The salt water trick keeps apples from browning

A ten-minute salt water soak stops cut apples from browning, and lime juice does the same for avocado — both survive until lunch.

Browning is just oxidation. The enzyme in the fruit reacts with air and turns brown. Kill the enzyme or block the air and the fruit stays pale. The easiest fix is an acid bath.

For apples: dissolve about half a teaspoon of salt in a cup of water, drop in your slices, wait ten minutes, drain, and pat dry. They won’t taste salty at that concentration and they stay white for hours. Lemon juice works too but your apples taste like lemon. Citric acid powder is the upgrade — a pinch in water does the same job with zero flavor change.

For avocado, brush the cut surface with lime juice and leave the pit in the half you’re packing. If you’re doing slices, a quick toss in lime juice is enough. One trick some people swear by: toss a chunk of red onion in the container. The sulfur compounds slow browning. It works, but your whole lunchbox smells like onions, so weigh that one.

Brown fruit isn’t dangerous, it’s just ugly. But kids (and adults) eat what looks good.