Why do bananas ripen

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By Katie Jackson. Food How to make Magnolia Bakery's famous banana pudding. Courtesy of Gaby Dalkin. Get The Recipe. Banana Blueberry Smoothies Gaby Dalkin. Jocelyn Delk Adams. Banana Pudding. Katie Jackson. Facebook Twitter Instagram Instagram Adventure. Popular this week A long way from home: Antarctic penguin makes it all the way to New Zealand New Zealand conservationists have released an adelie penguin back into the sea after the Antarctic-based bird swam thousands of kilometres to make a rare visit.

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The three main polysaccharide of the cell wall are cellulose , hemicellulose and pectin. Cellulose is made up of hundreds of glucose sugars joined together to form a long chaiin; hemicelluloses are also long chains of sugars, but unlike cellulose, these can include many different types of sugar, such as glucose, xylose, galactose, and mannose and instead of being linear are branched structures; pectins are also long branched chains of sugars, but in this case the sugars are galacturonic acid, rhamnose, galactose, and arabinose.

As the cell wall begins to break down, the fruit starts to get softer [ 2 ]. Cell wall breakdown happens when proteins called enzymes dissolve these important cell wall polysaccharides. The activity of these enzymes is directly linked to the shelf life and texture of the fruit [ 2 ].

Fruit softness is also affected by the fluid pressure inside the plasma membrane called turgor pressure. Turgor pressure keeps the fruit firm, just like air pressure inside a balloon keeps the balloon firm. After maturation or harvest, fruits lose fluid water , causing a decrease in turgor pressure, so the fruits shrivel. During ripening, there is an increase in the breakdown of starch inside the fruit, and a corresponding increase in the amount of simple sugars which taste sweet, such as sucrose, glucose, and fructose.

This process is particularly obvious in bananas as they ripen. Green bananas do not taste sweet at all, and the riper they get, the sweeter they taste. There is also a decrease in acidity as the fruit ripens and a decrease in bitter plant substances, such as alkaloids. Last, as fruits ripen they produce complex compounds that are released into the surrounding air, giving a ripe fruit its pleasant aroma.

Through these changes, fruits ripen and become sweet, colored, soft, and good-tasting. A major concern with ripened fruit is that it does not last very long before it begins to spoil. The loss of firmness and the production of sugars associated with ripening can also make the fruit susceptible to pathogens like bacteria and spoilage. Over-softening of fruit is a major cause of spoilage during transportation, particularly for tropical fruits, such as mangoes and bananas.

Spoilage can be reduced by rapid transportation of fresh fruits, or by slowing down fruit ripening. There are several ways to slow down fruit ripening. One way to slow down ripening is by lowering the temperature. Cold temperatures above freezing are usually used. The peel also becomes softer as it ripens, making bananas bruise much more easily.

Bruising causes yet another enzyme called polyphenol oxidase to speed up oxidation, turning a banana peel brown, and eventually, almost black. The flesh may also turn brown if the bruising is deep enough.

You can speed ripening by loosely covering unripe bananas to concentrate the ethylene gas emitted by the fruit. Bananas have the best flavor and texture when the peel color deepens to a golden yellow with just a few brown spots. This article was written by a professional writer, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.