (22°C) and at 75°C. The degradation of the red beet pigment followed a first order reaction kinetics, with reaction rate constants of 7·10-3 h-1 and 371·10-3 h-1, respectively.