Identification and antioxidant activity of anthocyanins extracted from the seed and cob of purple corn (Zea mays L.)

The total anthocyanin content (TAC) and the antioxidant activity of the seed and cob from Chinese purple corn (Zea mays L., cv Zihei) extracts were determined by pH-differential method, and DPPH, FRAP, and TEAC methods, respectively. TAC in purple corn cob anthocyanins (PCCAs) extract was higher than TAC in purple corn seed anthocyanins (PCSAs) extract. Compared to bulylated hydroxytoluene (BHT), PCCAs and PCSAs possessed significantly higher antioxidant activities, according to the DPPH, FRAP and TEAC assays. A satisfactory correlation between TAC and antioxidant activity was observed. Result indicated that cyanidin-3-glucoside, pelargonidin-3-glucoside and peonidin-3-glucoside were components in PCSAs extracts, and seven kinds of anthocyanin had been detected and six kinds of anthocyanin in PCCAs extracts were separated and identified them as cyanidin-3-glucoside, pelargonidin-3-glucoside and peonidin-3-glucoside, and their respective malonated counterparts as their anthocyanins using HPLC–MS analysis.Industrial relevanceIn the last decades, in interest in anthocyanin pigments has increased because of their possible utilization as natural food colorants and especially as antioxidant and anti-inflammatory agents. Purple corn is a pigmented variety of Z.mays L., originally cultivated in Latin America. Now, this corn variety is mainly grown in China, especially in Shanxi and Anhui Province, could be new and interesting sources to obtain extracts rich in anthocyanins for their use in food, pharmaceutical and cosmetic industries. Our results indicated that the seed and cob of purple corn possessed excellent antioxidant activity, which could lead to increased application of these natural food colorants by the food industry.