文摘
The degradation mechanism of cyanidin 3-rutinoside in the presence of (−)-epicatechin and litchi pericarp polyphenol oxidase (PPO) was investigated using several model systems. The enzymically generated (−)-epicatechin o-quinone could induce cyanidin 3-rutinoside degradation. The results obtained in this study allowed us to propose a pathway for cyanidin 3-rutinoside degradation in the presence of (−)-epicatechin and litchi pericarp PPO. First, enzymatic oxidation of (−)-epicatechin produced the corresponding o-quinone, and then cyanidin 3-rutinoside and (−)-epicatechin competed for (−)-epicatechin o-quinone, resulting in degradation of cyanidin 3-rutinoside and regeneration of (−)-epicatechin. Moreover, the results of kinetic studies indicated this competition was influenced by both (−)-epicatechin concentration and cyanidin 3-rutinoside concentration in the model system.