Study on purification and identification of anthocyanins from purple corn bract and its thermal characterization

In order to clarify the anthocyanins composition and assess their thermal characterization in vitro, anthocyanins in the purple corn bract were purified by Amberlite XAD-7 and LH-20 and identified by HPLC-MS. The thermal characterization of anthocyanin was studied by thermogravimetry ( TG) analysis. The results showed that purple corn bract contained 6 kinds of anthocyanins.Three portions were obtained after purifying by LH-20.The first portion was mixture of pelargonidin-3-glucoside and peonidin-3-glucoside, which exhibited the least thermal stability as the second portion containing cyanidin-3-glucoside. The third portion was cyanidin-3- ( 6 ’- malonylglucoside) which exhibited less thermal stability.The total anthocyanin extract purified by Amberlite XAD-7 exhibited the strongest thermal stability.