Biochemical Profile of Leaf, Silk and Grain Samples of Eight Maize Landraces (Z ea mays L.) Cultivated in Two Low-Input Agricultural Systems

Abstract

Highlights We analyzed total carotenoids, anthocyanins and phenolic acids in grains, leaves and silks of maize landraces. Higher amounts of secondary metabolites were found in leaves and silks. High performance liquid chromatography revealed the xanthophylls lutein and zeaxanthin as the major carotenoids in grains. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of crude extracts showed a higher richness of anthocyanin in leaf samples than in silks. Abstract This research aimed to determine the biochemical profile of leaf, silk and grain samples of eight maize landraces (Zea mays L.) cultivated in southern Brazil. To accomplish this, reverse-phase high performance liquid chromatography-UV-visible (RP-HPLC-UV-vis), UV-vis spectrophotometry, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and chemometrics were used to examine carotenoids and their isomers, anthocyanin and phenolic acids. Leaf tissue samples showed higher amounts of carotenoids (838.6 μg/g – Língua de Papagaio variety), anthocyanins (405.8 μg/g – Palha Roxa variety) and phenolics (655.0 μg/g – Roxo variety), followed by maize silks and grains. RP-HPLC-UV-vis analysis of grain extracts revealed xanthophylls lutein and zeaxanthin as the major compounds. The anthocyanin profile by MALDI-TOF MS identified pelargonidin, cyanidin, peonidin, malvidin and glucoside derivatives in leaf extracts, and silk samples were shown to contain cyanidin, peonidin and 7-methoxy-apigeninidin glucoside. These findings indicate that the discarded material, i.e., leaves and silks, can be prospected as bioactive biomasses useful to industrial sectors. Practical Applications The present study indicates that leaves and silks of maize landraces, typically discarded in the normal process of agricultural production, can be prospected in food systems as potential sources of antioxidant compounds, such as carotenoids, anthocyanins and phenolics. Moreover, acquisition of these raw materials for development of new products in the pharmaceutical, food and cosmetics industries can be accomplished with no or negligible cost. Thus, the preservation of this valuable germplasm is to be encouraged, as it will increase the possibility of economic return to small farmers.