The effectiveness of pineapple juice in enzymatic browning inhibition was evaluated on the cut surface
of banana slices. After storage of banana slices at 15 °C for 3 days, pineapple juice showed browning
inhibition to a similar extent as 8 mM ascorbic acid but less than 4 mM sodium metabisulfite.
Fractionation of pineapple juice by a solid-phase C18 cartridge revealed that the directly eluted fraction
(DE fraction) inhibited banana polyphenol oxidase (PPO) about 100% when compared to the control.
The DE fraction also showed more inhibitory effect than 8 mM ascorbic acid in enzymatic browning
inhibition of banana puree during storage at 5 °C for 24 h. Further identification of the DE fraction by
fractionation with ion exchange chromatography and confirmation using model systems indicated
that malic acid and citric acid play an important role in the enzymatic browning inhibition of banana
PPO.