What difference does the ripening of fruits make in their glucose levels?

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I’ve heard a lot of times that certain fruits like bananas and mangoes have more sugar levels in them because they are sweet tasting. I saw a lot of people eat non ripe ones saying it’s fine though. What’s the difference?

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4 Answers

Anonymous 0 Comments

To understand the answer to this question you have to understand how polymers work. Polymers are a long repeating chain of the same molecule repeated over and over again. Plastics are the most familiar polymer to the general public, but many polymers exist in nature as well. Your DNA is another polymer, as it is comprised of the same units repeated over and over: T, A, C, and G. This units are called monomers, and when a bunch of monomers bond together they form a polymer.

Okay, so you asked about sugars and not plastics. Well, like I said many polymers exist in nature, many of which use glucose as their monomer! Starch and cellulose both use glucose as their monomer, and the only difference is in how those two sugar molecules are linked up (this bond is called a glycosidic bond, and well come back to it). Humans produce an enzyme that can break apart the bond between the starch molecules, which is why starchy foods tend to also taste sweet (bread, potatoes, etc). However, we don’t have an enzyme that can break apart the bonds in cellulose, yet other animals do.

So, the answer to your question is, as the fruit ripens, some of the glycosidic bonds break down, raising the available sugar content in the fruit and making it more sweet!

Edit: to clarify, it is the starch and the pectin that is most responsible for the increase in simple sugars via glycosidic breakdown, not cellulose. I only mentioned cellulose to illustrate how important the type of linkage between these identical monomers can play; I find is fascinating how often molecules that are otherwise identical can have vastly different roles in biologic systems.

Anonymous 0 Comments

As a diabetic, i’ve been told to avoid fruits that are too ripe, because they have way much sugar.

So i suppose, the rippening is transforming some components into sugar.

Anonymous 0 Comments

Starch is a bound chain of sugars. think links in a chain
this is time stable calories
as it ripens some sugar is clipped off the starch molecules
when eaten the calories in the sugar is available sooner
So when you eat a ripe sweet fruit, the sugars will be rapidly be absorbed in your gut and into your blood
your blood sugar level will go up

If the food is not sugary, say under ripe or starchy, the extra step of un-linking the starch into sugars will have to happen

but it will happen
and the starch will be made into sugar into sugar and then absorbed from your gut into you blood

If a small amount so starch is eaten likely not a spike in blood sugar
The equivalent amount of sugar will be absorbed mush faster
and if enough give a notable jump in blood sugar levels

However a huge meal of starch as it is digested will raise your blood sugar level

Anonymous 0 Comments

I know bananas start out as mostly starch and the starches break down into simpler sugars as they ripen. Cooking or blending bananas can do the same thing. I’m not sure how universally that applies to other fruits but green bananas definitely have less sugar than ripe ones