Primary and Phenolic Metabolites Analyses, In Vitro Health-Relevant Bioactivity and Physical Characteristics of Purple Corn (Zea mays L.) Grown at Two Andean Geographical Locations.

Lena Gálvez Ranilla,Romina Pedreschi,Claudia Fuentealba,Kalidas Shetty,Briggite Anyela Rios-Gonzales,María Fernanda Ramírez-Pinto

doi:10.3390/metabo11110722

Abstract

Purple corn (Zea mays L.) is native to the Andean region, but limited research has been performed about the potential metabolic variability when grown under Andean environmental conditions. This study was aimed at evaluating the phenolic and primary polar metabolites composition of purple corn (kernels and cobs) grown at two Peruvian Andean locations (lowland and highland) using targeted UHPLC (ultra-high-performance liquid chromatography) and untargeted GC-MS (gas chromatography mass spectrometry) metabolomic platforms, respectively. Changes in the physical characteristics and the in vitro bioactivity were also determined. Purple corn from the highland zone showed higher contents of ash, crude fiber, total phenolic contents, DPPH (2,2-diphenyl-1-picrylhydrazyl) antioxidant capacity, and α-amylase inhibitory activity in kernels, whereas increased levels of flavonoids (anthocyanins and quercetin derivatives) and ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] antioxidant capacity were observed in cobs in comparison to lowland samples. No effect of the Andean location was found on the α-glucosidase inhibitory activity relevant for hyperglycemia management, while yield-linked physical characteristics were high in purple corn grown at the lowland zone. Polar primary metabolites related to the carbohydrate (monosaccharides, sucrose, and d-sorbitol), amino acid (valine and alanine), and tricarboxylic acid cycle (succinic, fumaric, and aconitic acid) metabolism were higher in highland purple corn (cob and kernel) likely due to abiotic stress factors from the highland environment. This study provides the foundation for further breeding improvements at Andean locations.

Highlights

IntroductionPurple corn (Zea mays L.) is an amylaceous and purple-pigmented corn that belongs to the Peruvian race Kculli, which means “black” in the “Quechua” native language [1]
Purple corn grown at two Peruvian Andean locations showed differences in the primary and secondary metabolite composition, the in vitro healthrelevant functional quality, and some physical characteristics
Purple corn kernels from plants cultivated at the highland zone had higher contents of ash, crude fiber, total phenolic contents, bound ferulic acid, DPPH total antioxidant capacity, and α-amylase inhibitory activities, whereas cobs showed increased levels of flavonoids, and ABTS total antioxidant capacity than lowland samples

Summary

Introduction

Purple corn (Zea mays L.) is an amylaceous and purple-pigmented corn that belongs to the Peruvian race Kculli, which means “black” in the “Quechua” native language [1]. This race was derived from the highland pre-Columbian proto-Kculli race, which appeared in the final preceramic period in Peru (~4000 calibrated years before the present) and has become an important staple cereal food among indigenous communities from the Andean region in South America, including Peru, Ecuador, Bolivia, and Argentina [2,3]. Other non-anthocyanin phenolic metabolites such as different flavonoids and phenolic acids have been confirmed in Andean purple corn [8,9,10] Due to this high phenolic metabolite composition, purple corn has been linked to health-relevant bioactive properties. The antihypertensive effect of purple corn has been demonstrated in a clinical study [15]

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