Ascorbic acid and 4-hexylresorcinol effects on pear PPO and PPO catalyzed browning reaction.
The effects of ascorbic acid (AA) and 4-hexylresorcinol (4-HR) on pear polyphenoloxidase (PPO) activity and stability have been investigated in vitro. AA does not interact directly with PPO but prevents browning by reducing oxidized substrates. The 4-HR exerts a dual role on PPO. If no substrates are present, it interacts preferably with the deoxy form of PPO inactivating it. If substrates and 4-HR are both present they compete for the catalytic site. The 4-HR behaves then as a canonical enzyme inhibitor, binding to the met form of PPO. Simultaneous addition of 4-HR and AA has synergistic inhibition or inactivatory effects depending on the presence or the absence of PPO substrates.
Arias
E
E
Grupo de Investigación en Alimentos de Origen Vegetal, Facultad de Veterinaria, Univ. Zaragoza, C/Miguel Servet, 177, 50013, Zaragoza, Spain.
González
J
J
Oria
R
R
Lopez-Buesa
P
P
D001205:Ascorbic Acid / Q000494:pharmacology*; D004156:Catechol Oxidase / Q000037:antagonists & inhibitors*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006604:Hexylresorcinol / Q000494:pharmacology*; D015416:Maillard Reaction / Q000187:drug effects; D031989:Pyrus / Q000201:enzymology*; D013379:Substrate Specificity
D004791:Enzyme Inhibitors; D004156:Catechol Oxidase; D001205:Ascorbic Acid; D006604:Hexylresorcinol