Do you ever wonder why bananas will ripen when placed on the counter, but strawberries will not? The reason for this is that there are two different types of fruit: fruit that will continue to ripen after they are harvested (climacteric) and fruit that will not continue to ripen after they are harvested (non-climacteric). By knowing which is which, you can use that as a guide to help you when selecting produce at the grocery store and with your at-home ripening process.
Ripening Process of Climacteric Fruit
There are a few main factors that come in to play with the ripening process of the climacteric fruit:
- Whether or not a climacteric fruit can ripen to its full extent is dependent on if the fruit was harvested at the proper maturity stage. An example we can all relate to is with tomatoes. Tomatoes are climacteric fruit that continue ripening after harvest. However, they need to reach a certain maturity stage while still on the plant in order to ripen properly after harvest. If not and they are harvested prematurely, it results in the issues we see with store-bought tomatoes that cannot compare to home grown tomatoes. You can read more on that topic here.
- As climacteric fruit ripens, it naturally produces ethylene gas. When the fruit is exposed to more ethylene gas, it acts as a natural catalyst to further the ripening process. For example, have you ever heard of the “trick” of putting a banana and an apple in a paper bag together to ripen the banana? People do this because the apple is already in the ripening process, and is giving off ethylene gas. This ethylene gas acts as a catalyst for the ripening process of the banana. This same concept can be applied to other climacteric fruit stored together in a bag or on the counter. For example, if you put ripe bananas in a bag with a hard avocado, the ethylene gas given off by the bananas will help speed up the avocado ripening process.
- If climacteric fruit is kept at a lower temperature, ethylene will not have as much of an impact. This is why avocados from the store will only ripen when placed on the counter versus the fridge.
What Happens to Non-Climacteric Fruit?
After harvest, non-climacteric fruit does not continue ripening. However, it does continue breathing and respiring. This ultimately leads to fruit aging, but does not result in any further ripening of the fruit.
Climacteric Versus Non-Climacteric
You can use the table below as a guide to help you select fruit at the grocery store (Kader 2002). There is a common misconception that pineapples will continue ripening on the counter, but that is not true. The same goes with strawberries that are not fully colored, as they will not change in color or continue ripening after harvest. However, if you buy a pear and set it on the counter for a few days, it will soften and become sweeter.
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Kader, Adel A. “Postharvest Biology and Technology: An Overview.” Postharvest Technology of Horticultural Crops, 3rd Edition. Oakland, CA: University of California Agriculture and Natural Resources, 2002. 39-47. Print.