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How Dehydration, Ripening and Storage Affect the FODMAP Content in Fruit

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FODMAP & Food Processing Series

Article 1

In this installment of my FODMAP and Food Processing series, I’ll focus on how and why dehydration, ripening and storage conditions affect the FODMAP content in fruit.

Want to learn more? Read our next articles in this series:

Close up of fruit dehydrating on racks
Dehydration, ripening and storage conditions affect the FODMAP content in fruit.

Monash University & FODMAP Friendly

Anyone familiar with the Monash University Low FODMAP Diet Smartphone App or the FODMAP Friendly app has doubtless found themselves wondering why some fruits get a Green Light when they’re in one form, and a Red Light when they’re in another. The reason for this is that the FODMAP content in plant foods is affected by storage time and temperature, water content, and ripeness among other things.

Because of this, fruits such as grapes and their dehydrated counterpart — raisins — have to be individually analyzed for FODMAP content; it’s not enough to test one and assume the same results for the other. Accordingly, the items I will be discussing have been subjected to laboratory analysis — just like all foods found in the both of the aforementioned apps.

These are the two apps that we recommend as these are the two entities that are conducting the lab testing and considered primary resources.

A Grape’s Defense Mechanism

Grapes and raisins were my gateway into the world of weird FODMAP science, but the main reasons grapes get a Green Light rating and raisins a Red are quite straightforward: a) we tend to eat more raisins than grapes because they’re so much smaller b) removing the liquid from high water content items such as fruit shrinks the overall volume of the food and concentrates all its other components.

In the case of grapes, one of the “other components” is oligos-fructans, i.e., the “O” in FODMAP.

The weird science part of why raisins are higher in FODMAPs than grapes has to do with the fact that the dehydration process actually increases their overall fructan content. Apparently, the same goes for fresh pineapple and papaya (paw paw in the Monash App) and the dried versions of these fruits.

The closest I could get to an explanation for why this might occur was a 2003 study showing that fructans help preserve a plants membrane barrier during dehydration.

Presumably, as the water content in grapes (and pineapple and papaya) decreases, the fruit generates fructans as a way to defend itself. Too bad humans can’t do the same thing − our skin only gets more fragile the drier it gets!

Grapes and Raisins on the low FODMAP Diet- Food Processing Series

Bananas Also Defend Themselves

Bananas are another head-scratcher in the fruit category. I’ve been helping people navigate the low FODMAP diet long enough to have seen the common banana go from low FODMAP to high, and then somewhere in between.

This popular fruit is a great example of how environmental factors can influence a food’s FODMAP content.

Similar to grapes, bananas accumulate fructans as protection when their environment stresses them out. Cold weather is just such a stressor. While a cold climate is not typical of the tropics, where bananas come from, it is typical of the environment in which bananas are stored and ripened.

The longer a banana spends ripening in cold storage, the higher its fructan content. This means that if you’re sensitive to fructans, you may need to limit yourself to a measly ⅓ of a medium ripe common banana, i.e., the amount listed as low in FODMAPs in the Monash Smartphone App. Better yet, why not incorporate bananas into recipes like we did in these:

Bananas and the Low FODMAP Diet - Food Processing Series

For more information, read our article, Are Bananas Low FODMAP? which delves even deeper into this beloved fruit.


Before you assume all unripe fruit is lower in FODMAPs, consider the guava. According to the Monash App, ripe guava contains little to no FODMAPs, while the unripe fruit is a fructose nightmare.

Why? I don’t know, but I’ll keep you posted as more information becomes available!

Guava - Food Processing Series - Low FODMAP Diet

FODMAPs Can Change

And then we have changes in FODMAP content as seen in fruit like mango. Ripe, fresh mango has been shown to contain fructose in Monash University lab testing. Dried mango shows fructan content.

This is a great example of how we cannot make assumptions about how ripening and/or dehydration might affect FODMAP content of foods.

Let’s Look At Avocados

FODMAP Friendly overhauled their smartphone app in early 2022, not only from a design perspective but they also added many more tested and re-tested foods. They took both ripe and unripe avocados into the lab, and guess what? The FODMAP content did not change. Monash University has only lab tested ripe avocados, so this is new information for all of us.

You may want to read: Is Avocado Low FODMAP?

The Takeaway

When in doubt, check the Monash University and FODMAP Friendly smartphone apps for the most comprehensive and current information about your favorite foods. Both entities are constantly testing and re-testing foods and the apps are the best way to keep up-to-date.

In brief, the FODMAP content of grapes increases upon drying and becoming raisins; bananas show higher FODMAP content upon ripening; guavas show lower FODMAP content upon ripening; and in FODMAP Friendly lab testing, avocados showed no difference in FODMAP content between ripe and unripe.

If there’s anything I’ve learned in my years of working with this diet, it’s that things don’t always seem to make sense in the FODMAP universe!

So, what does this mean to you? We understand that this information can seem confusing. We suggest that you look at it this way: lab testing is accurate, but you are not a lab. Lab testing is representing the samples that were tested at a particular time, and the fruits and vegetables you eat will be different. They will be from different countries and climates, harvested at different times, storage procedures will vary. They might not even be the same varieties. Look at lab tests as lines in the sand from which to begin your exploration of FODMAPs. How you tolerate a particular food is what is important.

For more information on how tests are conducted, please read our articles Monash University Lab Testing Explained and also FODMAP Friendly Lab Testing Explained.

Here at FODMAP Everyday® we strive to bring you information that we hope makes navigating this diet a little bit easier and a whole lot more delicious!

Want to learn more? Read our next articles in this series:


Ingrid J. Vereyken, Vladimir Chupin, Folkert A. Hoekstra, Sjef C. M. Smeekens, and Ben de Kruijff. The Effect of Fructan on Membrane Lipid Organization and Dynamics in the Dry State ( Biophys J. 2003 Jun; 84(6): 3759–3766.

Update: Bananas Re-Tested! ( May 16, 2017. Citation from

UPDATE! Newly tested foods: the mysterious case of the guava ( March 22, 2016. Citation from


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