Why does fruit ripen? What causes the ripening process?

Nothing can compare to the taste of fruit when it is ripe. Ripeness incredibly unleashes its best texture, delicious flavor, and enticing smell. However, try to eat a few days earlier, and you will have a different or lesser experience. But, have you ever wondered why does fruit ripen and what causes it do so?

Well, fruit ripening is part of how plants propagate themselves naturally. The ripening of the fruits is a way for animals to consume the seeds inside the fruits. Once an animal eats the fruit, the seeds would be hard for them to digest and will release them in their poo. As they move around, they will be able to ‘transport’ the seed and help a new plant grow into a new place.

However, it takes time before the seeds are mature enough to grow into plants. Plants want to ensure that animals only eat their fruits at the ideal time. With that, most fruits stay green to serve as their ‘camouflage’ among the leaves, making them harder to spot. Moreover, they tend to have a bitter flavor, so that animals won’t prefer to consume them.

Now, as the fruit grows, the plants brim its storage cells with water, starches, sugar, vitamins, minerals, and organic. With that, the color of fruit starts to change into more visually-enticing colors, such as yellow, orange, and red.

As days continue to pass by, organic acids and starch content lessen, while upping the sugar composition. Thus, making the fruit sweet. Meanwhile, as the protein and acid components also change, the distinct sweet-smelling scent of the fruit starts to build up. Then, the texture of the fruits becomes softer as its cell walls begin to ‘collapse.’ All of the processes contribute to the ripening of the fruit, making them more edible to animals and humans.

But, what instigates these changes? Well, thanks to the incredible enzymes, the instigator of many chemical reactions, and changes in the world of microbiology, we are able to eat ripe fruits. Enzymes are responsible for tearing down the green pigment in plants, allowing fruits to change color. Moreover, enzymes are also behind how starches transform into sugars.

Another catalyst is the hormone called ethylene, which builds up within the fruit during the ripening process. While it isn’t clear how ethylene exactly functions, it is believed that this hormone allows the cells of the fruit to become penetrable. Through that, enzymes are able to do their ‘magic’ to the fruit.

Also, ethylene changes how the fruit cells breathe. Once the fruit accumulates a certain amount of ethylene, its cells would shift from releasing oxygen and will start to expel carbon dioxide instead. That is a process of cellular respiration, as fruits absorb oxygen to procure the energy its needs to ripen and releases carbon dioxide as a by-product.

Ethylene is also used for why fruits tend to become perfectly ripe when they reach supermarkets. Certain fruits, such as avocados, kiwis, pears, bananas, peaches, and apricots never ceases ripening and build up even after getting picked. They enter a period accompanied by an ethylene burst, which they have retained in the final stages of their maturity. However, they can also get ethylene from the environment.

With that, commercial companies pick the climacteric fruits when they are still underripe. The procedure is done to lessen the damage during shipping and ensure the longevity of the fruit. Once they are ready to be sold, they are gassed with ethylene as they are brought to stores and supermarkets, making them ideally ripe.

More Readings:

Ripening (Wikipedia)

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