Variation of Kernel Anthocyanin and Carotenoid Pigment Content in USA/Mexico Borderland Land Races of Maize

Abstract

Variation of Kernel Anthocyanin and Carotenoid Pigment Content in USA/Mexico Borderland Land Races of Maize. Maize is the only major cereal crop that displays abundant variation for health-promoting carotenoid and anthocyanin pigments. Traditional farmers in the USA/Mexico Borderland region utilize many land race varieties with diverse kernel characteristics reflecting enculturated preferences, including color. Food prepared using these varieties may provide benefits to human health, but the kernel pigment content, and grain physical and compositional traits, have not been characterized. Seed from 48 diverse accessions representing 18 races of maize originating from the Borderland region were obtained from Native Seeds/SEARCH and planted in replicated nurseries at two locations (Ohio and Arizona) in 2008. We visually determined kernel color and quantified total carotenoid and anthocyanin pigment content of samples obtained from these nurseries using spectrophotometric analysis. Nonpigmented (white) followed by yellow kernel colors were most abundant. Populations with high carotenoid pigment content (i.e., above 40 μg/g) were not observed, whereas many accessions produced ears with mixtures of red, purple, and blue kernels containing anthocyanin pigments. A wide range in anthocyanin pigment content was observed across and within populations—some kernels displayed concentrations above 50 mg/100 g. Kernel hardness was determined visually, and protein and oil content were determined by near-infrared spectrometric analysis. Flinty (hard) followed by floury (soft) kernel types were most abundant. Carotenoid content was highest in orange- and yellow-colored pop-type kernels. Anthocyanin content was highest in blue- and purple-colored floury and flint-type kernels. Kernel weight, protein, oil, and carotenoid content were significantly affected by location. Preservation of culturally-adapted varieties with diverse kernel pigments is important not only because of their genetic diversity—they also may contribute to enhanced human health and nutrition.