Abstract
Biofortified maize is not only a good vehicle for provitamin A carotenoids for vitamin A deficient populations in developing countries but also a source of vitamin E, tocochromanols and phenolic compounds, which have antioxidant properties. Using high-performance liquid chromatography and a total antioxidant performance assay, the present study analyzed the antioxidant variation and antioxidant activity of 36 provitamin A improved maize hybrids and one common yellow maize hybrid. The ranges of major carotenoids in provitamin A carotenoids biofortified maize were zeaxanthin [1.2-13.2 µg g-1 dry weight (DW)], β-cryptoxanthin (1.3-8.8 µg g-1 DW) and β-carotene (1.3-8.0 µg g-1 DW). The ranges of vitamin E compounds identified in provitamin A carotenoids biofortified maize were α-tocopherol (3.4-34.3 µg g-1 DW), γ-tocopherol (5.9-54.4 µg g-1 DW), α-tocotrienol (2.6-19.5 µg g-1 DW) and γ-tocotrienol (45.4 µg g-1 DW). The ranges of phenolic compounds were γ-oryzanol (0.0-0.8 mg g-1 DW), ferulic acid (0.4-3.6 mg g-1 DW) and p-coumaric acid (0.1-0.45 mg g-1 DW). There was significant correlation between α-tocopherol and cis isomers of β-carotene (P < 0.01). Tocotrienols were correlated with α-tocopherol and γ-oryzanol (P < 0.01). Conclusion, genotype was significant in determining the variation in β-cryptoxanthin, β-carotene, α-tocopherol and γ-tocopherol contents (P < 0.01). A genotype × environment interaction was observed for γ-tocopherol content (P < 0.01).