Rate and Equilibrium Constants for the Dehydration and Deprotonation Reactions of Some Monoacylated and Glycosylated Cyanidin Derivatives

• Published in: Journal of agricultural and food chemistry Vol. 47; no. 8; pp. 3449 - 3454
• Main Authors: Redus, Marc, Baker, David C, Dougall, Donald K
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-08-1999
• Subjects: anthocyanins; Anthocyanins - chemistry; Benzopyrans - chemistry; Biological and medical sciences; cell suspension culture; chemical reactions; Chemistry; color; cyanidin; Daucus carota; derivatives; Desiccation; Exact sciences and technology; Food additives; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; Heterocyclic compounds; Heterocyclic compounds with o, s, se, te hetero atom and condensed derivatives; Kinetics; Molecular Structure; Organic chemistry; Preparations and properties; Regression Analysis; Structure-Activity Relationship; Anthocyanin; Equilibrium constant; Biochemical analysis; Color; Glycosylation; Dehydration; Experimental study; Organic pigment; Acyl group; pH; Rate constant; Physicochemical properties; Acylation; Deprotonation
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf9813485

The rate and equilibrium constants for the pH-dependent hydration of a series of monoacylated anthocyanins semi-biosynthesized using a wild carrot suspension culture have been measured. The features of the acyl groups that decrease the hydration and thus decrease the loss of color of these anthocyanins are the presence of the side-chain double bond of the cinnamic acids and the presence of electron-donating substituents at the para-position of the acyl group. Methoxyl groups in the meta-position of the acyl groups have a greater effect than can be explained by their effects on the electron density in the acyl group. The data also suggest that there may be additional features of the acyl groups which contribute to the color retention in anthocyanins. Keywords: Anthocyanins; color stability; carrot (Daucus carota ssp. carota); flavylium ion hydration; pH effects