Reaction’s mechanism of fresh apple juice enzymatic browning in the presence of maltosyl-β-cyclodextrin

Polyphenol oxidase causes enzymatic browning by catalyzing natural phenolic compounds to quinones. Subsequent nonenzymatic oxidative polymerization reactions form brown, black, or red pigments (melanins). Many methods can be shown experimentally to diminish or prevent browning but are not all applicable for food use. In this work, the colour of fresh apple juice was evaluated in the presence of maltosyl-β-CD, compound that complex polyphenol oxidases substrates. The effectiveness of CD as browning inhibitor was determined by the difference between the colours observed in the CD-treated sample and the controls, using the colour space CIE- L, a*, b* system. We have kinetically modelled apple juice enzymatic browning in the absence and presence of maltosyl-β-CD. The complexation constant between the mixtures of diphenols present in apple juice and maltosyl-β-CD was calculated (K_c = 4.09 mM⁻¹).