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Science Why it's so hard to treat pain in infants. Science The controversial sale of 'Big John,' the world's largest Triceratops. Science Coronavirus Coverage How antivirals may change the course of the pandemic. Travel A road trip in Burgundy reveals far more than fine wine. At this stage, fruits are generally hard and unattractive to predators—including us! After seed development and fruit growth, the properties of the fruit change to make the fruit more attractive to potential consumers, such as animals, birds, and humans [ 1 ].
These changes include the most common ways by which we judge whether a fruit is ripe or not, including external features, such as softness to the touch, and internal features, such as sweetness. Fruits also change color as they ripen. This happens because of the breakdown of a green pigment called chlorophyll, along with the creation and accumulation of other pigments responsible for red, purple, or blue hues anthocyanin , or bright red, yellow, and orange hues carotenoids , to name a few.
First, how is fruit softness regulated? The softness or firmness of a fruit is determined by the state of its cell walls. 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. Even though all fruit can be frozen, upon thawing many fruits lose their flavor and their texture and become very mushy.
Raspberries are a possible exception—they can often be found frozen in the grocery store. Normally, to freeze fruit, the fruit is first cut into small pieces and when thawed, these pieces can be used to make purees or smoothies.
India, China, the Philippines and Ecuador lead world production. Bananas are grown in tropical areas and can produce nearly year-round, so seasonality is not particularly relevant to the fruit, except in those states where they are grown. Ripen green bananas on the counter. You can also store them on the counter — but note that they will continue to ripen, and sometimes pretty quickly, depending on how warm it is.
Contrary to popular belief, you can store bananas in the refrigerator, but only after they have become the exact level of ripeness you want. Keep bananas away from highly perishable fruits and vegetables; bananas give off high levels of ethylene gas that promotes ripening and eventual decay in many fruits and veggies. The most common way to eat bananas is of course, out of hand. Bananas are frequently paired with their tropical brethren: think coconut, rum, chocolate and citrus. They are also commonly paired with warming spices like cinnamon and nutmeg and dairy products like ice cream.
Because bananas tend to get soft and much sweeter the riper they get, the ripeness of your banana should dictate what you do with it. There are a couple of famous banana-based desserts, each with their own interesting history. Bananas Foster , a dish of caramelized bananas with banana liquor and rum, was invented in New Orleans in The banana split was invented in Latrobe, Pennsylvania in Banana cream pie first began to appear in print in the early s.
You can also find or make banana vinegar and banana wine popular in parts of Africa. Bananas freeze beautifully — just peel them and stick them in a zip-top bag for use in smoothies and other yummy recipes, like this amazing banana ice cream , no ice cream maker necessary. You can also make your own banana chips in the oven.
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