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Stereochemistry and glycosidic linkages of C3-glycosylations affected the reactivity of cyanidin derivatives

Author:
Farr, Jacob E., Sigurdson, Gregory T., Giusti, M. Mónica
Source:
Food chemistry 2019 v.278 pp. 443-451
ISSN:
0308-8146
Subject:
anthocyanins, ascorbic acid, bisulfites, bleaching, cyanidin, disaccharides, glycosidic linkages, glycosylation, half life, high performance liquid chromatography, monosaccharides, pH, stereochemistry
Abstract:
The impact of glycosylation on anthocyanin stability has largely been associated with sugar type, site, and size, with glycosyl stereochemistry being under-explored. Seven cyanidin-3-glycosides were isolated by HPLC, diluted in pH 1–9, mixed with bisulfite or ascorbic acid at pH 3, and stored for 8 weeks (25 °C, dark). Spectral changes, half-lives, and bleaching rates were determined. Cyanidin-3-galactoside was more reactive (susceptible to hydration and bleaching) than cyanidin-3-glucoside. The 1 → 2 disaccharides exhibited greater λvis-max (≤16 nm), resistance to hydration, and bleaching compared to 1 → 6 disaccharides.The 1 → 6 disaccharides had similar λvis-max (∼2 nm) to the monosaccharides but slightly improved resistance to hydration and bleaching. The tri-glycosylated anthocyanin had the greatest stability and its spectral and bleaching characteristics was intermediate to 1 → 2 and 1 → 6 disaccharides. The 1 → 2 disaccharides generally exhibited lower half-lives compared to monosaccharides; whereas, 1 → 6 disaccharides exhibited higher stability. These findings highlight the role of glycosyl assembly on anthocyanin reactivity and stability.
Agid:
6236999