Enhanced process integration for the extraction, concentration and purification of di-acylated cyanidin from red cabbage

Anthocyanins are currently one of the most important pigments in the plants with great proven health-promoting benefits, however, their unstable chemical nature makes difficult their purification process. This work proposes the integration of two stages for the separation and purification of the pigments from red cabbage leaves. For the first stage, the acidified extract, containing 32.05 mg cyanidin-3-glucoside per milliliter (mg ECyn-3-glu•L⁻¹), was subjected to micro, ultrafiltration and adsorption processes, allowing to concentrate up to 3221.45 mg ECyn-3-glu•L⁻¹ of the pigments after an adsorption process. In the second stage, the pigments were fully fractionated by molecular exclusion chromatography, reverse-phase vacuum liquid chromatography and semi-preparative chromatography, isolating the stable di-acylated cyanidin with antioxidant activity. Finally, purified fractions were also analyzed by NMR analysis.