title: Effect of glucuronosylation on anthocyanin color stability.
abstract: The effect of glucuronosylation on the color stability of anthocyanins was investigated using glucuronosylated anthocyanins isolated from the flower petals of the red daisy (Bellis perennis) or obtained by enzymatic in vitro synthesis using heterologously expressed red daisy glucuronosyltransferase BpUGT94B1. Color stability toward light and heat stress was assessed by monitoring CIELAB color coordinates and stability at pH 7.0 by A(550). Cyanidin-3-O-2''-O-glucuronosylglucoside showed improved color stability in response to light compared to both cyanidin 3-O-glucoside and cyanidin 3-O-2''-O-diglucoside. A similar increase in color stability was not observed following heat treatment. Glucuronosylation did not increase the stability of anthocyanins at pH 7.0 as determined by A(550). To test for a possible effect of glucuronosylation on the color stability of anthocyanins in plant extracts used for food coloration, an elderberry (Sambucus nigra) extract was glucuronosylated in vitro. Glucuronosylation of approximately 50% of total anthocyanins proceeded fast and resulted in increased color stability in response to both heat and light. The data show that glucuronosylation may be used to stabilize industrially used extracts of natural colorants.
authors.affiliation: Department of Plant Biology and Biotechnology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Sarah Anne
authors.initials: SA
authors.lastname: Osmani
authors.forename: Esben Halkjaer
authors.initials: EH
authors.lastname: Hansen
authors.forename: Céline
authors.initials: C
authors.lastname: Malien-Aubert
authors.forename: Carl-Erik
authors.initials: CE
authors.lastname: Olsen
authors.forename: Søren
authors.initials: S
authors.lastname: Bak
authors.forename: Birger Lindberg
authors.initials: BL
authors.lastname: Møller
mesh_terms: D000872:Anthocyanins / Q000737:chemistry* / Q000378:metabolism*; D019659:Asteraceae / Q000737:chemistry / Q000201:enzymology; D003116:Color; D004355:Drug Stability; D035264:Flowers / Q000737:chemistry / Q000201:enzymology; D005505:Food Coloring Agents / Q000737:chemistry; D014453:Glucuronosyltransferase / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D008027:Light; D011994:Recombinant Proteins / Q000378:metabolism; D027923:Sambucus / Q000737:chemistry
chemical_list: D000872:Anthocyanins; D005505:Food Coloring Agents; D011994:Recombinant Proteins; D014453:Glucuronosyltransferase