Biofortification of maize grain with zinc oxide nanoparticles and its relationship with agronomic and phytochemical quality

Abstract

Maize is a high-demand staple crop valued for both its nutritional and phytochemical qualities, yet it is deficient in Zn. Nanobiofortification is a promising strategy to increase Zn content. A completely randomized block experiment was conducted in Venecia, Durango, México (25°46′56″ N, 103°21′02″ W) to evaluate five zinc oxide nanoparticle treatments (control; T1: 100 mg.L⁻¹; T2: 200 mg.L⁻¹; T3: 300 mg.L⁻¹; T4: 400 mg.L⁻¹) and their effects on the nutritional, agronomic, and phytochemical quality of maize grain. No significant differences were observed in ear diameter, row number, grains per row, or ear mass, whereas ear length and 1,000 grain mass differed significantly. Overall, T1 showed the highest morphometric values, while enzymatic activity increased significantly in biofortified grains. Proximate analysis showed that T3 and T4 had higher ash, neutral detergent fiber, and fat contents than the control. Nanoparticle treatments also increased flavonoid and phenol contents, antioxidant capacity, and enzymatic activity. Zn concentration in T4 grains was 26 % higher than in the control. These findings indicate that ZnO nanoparticles enhance the phytochemical and nutritional quality of maize grains and represent an effective biofortification strategy, although agronomic quality was not consistently improved.