Loss of Nutrients in Fruit after chopping?

[Datel]

I think I read somewhere that fruit, maybe veggies too, that is cut open or pureed loses a lot of nutrients after a very short time, maybe after half an hour, I think it should have been 50%. But other information seems to suggest that it is not true at all.

This would also mean that you lose a lot of nutrients when you dry them.

So what is correct? Or where can you find information about it?

 

[Lou]

Good question.
But no simple answer.

Just need to back up a little.
All. fruits and vegetable start losing some nutrients as soon as they are harvested. So you want to buy fruit that is as fresh as possible. Also they will lose nutrients slower if refrigerated. especially if they are in an air tight container. not being cut up probably helps but probably not so much as being fresh, refrigerated and in an an air tight container.

I've gone back and forth on this myself.
Years ago I was told that you wanted to take your veggies home and wash, dry, and prepare them right away and then store them in an air tight container.
The idea was that you are more likely to eat celery and carrots as a snack if all you have to do is take one out of the frig.
I don't do that anymore - but mostly cause I'm lazy.
However it's still not a bad idea - even if they lose some nutrients - if it gets you to eat more veggies you will make it up with quantity.

OH, and don't forget, some veggies increase in nutrient bioavailabity when cut, ie. celery.

Reading list.

Why Some Antioxidant Vitamins Degrade After Cutting or Slicing Produce

Cutting and slicing a vegetable or fruit leaves the flesh exposed to oxygen, with a reduction of some of the antioxidant vitamins, such as vitamin C.

www.verywellfit.com

EATING WELL; Store-Cut Vegetables Give Busy Cooks a Head Start (Published 2001)

Store-cut vegetables are a boon to busy home cooks; photo (M)

www.nytimes.com

https://www.npr.org/sections/thesalt/2018/01/25/580056584/can-chopping-your-vegetables-boost-their-nutrients

 

[Emma JC]

Google is usually my resource for getting answers however I do know that some vegetables have more nutrients available the further in advance that you cut them. In the case of onion, garlic and mushrooms, it is about 15 minutes or so, I don't know if there is an upper limit for them however I do occasionally cut my onions for Sunday morning beans, the night before.

Emma JC
Find your vegan soulmate or just a friend. www.spiritualmatchmaking.com

 

[Brian W]

I can't remember what it is exactly but broccoli produces something beneficial if you cut it 45 minute before cooking. Dr Greger spoke about it somewhere.

 

[Datel]

But no simple answer.

Well, I am used to that. Would be too easy.

not being cut up probably helps but probably not so much as being fresh, refrigerated and in an an air tight container.

So an air tight container helps preventing losing nutrients even if the fruits, veggies are in a refrigerator anyway.

However it's still not a bad idea - even if they lose some nutrients

Yes, washing them far before (not immediately before consumption) ought to lose them more (additionally to the amount of nutrients they would lose anyway) nutrients I once have heard.

OH, and don't forget, some veggies increase in nutrient bioavailabity when cut, ie. celery.

Oops, I didn't know that. Very strange, slicing celery increases the nutrients, so it works the other way. I know you have to grind / shred whole grain linseed to make the nutrients accessible for the body at all, but...and may be the smaller the peaces of the celery the more the nutrients increase...

But especially when drying, it would be extremely unfavorable if fruit and vegetables lost a lot of nutrients. Although drying should be a very good method to preserve food without losing (many) nutrients.

Many thanks for the links as well.

In the case of onion, garlic and mushrooms, it is about 15 minutes or so, I don't know if there is an upper limit for

Sorry, what is about, what for 15 minutes?

 

[Brian W]

I can't remember what it is exactly but broccoli produces something beneficial if you cut it 45 minute before cooking. Dr Greger spoke about it somewhere.

Sorry, 40 minutes and it doesn't produce anything but prevents loss during cooking.

 

[silva]

I can't remember what it is exactly but broccoli produces something beneficial if you cut it 45 minute before cooking. Dr Greger spoke about it somewhere.

Cutting or chewing raw broccoli does release sulforaphane but there is another way for cooking:

Flashback Friday: Second Strategy to Cooking Broccoli

I really like powdered mustard and have a shaker of nutritional yeast I mix with mustard and some garlic powder I add to most veggies.
I'd never remember otherwise

 

[Lou]

So an air tight container helps preventing losing nutrients even if the fruits, veggies are in a refrigerator anyway.

So the whole thing is having to do with Respiration.
For the most part, veggies are losing nutrients just by being alive and "breathing".
Cut off their oxygen supply and their respiration slows down. So they lose nutrients slower. Same thing with the frig - cool them down and they respire slower. and you stop all respiration if you freeze them or can them.

There is also the decomposition (rotting) thing. less oxygen and cooler temps mean that the bacteria that causes decomposition also slows down.

These are good general rules. but there are plenty of exceptions, i.e, bananas.

Aslo I buy that "living lettuce" which live in a ventilated container -with their roots attached.
and celery does pretty good standing up in a little bit of water with their leaves attached.

Yes, washing them far before (not immediately before consumption) ought to lose them more (additionally to the amount of nutrients they would lose anyway) nutrients I once have heard.

Don't think that really makes a difference. I like to wash my veggies as soon as I get home and before I put them in the frig. but that's mostly a connivence thing.

I'm also pretty sure that washing, drying and putting my strawberries in a ventilated container makes them last long. But I think that has more to do with fungus and rot than anything else.

Oops, I didn't know that. Very strange, slicing celery increases the nutrients, so it works the other way. I know you have to grind / shred whole grain linseed to make the nutrients accessible for the body at all,

And flax seed.

but...and may be the smaller the peaces of the celery the more the nutrients increase...

I don't think that is it. I think it's something to do with the celery thinking its under attack.

 

[Datel]

And flax seed.

It is not the same as linseed?

I don't think that is it. I think it's something to do with the celery thinking its under attack.

Simply halving was enough then.

 

[Brian W]

It is not the same as linseed?

Yes, I believe it is. I think in the US though with oil they differentiate culinary grade from general purpose like they do with canola and rapeseed.

 

[Datel]

Okey, so then one might have a better quality than the other.

 

[silva]

Flaxseed is US & linseed in UK
Canola US (and Canada?) Rapeseed UK

Just to add, sometimes obsessing over how to prepare foods for optimum nutrition can just lead to spoilage. I've done that, made a point to buy organic veggies, bring them home and not have time to wash and prep, thought about just letting it simmer, but no need to make them such and such....next thing I knew I was deciding if they were even edible anymore

Best way to eat vegetables? The way you'll really eat them!
I mean of course you should know best, but if you find you're not getting your servings everyday do your best. I mostly rely on frozen

 

[Lou]

I agree ^

Freezing does destroy some nutrients. but most veggies are frozen the same day they are harvested. so fresh veggies may have lost even more just because they were harvested last week.

Canned seems to be the cheapest. maybe not the tastiest. but I like to have a couple of cans of peas and corn in the house all the time. Add it to my salads or add it to my soups - and almost no prep time.

But yeah the most important thing is that you eat them before they go bad.

 

[Datel]

I think fruit (e.g. apples, pears), vegetables that are offered out of season are stored frozen in warehouses anyway, right? This is also frozen food, but it is not recognizable as such in the store.

 

[Lou]

I think fruit (e.g. apples, pears), vegetables that are offered out of season are stored frozen in warehouses anyway, right? This is also frozen food, but it is not recognizable as such in the store.

no.

th

ere might be some exceptions. I know oranges are stored in some strange gas (but not frozen).
Maybe potatoes, too. (but not frozen). Fun fact: potatoes are frozen before they are shot out of gun and turned into French fries.

For most fruit and veggies that you buy out of season - they are just being shipped (sometimes by plane) to the market. Lots of stuff in the us comes from South America.

US Pears are an exception. their seasons over lap so there are almost always fresh ones available.

Apples are kept refrigerated before they get shipped to the grocery store. They even have special low temp and low oxygen warehouses for apples. The apples in stores right now are like 10 months old. BTW, at home apples stay a long time in your refrigerator.

 

[majorbloodnok]

Ultimately you're dealing with three variables:

• Which nutrients are present and, therefore, how they behave
• How easily those nutrients can be accessed by the person eating the fruit or veg
• How much of each of the nutrients in question there is in the fruit or veg

Regarding the first point, a nutrient like lactose or protein is very stable and won't degrade of itself over time, but the fruit will still continue respirating and so may use some of it up itself. In contrast, vitamin C is markedly less stable (particularly when you consider it is water-soluble and many people wash or soak fruit), so the fresher the fruit or veg the better.

Regarding the second point, it doesn't much matter how concentrated a nutrient is in a plant if your body can't get to it. There's loads of iron in spinach but it's not in a readily absorbable form. If you whizz up and blend your fruit to a smoothie it makes it much more easy for your body to get to those nutrients - including all that sugar that's now freely available to rot your teeth and give your blood a sugar spike. Readily available is not always good. However, particularly with fibrous vegetables like celery, chopping fairly small is a great idea to help expose those nutrients.

Regarding the third point, modern intensive farming - especially producing out of season veg - has definitely reduced the nutritional value of a lot of shop-bought fruit and vegetables. Packing in the nutrients takes time so if farmers and scientists try to grow the produce we want in half the time it's pretty understandable where the hit is going to be.

One point not touched on, however, is the amount of any nutrient we actually need. Just one orange contains about 80% of the recommended daily allowance of vitamin C even before you consume any of your other veg, so leaving an orange around in the fruit bowl for a few days is not going to cause you to have a vitamin C deficiency. However, some other trace elements or vitamins may well require you to eat certain veg as fresh as possible.

In practice, if you cook your veg lightly (steaming preferred to boiling to death) and eat it whilst it still looks nice and fresh then you'll be getting a perfectly reasonable amount of nutritional value that is more than enough to keep you healthy. If you want the best nutrition possible, grow your own even if it's just a few herbs in a window box.

 

[Datel]

For most fruit and veggies that you buy out of season - they are just being shipped (sometimes by plane) to the market.

So they are more or less fresh like the domestic ones.

vitamin C is markedly less stable (particularly when you consider it is water-soluble and many people wash or soak fruit), so the fresher the fruit or veg the better.

Does washing fruits lose vitamin C (or others)?

including all that sugar that's now freely available to rot your teeth and give your blood a sugar spike.

So the sugar behaves differently than in the intact fruit?

 

[silva]

@Datel -- I highly recommend this book, it looks to be written only in English--

Amazon.com

Whole by Colin Campbell (thought the link would show the name!)

It is fascinating how much there is to digesting and utilizing foods. The start of breaking foods down to be digested starts right in your mouth, breaking down by chewing and the start of digestion with your saliva.

 

[Lou]

So they are more or less fresh like the domestic ones.

Yes, but a much bigger carbon footprint.

Does washing fruits lose vitamin C (or others)?

I doubt it - the nutrients should be safe inside the fruit.

So the sugar behaves differently than in the intact fruit?

I don't think blending fruit makes a big difference. Juicing would cause it removes the fiber. but the conventional wisdom is to juice vegetable and blend fruit

 

[silva]

I don't think blending fruit makes a big difference. Juicing would cause it removes the fiber. but the conventional wisdom is to juice vegetable and blend fruit

You should drink smoothies slowly so your saliva can start the digestive process

Green Smoothies: What Does the Science Say? | NutritionFacts.org

Might disrupting the fiber by blending fruit result in overly rapid sugar absorption?

nutritionfacts.org