Pigmented flower extracts of plant species from the Geraniaceae and Lamiaceae families as natural food colourants: anthocyanin composition, thermal and oxidative stability

Abstract

Summary This study determined the anthocyanin profile of pigmented flower extracts from some Geraniaceae and Lamiaceae plant species found in South Africa, and their thermal and oxidative stability to assess their potential food application. Anthocyanins in the Geraniaceae (Pelargonium grandiflorum Willd. and Pelargonium × hortorum L.H. Bailey, Pelargonium zonale hybrid) were 3,5‐diglucosides of delphinidin, petunidin, pelargonidin, peonidin and malvidin and acetyl‐acylated malvidin, delphinidin and petunidin. The Lamiaceae species (Salvia aurea × dolomitica Bae’s blue, Salvia dolomitica Codd and Plectranthus zuluensis T. Cooke) mainly contained rutinosides of pelargonidin, glucosides of petunidin, pelargonidin and p‐coumaric acid‐ and malonyl‐acylated delphinidin and malvidin. Lamiaceae pigments had higher thermal and oxidative stability. This could be due to aromatic malonyl‐acylated anthocyanin self‐association and strong intermolecular interactions with phenolic acids and derivatives. Flowers from Lamiaceae and Geraniaceae have potential application as natural food colourants, but temperature and oxidising conditions must be considered depending on the particular species being used.

Acylation of Anthocyanins and Their Applications in the Food Industry: Mechanisms and Recent Research Advances

“…The results showed that acylated anthocyanins, which contain diacylated and disaccharide groups of paeoniflorin derivatives, were more stable than other anthocyanins during storage, with much lower rates of anthocyanin degradation after 6 months of storage. Similarly, acylated anthocyanins extracted by Venter et al [ 81 ] from plants of the Geraniaceae and Lamiaceae families remained stable over a wide temperature range, and these results suggest that Geraniaceae and Lamiaceae families have better potential applications as natural food colourants.…”

Evaluation of the biological responses of silver nanoparticles synthesized using Pelargonium x hortorum extract

“…Thus, it has been reported the presence of the alkaloids elaeocarpidine and its 20-H isomer epieiaeocarpidine by Dragendorff's reaction; 41,42 tanins, flavonoids, sesquiterpenes, phenolic acids, cinnamic acids, coumarins and monoterpenes by GC-MS; 43 and polyphenols and flavonoids measured using the Folin-Ciocalteu and ammonium chloride methods, and terpenoids by GC-MS 44 analysis in the leaves of the plant; anacardin acids in the trichome exudate of the plant; 45 gallic acid and catechin in the roots and flowers; 46 and anthocyanins pelargonidin glucoside derivative, peonidin glucoside derivative, cyanidin-3,5-diglucoside, petunidin-3- O -(6-acetyl)-5- O -diglucoside, malvidin-3- O -(6- O -acetyl)-5- O -diglucoside, peonidin-3, 5- O -diglucoside, and malvidin-3,5- O -diglucoside determined by UPLC-MS in flowers. 47…”