Variability in antioxidants in yellow, white, and red coloured maize grain in response to different fertilizers

Abstract

Maize (Zea mays L.) grain is an important source of nutrients in human diet. The differences in content and relations between certain components of maize grain impact grain colour and its nutritional quality. The objective of the Study was to examine effects of different fertilization systems: mineral fertilizer (urea), organic fertilizer, and bio-fertilizer on white, yellow, and red coloured maize hybrids, regarding grain yield and variations in content of antioxidants: phytate, phenolic compounds, glutathione, carotenoids (yellow pigment), and reduction capacity of DPPH radical. Two-fold higher average grain yield and double fold lower concentration of phenols and carotenoids were present in 2018, in comparison to drier 2017. The lowest phytate content and the highest values of phenols and DPPH reduction capacity were present in red maize kernel, as a hybrid with the highest yield, while in yellow maize kernel, the highest values of yellow pigment and glutathione occurred. The bio-fertilizer expressed the positive impact on reduction of phytate concentration and increase of phenols concentration in maize grain, while urea increased concentration of yellow pigment and glutathione. Correlation analysis showed that reduction in phytate and carotenoids was significant and positive related with grain yield increase, while phenols showed positive correlation with reduction capacity of DPPH radical. Thus, it was shown that changes in fertilization methods could affect antioxidants status in maize grain, particularly in red coloured maize, which besides high yield potential, possess remarkable higher antioxidant capacity in regard to yellow and white coloured maize.