Red and blue colors in maize kernel are the consequence of anthocyanin pigments, responsible for the increased phenolic content and antioxidant activity in maize. Therefore, interest in pigmented maize as a novel functional food due to its possible health benefits and unique taste has grown. The red color in maize kernel originates from pericarp and is maternally inherited while the blue color originates from aleurone, which is triploid in nature and its mode of inheritance is more complicated. Red and blue maize are usually low-yielding populations, and at the Maize Research Institute Zemun Polje (MRIZP), commercial inbred lines have been converted to red and blue colors to produce high-yielding red and blue maize hybrids.
Maize extractable phenolic content (EPC) can be directly determined through wet chemistry and measures phenolic amides, glycerides, free phenolic acids, and some flavonoids. In this study, however, Fourier-transformed near-infrared reflectance spectroscopy (FT-NIRS), as a non-destructive, inexpensive, and rapid technique has been used to scan EPC profiles of 56 MRIZP maize samples (14 genotypes in two replications and two environments) differing in kernel color: yellow, red pericarp, blue aleurone and red pericarp with blue aleurone. Twenty samples with outlying EPC values have been directly analyzed for total phenolics and these values have been used to adjust and improve NIRS calibration.
EPC values ranged from 1.69 to 6.82 mg g-1 across genotypes and environments. Two red inbred lines had the highest EPC content in 2017, 6.82 and 5.11 mg g-1, and, overall samples from 2017 had a higher content of EPC compared to the same genotypes grown in 2018. Red genotypes on average had the highest EPC content, followed by red-blue, while yellow and blue kernels had similar and the lowest content within the samples
