Why apples and bananas cause other fruit to spoil
Everyone knows that when they buy bananas at the supermarket, the bananas are green and hard. Once home, they will quickly ripen and become softer, sweeter and more palatable. The truth is that those bananas did not magically arrive at the store just one day before they were ready to turn golden yellow and delicious. They were purposely kept from ripening until they reached the store by the growers who transport them in airtight, refrigerated conditions. Once they reach the store, they are gassed.
It's a Gas
I heard you gasp when you read the word “gassed”. But you needn’t worry. The gas that is used to ripen fruit is the same one that the fruit itself produces - ethylene gas. Ethylene gas triggers many processes in fruits, one of which is to cause it to ripen. Production is slowed by the refrigeration and lack of air, but when you expose your bananas to the warmth of your kitchen, they will begin to quickly ripen. In the same way, you can keep ripe bananas from getting too soft, mushy and brown by putting them in your refrigerator. The cold slows the production of ethylene gas. The banana’s skin will turn black, but the fruit inside will stay firm and delicious.
Apples are also a prodigious producer of ethylene gas. Because ripening apples will produce a lot of ethylene gas, it is best to store them away from other fruit unless you actually want the fruit to ripen more quickly. Like bananas, apples will stay firm and tasty in the refrigerator for a long time but will quickly over-ripen if left out in the open. On the other hand, if you want your apples or any other fruit - pears, peaches, plums - to ripen more quickly, put the fruit in a paper bag and fold down the top. The bag will concentrate the ethylene produced by the fruit and the higher concentration of gas will cause the fruit to ripen rapidly.
How to ripen tomatoes
The paper bag trick is also useful for ripening tomatoes. Picking tomatoes just before ripeness may save them from bursting on the vine or being ravaged by insects and other pests. To ripen those tomatoes quickly in the house, place them in a paper bag with a ripe apple, fold down the top of the bag and let the ethylene gas do its work.
Watch for spots
Conversely, to keep fruit from ripening too quickly or going mushy, make sure you remove any piece of fruit that has dark spots or is going mushy. A banana with dark spots is producing more ethylene than one that has just started to turn yellow. It is usually best to keep both apples and bananas stored separately from other fruits, to avoid ripening of the other fruit and shortening its shelf life.
Stay in control
The ability to keep fruits from ripening too quickly allows produce to be shipped fresh to your supermarket at any time of year. In the same way, understanding how ethylene gas works to ripen fruit and how to control ripening will help you keep fruit fresher, longer. Use these tips to avoid spoilage and enjoy serving fresh, delicious fruit to your family in any season.