Chromatic, Nutritional and Nutraceutical Properties of Pigmented Native Maize (Zea mays L.) Genotypes from the Northeast of Mexico

The aim of this study was the characterization of chromatic, nutritional and nutraceutical properties of fifteen native maize genotypes of the races: conico norteno, elotes conicos, raton, conico norteno × elotes conicos, raton × elotes conicos, Celaya × elotes conicos, elotes conicos × conico norteno from the northeast of Mexico. The results showed that the values of the color parameters L*, C* and h in genotypes range from 25.13 to 63.64, 2.41 to 33.58 and 14.36 to 359.19, respectively. The percentage of nutritional component varied from carbohydrates (71.30–74.88), protein (9.72–12.57) and moisture (7.98–9.67). The samples were rich in P, K, Mg, Zn and Fe. The total phenols content (free + bound) ranged from 349.39 to 485.71 mgGAE/100 g, showing bound fractions higher content than free fractions. The total flavonoids (free + bound) were from 24.00 to 105.75 mgCE/100 g, and for eight of the genotypes the bound fractions were higher than free fractions. Condensed tannins were only found in free fractions with values ranging from 33.70 to 158.55 mgCE/100 g. Total anthocyanins ranged from 1.38 to 74.52 mgC3GE/100 g. In HPLC analysis, ferulic acid (103.34–164.90 mg/100 g) was the main phenolic compound followed by coumaric acid (5.57–15.52 mg/100 g) and they were only identified in bound extracts. Finally, the antioxidant capacity (free + bound) expressed in µmolTE/100 g was from 1127.70 to 1875.70, 2826.90 to 4263.90, 730.94 to 1340.65 and 3484.80 to 5592.60 in DPPH, ABTS, FRAP and ORAC, respectively, and IC50 to DPPH and ABTS were expressed in mg/mL. In conclusion, significant correlation was found between chromatic versus antioxidant capacity, and anthocyanin content. In addition, higher phenolic content were found in bound extracts, and a genetic diversity was observed between maize genotypes.