Study on the oxidation browning of cider during process

摘要

Experiments were performed to monitor the phenols , polyphenoloxidase (PPO) in seven apple cultures and the change in PPO during the cidermaking . PPO lies in the whole process , but play an important role in former period . The phenols in apple and ciders were analyzed with HPLC , and the result suggested that chlorogenic acid and epicatechin monomers and oligomers were the major phenols in apple , and responsible for the browning . Enzymatic and nonenzymatic oxidation were different to each other , but they were similar in some aspect. The oxidation browning of 2. 0mmol/L epicatechin was studied at pH6.5,25℃ in model system , and the enzymatic and nonenzymatic browning were compared from several aspect : other products was different except for the primary products; the reaction rate of enzymatic oxidation was 1000 times that of the nonenzymatic oxidation ; the browning degree of enzymatic oxidation was 1.5737/120min which is higher than that of nonenzymatic oxidation (0.4742/316h).