Science Questions

Do unripe pairs contain the same about energy as ripe pears?

Tue, 22nd Mar 2016

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Denis Ripley asked:

Is the energy available to us from pears the same for unripened fruit (with more starches) as for ripened fruit (where starches are converted into sugars) ?


We put Denis' question to nutritionist Toni Steer...Juicy Pear

Toni -   I think the short answer to Dennisí question is no.  The human body is very efficient at extracting calories from food.  There is some evidence to show, and Iíve looked at this actually with ripe and unripe bananas, is that with the riper banana you get a slightly quicker rise in blood glucose.

Chris - Did you eat an unripe banana?

Toni - This isnít me.  This is a paper soÖ

Chris - Oh, so you make some other poor person eat it.  Thatís disgusting!

Toni - It wasnít that bad.  So with the unripe banana you see a slightly slower rise in blood glucose, so you could probably apply that same kind of theory as well to the pear in question but, nevertheless, the digestion of the starches and the sugars is very efficient.  So we have the amylase in the mouth that breaks down the starch.  Youíve got the stomach that mixes the food and breaks it down and actually, by the time you get to the small intestine, around about 50% of your starch is already started to be broken down.  Then the breakdown really into the monosaccharides or the simple sugars from the fruit occurs then in the small intestine so, by the time time it gets to the small intestine itís very efficiently broken down and very efficiently absorbed.  So I think the answer is; donít worry about the ripeness too much - youíll get the calories from it.


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The label on my bag of Pears says that (amongst other things) they consist of '10% Carbohydrates of which 10% are Sugars'.
So I'm guessing that the label suggests that all the starch is converted to sugar (either as it becomes fully ripe or as it's assimilated in the gut) ?  The label says it's got 204kj or 48 kcal.
I believe sugars are more easily assimilated than starches...but maybe that just means it's assimilated quicker rather than more efficiently ? c0sm0, Wed, 10th Jun 2015

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