Like many fruits, pineapples can turn brown once they are cut open and their flesh is exposed to the air. Even if you seal them in a container before refrigerating, the colour change can still take place due to oxidation -- the reaction of the fruit's enzymes to the oxygen it was exposed to once cut. Fortunately, you can give cut pineapple a special bath to coat it and protect it from turning an unappetising brown.
Pour the cool water into a bowl and add the fresh lemon juice. Stir the water and lemon juice together to mix.
Place the pieces of pineapple in the lemon juice and water mixture and soak for approximately 10 minutes.
Drain the bowl and remove the pieces of pineapple. Place them on a clean surface and pat dry with a clean, lint-free towel. Serve immediately or store in the fridge for two to four days in a container with a well-sealing lid.
You can also crush a vitamin C tablet and add it to 4.5 litres (1 gallon) of water as an alternative to water and lemon juice.
Avoid soaking the pineapple in the lemon water for more than 10 minutes to prevent it from taking on a lemony flavour.