How can I keep chopped fruit fresh for 2-3 hours?

Question

I need to cut up a large amount of fruit for use in a pavlova dessert tomorrow night - although the same question would no doubt apply to a fruit salad or other fresh fruit item.

Anyway, I won't have time to do this between dinner and dessert, so I'll need to prepare the fruit a few hours in advance, and I'd like to keep it looking and tasting super-fresh.

What can I do to preserve the appearance, texture, and flavour of the fruit for as long as possible after it's been cut up?

The fruits in question are apples, kiwis, and possibly a few bananas. I'd also be interested in knowing how to preserve strawberries, raspberries, and similar items.

I'd especially appreciate a complete breakdown of the process, i.e. is the freshness after a few hours going to be affected by how it's cut, storage vessels, air flow, temperatures, etc.?

Answer

I've preserved cut fruit for at least 6 hours before using just lemon juice. Lemon juice inhibits the oxidation of the fruit which prevents browning as well of a loss of crispness.

One lemon should be enough juice for a 1.5 quart bowl of cut fruit. Simply squeeze it over the fruit and toss gently to prevent bruising.

Since you'll be working with apples, kiwis, and bananas I think your best bet will be to keep them separate. The lemon juice will benefit both the apples and bananas, but might only be marginally effective if unnecessary for kiwi -- since kiwi brings plenty of its own citric acid to the table.

The fruit should be stored in the refrigerator to additionally inhibit oxidation. In my experience covering it with plastic wrap with a few holes poked in it works great. Aluminum foil should be fine as well. I find that the covering is primarily to protect your fruit from picking up other odors from within your fridge, and the holes permit the fruit to "breathe" releasing the buildup of ethylene gas that will occur if it is completely sealed.

If lemon juice is undesired you can use other citrus juices including: lime juice, orange juice, and pineapple juice. Obviously they will all bring their own flavors. If this flavoring is altogether undesired, then you should consider getting a commercial product called Fruit-Fresh. It's basically a powdered citric-acid, and kosher to boot.

Check more discussion of this question.