Camuenho, AmbrósioSeco, AndréParola, A. JorgeBasílio, NunoPina, Fernando2022-11-082022-11-082022-07-262470-1343PURE: 46200701PURE UUID: 6577a72f-7cb4-4c82-99e5-3787598b8bc3Scopus: 85135223935WOS: 000829558000001PubMed: 35910157PubMedCentral: PMC9330165ORCID: /0000-0001-8529-6848/work/122411393ORCID: /0000-0002-1333-9076/work/122411510http://hdl.handle.net/10362/145316no 219201Intermolecular copigmentation of malvidin-3-O-glucoside with caffeine was studied using a holistic procedure that includes the extension to basic pH values. In moderately basic solutions (7.5 < pH < 9.5) and independently of the copigment presence, there is a pH region where degradation of the quinoidal base and anionic quinoidal bases is faster than hydration and OH-nucleophilic addition, preventing the system from reaching the equilibrium. Intermolecular copigmentation with caffeine reduces significantly the degradation rate of quinoidal bases. In a more basic medium, the equilibrium is reached and degradation occurs from the anionic chalcones. In this case, the addition of caffeine also reduces the degradation rate in the interval 10 < pH < 11.5.82630948engMalvidinAnthocyaninsPigmentsGeneral ChemistryGeneral Chemical Engineeringjournal article10.1021/acsomega.2c02571https://www.scopus.com/pages/publications/85135223935