Why Some Fruits Ripen Once Picked and Others Don't, According to Science

Comparing apples to oranges, there is one big difference between them when it comes to ripening.

By
Lauren David
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Lauren David
Lauren David is a Chilean-American freelance writer, who loves writing about food, gardening, and nutrition. She's been published in many digital publications, including Allrecipes, Better Homes & Gardens, Huffpost Food, MindBodyGreen, The Kitchn, Southern Living, and more.
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Updated on 07/6/23
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Ever wonder why that mango you buy continues to ripen at home, while the strawberries don’t get any sweeter or juicer, and instead just start growing mold? Turns out, it’s not random. “Ripening is a very complex and highly coordinated metabolic process,” explains Rob Blakey, PhD Agric, Research & Development Director at Stemilt. And according to Farm Manager Dominique Kline at The Hope Farm in Alabama, “Some fruits have a mechanism that synthesizes ethylene, a naturally occurring hormone that plays a role in the composition change and starch conversions into sugar that happens during the ripening process.” 

When it comes to fruit ripening, there are two categories of fruits to keep in mind to help break the mystery of the “will-it-keep-ripening?” saga: climacteric and non-climacteric fruit. “Climacteric fruit can [continue to] ripen off the tree when they are mature; non-climacteric fruit have to mature and ripen on the bush or tree,” explains Dr. Blakey. 

Climacteric Fruits

Fruits that ripen after harvest are often picked before they’re ready so they can be transported long distances before they reach the produce aisle. “Climacteric fruits tend to be delicate in their fully ripened state and can be more susceptible to damage during transport, and in commercial production, are often force-ripened by exposure to ethylene near the area of sale or consumption,” explains Kline.

Common Climacteric Fruits

“A few common climacteric fruits that will continue to ripen after harvest include bananas, avocados, tomatoes, peaches, mangoes, kiwis, apricots, plums, and papaya,” explains Kline. 

Dr. Blakey adds that apples, pears, and melons will also ripen after being harvested. “Many tropical fruits fall into this category, permitting them to be transported into colder climates for distribution,” says Kline.

Non-Climacteric Fruits

“Non-climacteric fruits must ripen while still attached to the plant and generally will not respond to external ethylene,” says Kline. “They may get softer after harvest, but this is due to more of the fruit degrading rather than ripening.”

Common Non-Climacteric Fruits

These fruits will not continue to ripen after harvest, so make sure you buy only those at their peak.  “Cherries, strawberries, watermelon, pomegranate, oranges, grapes, pineapples, and blueberries,” says Kline. He recommends always buying these fruits ripe.  “Citrus fruits are non-climacteric, but since they’re larger you can keep them longer at home without them losing eating quality,” says Dr. Blakey. However, an under-ripe lime or lemon is just going to be nearly dry, and an under-ripe orange will often be very bitter. 

How All This Should Impact Your Grocery Shopping  

There are several tips and tricks to figure out which fruits will continue to ripen at home.  “The easiest way to know if a fruit is climacteric is if there are big changes in color, flavor, aroma, and/or texture,” says Dr. Blakey.“ For example, hard and green fruit will change to soft and yellow.”

You can purchase different levels of ripeness so you can choose according to what you need for the week. “Climacteric fruit continues to ripen so they are usually good for a few days to weeks, depending on what ripeness stage you like to eat the fruit,” says Dr. Blakey. 

Take avocados, for example. If you’ve ever purchased a variety of these delicious fruits that were both ripe and hard, then you know you want a slightly soft one to eat within a day and harder ones that will be ready to eat in several days or a week.  

Non-climacteric fruit should be purchased at their peak.  It will give off clues when they’re starting to go bad or lose their  appeal. This is known as senesce. “Senesce refers to when fruit gets old and breaks down and starts going mealy or browning,” says Dr. Blakey. “Non-climacteric fruit lose water, shrivel and senesce so they should be eaten soon after purchase for the best eating experience.”