Abstract
Red radish anthocyanins are relatively stable due to the acylation of anthocyanins with organic and phenolic acid moieties. The objective of this study was to create and identify a novel ethyl-bridged acylated anthocyanin with a stable violet color from red radishes in the presence of acetaldehyde and catechin. After incubation at ambient temperature for one week at 21 °C the reaction mixture with acetaldehyde and catechin turned from bright red to a vivid purple color. The newly formed compounds were tentatively identified with liquid chromatography-electrospray ionization-mass spectrometry. Color stability (CIE L*C*h) was monitored over six months at 21 °C and anthocyanin stability was evaluated by HPLC. Next, radishes were fermented by Zymomonas mobilis, a high acetaldehyde producing bacteria. Natural sources of catechin were used to replace the catechin standard, but the same purple color did not appear with the addition of cocoa powder or fava beans. The ethyliden-bridged radish anthocyanins possess excellent color stability and could serve as a natural food colorant.
Highlights
Anthocyanins are an obvious candidate to replace artificial dyes in the food industry, but these natural colorants currently have stability issues
Red radishes were used in this study since their pigments were previously reported to have comparable color properties to FD&C Red No 40 and function as a natural replacement in maraschino cherries [10]
We propose the ethyl-bridged catechin is attached to the anthocyanin via C-8, it is possible to attach at C-6 as well
Summary
Anthocyanins are an obvious candidate to replace artificial dyes in the food industry, but these natural colorants currently have stability issues. Using anthocyanins from natural sources allows a cleaner product label by removing artificial colorants from the label. Some potential sources of anthocyanins include berries, red cabbage, eggplant, and radishes. Adding one of these to a label can deliver the appeal of an ingredient over an additive [2]. Yellow xanthylium ion compounds are formed in wine, but the more significant products were violet [3]. Reddish-blue enantiomers of malvidin-3-glucoside (the main anthocyanin in wine) with an ethyl linkage to procyanidin B2 catalyzed by acetaldehyde were reported [4], but violet compounds were noted. Acetaldehyde is formed through fermentation and via the oxidation of ethanol
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
