Diversity in Phytochemical Composition and Antioxidant Capacity of Dent, Flint, and Specialty Corns

ABSTRACT Dent, flint, and specialty genotypes of Indian yellow maize were evaluated for phytochemical content and their hydrophilic antioxidant capacity. Solid‐phase extraction coupled with solid–liquid extraction was used to obtain free phenolics and flavonoids from maize samples, reducing the use of excessive solvents and handling time. Bound phenolics were extracted with enhanced acidic hydrolysis to improve extractability. The phenolic contents in Indian maize genotypes ranged from 46 to 79 μmol of ferulic acid equivalents per gram of sample on a dry basis (db). Carotenoids in Indian maize genotypes were found to be equivalent to Chinese yellow maize and ranged from 13 to 24 μg/g of sample (db), whereas tocol content varied greatly in the range of 607–1,238 μg of α‐tocopherol equivalents/g of sample (db). Dent and flint corn did not exhibit differences ( P > 0.05) in their phenolic contents, whereas among the specialty genotypes sweet corn contained the highest phenolics but least carotenoids ( P < 0.05). Bound extracts appeared to contribute largely to 2,2′‐diphenyl‐1‐picrylhydrazyl free radical scavenging, hydrogen peroxide scavenging, and ferric reducing antioxidant power of maize genotypes. Sweet corn exhibited higher antioxidant capacity ( P < 0.05) among all the genotypes. The antioxidant capacities correlated well with the total phenolic contents of the maize genotypes.