Blanching vegetables destroys nutrients?

In the Cheff Steps video "Pretreatments for Sous Vide" (https://www.youtube.com/watch?v=Re0HtXK8oQ8) mentions blanching plant-foods (vegetables) to kill bacteria and enzymes in the plants tissues and I would like to know if this is compatible with a Green Smoothie diet where only raw greens are used.

Typically I would wash either Kale or Spinach under cold water, separate it into portions and then freeze it, retrieving it when required each day.

Should I be blanching instead?

I read that high temperature would destroy the nutrients in vegetables.

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tshewman

A brief blanch is a good idea for a couple of reasons. The Oxalic acid in both spinach and kale is part of the plant's protective system, but is somewhat toxic to us (don't worry, you'd have to eat about 15 cups of it at once) and it also binds to other vitamins and such, so the brief blanch or steam solves that problem by handling the OA and making those nutrients available.

Samuel__253807

I usually rotate between Kale and Spinach every other day, to remove the build up of what my body interprets as a toxin. But for me the main issue was hygiene.

I have looked into using alkaline water to wash vegetables, or vinegar and all such things, to remove pesticides (I don't always buy organic, nor grow my own) and am concerned about getting the chemicals (oils) off the leaf as I know that oils and water don't mix, so using "hydrogenated water" was one solution?

I also read up on how nutrients degrade and it's fairly negligible when submerged in water, although steaming would reduce any leaching of nutrients into the water. On from this I read about steaming on on the hob, but in the microwave, which can even enable better absorption of nutrients from plant-foods when steamed, so there are options.

tshewman

Can also blanch in the bag via sv and maintain all of he nutrients. :-) I agree re the steaming and microwave, although this doesn't increase absorption (I'm splitting hairs here), but rather makes the nutrients more available for absorption. The latter depends on our personal biochemistry. Please don't misunderstand, i don't disagree with what I think you are saying.

Samuel__253807

Blanch in-a-bag in sous-vide, really?

I will have to look that one up.

I favour the microwave method as it's easier, but will have to experiment..

Samuel__253807

The information I have found varies when microwaving to blanch, but I have the following I would appreciate feedback on:

1. blanch kale / spinach in microwave wet after washing with a paper towel cover until the leaves turn a deep green colour.

2. blanch kale / spinach in microwavable dish water bath for 2mins.

3. extract plant-food and place into iced water for 1min.

4. drain water from blanched spinach and place on baking tray, placing paper towels beneath and on top, then leave in the fridge to extract remaining water.

5. Freeze in portioned bags.

I am concerned about the cooking times, but I know that can vary with a microwave. I have an 800W microwave, it also doesn't have a turntable, so I'll have to observe it.

Any suggestions?

ParkPrince_594359

Is that true? I wonder...

Samuel__253807

You may well be right to be skeptical, the relevant research papers I found concluded against the advice I'm prepared to take:

https://www.ncbi.nlm.nih.gov/pubmed/16496573

http://www.jstor.org/stable/10.1086/501694?seq=1#page_scan_tab_contents