Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2018
Publication Date: 9/25/2018
Citation: Chatham, L.A., West, L., Berhow, M.A., Vermillion, K.E., Juvik, J.A. 2018. Unique flavanol-anthocyanin condensed forms in Apache red purple corn. Journal of Agricultural and Food Chemistry. 66:10844-10854.
DOI: https://doi.org/10.1021/acs.jafc.8b04723

Interpretive Summary: Pigments from corn are an economical yet natural substitute capable of replacing artificial red color dyes. However, all pigmented corn varieties examined to date primarily contain bluish-red or pink in their extracts. Here we describe the first deep red-dominant pigmented corn lines from the landrace Apache Red (AR). Extracts from these lines more closely resemble FD&C Red #40 compared other pigmented corn lines. Anthocyanins, the natural plant color compounds, were characterized from six corn families. From this, we identified two new anthocyanin color compounds. Additionally, several other natural plant phenolic compounds were identified in abundance. With a diverse natural product profile containing an array of different anthocyanin color species, the Apache Red corn line will be an important tool for studying the control of the color accumulation in corn seeds as well as a valuable source of genetics in future plant breeding programs aiming to replace FD&C Red #40 with natural colorants.

Technical Abstract: Anthocyanin pigments from corn pericarp are an economical yet natural substitute capable of replacing FD&C Red #40 (Allura Red AC). However, all pericarp pigmented corn varieties examined to date primarily contain cyanidin-derived anthocyanins, which produce bluish-red or pink extracts. Here we describe the first pelargonidin-dominant pericarp pigmented corn lines from the landrace Apache Red (AR). Extracts from these lines more closely resemble FD&C Red #40 compared to cyanidin dominant lines. Anthocyanins were characterized from six AR families using HPLC-MS. From this, we identified two new flavanol-anthocyanin condensed forms in corn: epi(catechin)-(4,8)-pelargonidin-3,5 diglucoside and epi(afzelechin)-(4,8)-pelargonidin-3,5 diglucoside, which were subsequently confirmed with NMR. To our knowledge, both of these compounds are previously unreported in corn. Additionally, several C-glycosyl flavones were identified in abundance. With a diverse flavonoid profile containing an array of different anthocyanin species and flavones, Apache Red will be an important line in which to study control of the flavonoid biosynthesis pathway as well as a valuable source of genetics in future plant breeding programs aiming to replace FD&C Red #40 with natural colorants.