Molar Absorptivity and Color Characteristics of Acylated and Non-Acylated Pelargonidin-Based Anthocyanins

• Published in: Journal of agricultural and food chemistry 1999-11, Vol.47 (11), p.4631-4637
• Main Authors: Giusti, M. Mónica, Rodríguez-Saona, Luis E, Wrolstad, Ronald E
• Format: Article
• Language: English
• Subjects: absorbance; Acylation; Analytical, structural and metabolic biochemistry; anthocyanins; Anthocyanins - chemistry; Biological and medical sciences; chemical reactions; cinnamic acid; color; derivatives; ferulic acid; Flavonoids - chemistry; Fundamental and applied biological sciences. Psychology; Glycosylation; Heterocyclic compounds, pigments; malonic acid; Miscellaneous; Other biological molecules; p-coumaric acid; pelargonidin; Pigments, Biological - chemistry; plant pigments; potatoes; radishes; raphanusin; Solvents; spectral analysis; Spectrophotometry, Ultraviolet; strawberries
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf981271k

The effects of glycosylation and acylation on the spectral characteristics, molar absorptivity, and color attributes of purified acylated and non-acylated pelargonidin derivatives were compared. Pigments were obtained from strawberries, radishes, red-fleshed potatoes, and partially hydrolyzed radish pigments. Individual pigments were isolated by using semipreparative HPLC. Spectral and color (CIEL*ch) attributes of purified pigments were measured. Molar absorptivity ranged from 15 600 to 39 590 for pelargonidin-3-glucoside (pg-3-glu) and pg-3-rutinoside-5-glucoside acylated with p-coumaric acid, respectively. The presence of cinnamic acid acylation had a considerable impact on spectral and color characteristics, causing a bathochromic shift of λmax. Sugar substitution also played an important role, with a hypsochromic shift caused by the presence of glycosylation. Pg-3,5-diglu and pg-3,5-triglu possessed a higher hue angle (>40°) than the other pg derivatives at pH 1.0, corresponding to the yellow-orange region of the color solid. Acylation with malonic acid did not affect λmax and showed little effect on color characteristics. The solvent system had an effect not only on the molar absorptivity, but also on the visual color characteristic of the pigments. Keywords: Pelargonidin derivatives; acylation; molar absorptivity; color