Study on the phenolic composition and antioxidant properties of white-, yellow-, and black-corn (Zea mays L.) foodstuffs

BACKGROUNDBlack corn possesses potent antioxidants, but these are mostly lost during processing. In this study we evaluated the antioxidant content of two different black ('Millo Corvo') corn-based products (i.e. tortillas and cookies) subject to moderate processing. A parallel study on white and yellow corns was carried out for comparison. RESULTSRaw 'Millo Corvo' flour exhibited higher contents of phenolic acids, flavonoids, and particularly anthocyanins than white and yellow flours did. Phenolic acids decreased in cookies but did not in tortillas; flavonoids did not exhibit a clear tendency, and anthocyanins were always preserved. Antioxidant activity (AA) obtained for 'Millo Corvo' samples was twice as high as the value measured in white and yellow corns in terms of 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. The difference in AA was even more remarkable in terms of photochemiluminiscence antiradical activity. The conditions used during the cookie-making process enabled the natural antioxidant characteristics of 'Millo Corvo' to be preserved. However, the conditions applied to prepare tortillas resulted in major losses. CONCLUSIONSThe initial phenolics, in particular anthocyanins, and AA of 'Millo Corvo' flour can be maintained during processing as long as the conditions applied are 183 degrees C for 20 min in the absence of a high water content. Millo corvo products possess improved antioxidant characteristics compared with those from white and yellow corns. Millo corvo is a promising black corn type to prepare health-promoting corn-based foodstuffs. (c) 2023 Society of Chemical Industry.