Peach polyphenol oxidase inhibition by ?°??????-cyclodextrin and 4-hexylresorcinol is substrate dependent La inhibici???3n de la polifenoloxidasa de durazno por ?°??????-ciclodextrina y 4-hexilresorcinol es dependiente del sustrato

摘要

Polyphenol oxidase (PPO) was extracted from whole peaches and its catecholase activity was studied spectrophotometrically against three substrates: catechol (Cat), 4-methyl catechol (4MC), and chlorogenic acid (CA). Peach PPO specificity was: CA????>????4MC ?￠???? Cat. 4-hexylresorcinol (4HR, 0.5????mM) inhibited oxidation of Cat and CA by 50% or more, at all substrate concentrations, but had no effect on the oxidation of 4MC, suggesting that laccase-like activity was present in the extract. ???2-cyclodextrin (???2-CD, 10????mM) inhibited only CA oxidation and this effect was not abolished when free substrate concentrations were calculated suggesting a mechanism, additional to substrate complexation, in ???2-CD action. Combination of 4HR and ???2-CD had only a weak inhibitory effect on CA oxidation. In conclusion, ???2-CD and specially 4HR could be used as browning inhibitors in peach products and also as tools for studying different phenol oxidases. Combination of both compounds is not recommended for peaches.