Characterization of Red Radish Anthocyanins

Red radish (Raphanus sativus L.) anthocyanins were extracted from liquid nitrogen powdered epidermal tissue using acetone, partitioned with chloroform and isolated using C-18 resin. The monomeric anthocyanin content, determined by pH-differential, was 154 ± 13 mg/100g epidermal tissue (pelargonidin-glucoside basis). Thermal processing of radishes showed that the pigments were stable to heat. Four major pigments were identified by Mass Spectroscopy, HPLC, and spectral analyses as pelargonidin-3-sophoroside-5-glucoside derivatives. The two major pigments were acylated with malonic acid and either ferulic or p-coumaric acid. The two other pigments were acylated with only ferulic or p-coumaric acid. Acylation increased pigment resistance to acid hydrolysis.