Phytochemicals and antioxidant capacity in four Italian traditional maize (Zea mays L.) varieties

Abstract

Flours of four pigmented (from orange to red and dark red) local Italian corns, studied for their soluble, soluble conjugate, and insoluble-bound phenols and flavonoids, showed a prevalence of the insoluble-bound fraction (70–80%). Correlations were found between the flours antioxidant capacity, measured with CUPRAC, FRAP, and DPPH methods, and soluble phenols and flavonoids content. A correlation was also found between ascorbic acid content and flours antioxidant power. Anthocyanins were present in small amounts in the red/dark red seeds; however, acid-alcohol assays and spectral analyses of pericarp extracts indicated the presence of red-brick phlobaphenes in these varieties. Spectrophotometrically quantified total carotenoids were significantly higher in one of the local varieties (Nano); RP-HPLC analyses indicated that the local varieties contained significantly higher amounts of zeaxanthin and β-carotene, and lower amounts of lutein, than a commercial line. Among local varieties, Nano expressed the highest levels of zeaxanthin, β-carotene, and β-cryptoxanthin.

Keywords:

• Antioxidant capacity
• ascorbic acid
• carotenoids
• phenolics
• phlobaphenes
• traditional variety; Zea mays L.

Acknowledgements

The authors wish to thank Dr. Fabiana Fiorani at the Tuscany Region Germplasm Bank (section Centro la Piana, Camporgiano, LU, Italy) and the Comunità Montana della Mediavalle del Serchio (LU, Italy), for kindly supplying us with the maize varieties seeds.

Disclosure statement

The authors report no conflicts of interest.