Comparing the Chemistry of Malvidin-3-O-glucoside and Malvidin-3,5-O-diglucoside Networks: A Holistic Approach to the Acidic and Basic Paradigms with Implications in Biological Studies

• Type: Article in International Scientific Journal
• Date: 2024

Authors

Seco, A (Author) Other; Pereira, AR (Author) Other; Camuenho, A (Author) Other; Oliveira, J (Author) Other; Dias, R (Author) Other; Brás, NF (Author) Other; Basílio, N (Author) Other; Parola, AJ (Author) Other; Lima, JC (Author) Other; Victor de Freitas (Author) FCUP; Pina, F (Author) Other

Journal

Title: Journal of Agricultural and Food Chemistry

Vol. 72

Pages: 7497-7510

ISSN: 0021-8561

Publisher: American Chemical Society

Indexing

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Other information

Authenticus ID: P-010-85Y

DOI: 10.1021/acs.jafc.4c00552

Abstract (EN): The kinetics, thermodynamics, and degradation of malvidin mono- and diglucosides were studied following a holistic approach by extending to the basic medium. In acidic conditions, the reversible kinetics of the flavylium cation toward the equilibrium is controlled by the hydration and cis-trans isomerization steps, while in the basic medium, the OH- nucleophilic addition to the anionic quinoidal bases is the slowest step. There is a pH range (transition pHs), between the acidic and basic paradigms, that includes physiological pH (7.4), where degradation reactions occur faster, preventing the system from reaching the equilibrium. The transition pH of the diglucoside is narrower, and in contrast with the monoglucoside, there is no evidence for the formation of colored oligomers among the degradation products. Noteworthy, OH- addition in position 4 to form B42-, a kinetic product that decreases the overall equilibration rate, was observed only for the diglucoside.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14