Structural analysis of black common bean (Phaseolus vulgaris L.) anthocyanins

Two anthocyanins were isolated from 1% HCl-20% methanol extracts of KG 97287 black common bean (Phaseolus vulgaris L.) using semipreparative, high-performance liquid chromatography (HPLC). The anthocyanins were identified using a combination of LC/ES-mass spectrometry (MS) and spectroscopic methods of UV-Vis, H-1- and C-13- nuclear magnetic resonance (NMR). The chemical structures of these two anthocyanins were elucidated as delphinidin 3-glucoside and petunidin 3-glucoside and their contents in KG 97287 black common bean seed coats were determined to be 2.614 +/- 0.11 and 0.167 +/- 0.01 mg/g, respectively. These contents were lower than reported internationally and we recommend the introduction into Korea of high anthocyanin varieties of black common bean.