Antioxidant activity, phenolic compounds and anthocyanins content of eighteen strains of Mexican maize

Free-radical scavenging, reducing activity and some phytochemical content (total phenolic, anthocyanin and ferulic acid) of eighteen Mexican maize phenotypes were determined. Total phenolic contents ranged from 215.8 to 3400.1 mg gallic acid/100 g of whole grain flour and total anthocyanins ranged from 1.54 to 850.9 mg cyanidin-glucoside equivalents/100 g of whole grain flour. Most of the phenolics in grain were in the bound form (ca. 85%), while anthocyanins were the major free phenolic compounds. Among the different samples, bound phenolic extracts of corn appeared to have greater anti-radical and reducing activities than free phenolic extracts from the same grain samples when tested at a normalized phenolic concentration. The phenotypes Veracruz 42 and AREQ516540TL exhibited the greatest activities and these purple-colored strains were most enriched in anthocyanins. Extracts from a red-colored phenotype Pinto were also among the most effective at exhibiting anti-radical activities. Differences in free-radical scavenging and reducing activities appeared to be dependent on the unique profile of anthocyanins and other phenolics in each phenotype.