I had an overly-ripe persimmon today and holy crap that was the sweetest piece of fruit I’ve ever eaten. This got me thinking- what exactly happens when a fruit ripens? And does a very ripe piece of fruit contain more fructose?
Yes and no. Carbs are sugar, and the fruit doesn’t increase in carbohydrates as it ripens. Unripened fruit contains more complex carbs that are resistant to digestion (fiber). As the fruit ripens these complex carbs start to breakdown into simple sugars, making the taste sweeter. The sugar content isn’t changing, but the form and bioavailability of the sugar content is. This is why the riper the fruit is, the higher it’s glycemic index will be. Other than this though, ripe and unripened fruit will have very similar levels of nutrients overall.
Fruits go through 4 distinct stages of development, your concerned with the final ripening stage. During the 3rd stage while fruit is growing it is provided sugars synthesized in the leaves and any not used are stored in the cell walls as starches and acids. As the fruit ripens these starches and acids decrease and convert back to sugars making the fruit sweeter and YES increasing the sugar content. (Refer to On Food and Cooking by Harold McGee)
I hope this helps answer your question. Be happy, healthy and safe and remember to do what you love!
Not are carbs are bioavailable to us.
Some carbs are more than others (glycemic index).
Example: bananas when green have a toooonnnn of indigestible starch. If you eat them before ripening it’s likely to give you tummy problems. Ripening is where the starches are broken down into more bioavailable form (sugar) and generally when we eat them they’re a mix of largely indigestible starch and sugar.
This also means that even though their sugar content is somewhere around 20g, their actual glycemic index is lower
Yes it mostly goes up. Sugar is produced from starch or other longer carbohydrates mostly. Most fruits get their sugar transported to them in the plant. But a lot will also produce some during ripening.
https://www.frontiersin.org/articles/10.3389/fpls.2020.564917/full
In many fruits also tannins and acid profiles change. Making the fruit appear more sweet because astringent, butter or acidic components are removed
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. So it does get sweeter.