Will fruits and vegetables be less oxidized if blended at higher speeds for shorter periods of time, or at lower speeds for longer periods of time?

Do the oxidized molecules in vegetable juice oxidants?

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    $\begingroup$ What is your last sentence supposed to mean? $\endgroup$ – Mithoron Jan 30 '19 at 1:30
  • $\begingroup$ Oxidation occurs due to exposure to oxygen in the air (or in the case of vegetables, also due to cell damage followed by enzymatically catalyzed breakdown processes). If you moosh a banana it will oxidize faster than an unmooshed one, thus you would suppose blending it for an extended time will increase the extent of the oxidation process. $\endgroup$ – Buck Thorn Jan 30 '19 at 12:16
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    $\begingroup$ Ok, granted this is actually not a trivial question, as food scientists would surely note. In general you can slow the rate of oxidation by keeping things cold (as one posted answer indicates), and mechanical rupture with a blender will heat your fruit, elevating the temperature. My guess is the oxidation is very fast, on the order of seconds, so that if you want to achieve a certain level of homogeneity you're better off doing it cold and slow (but not too slow). You can also add lemon juice or vitamin-C to impede oxidation. $\endgroup$ – Buck Thorn Jan 30 '19 at 15:05
  • $\begingroup$ The breakdown due to enzymatic activity is more difficult to interfere with and I'd have too look into this more. In the lab all sorts of enzyme inhibitors are available to interfere with this. $\endgroup$ – Buck Thorn Jan 30 '19 at 15:07

The higher the RPM and the longer the time, the faster your fruits will be oxidized

The oxidation is a chemical reaction that occurs when something reacts whit oxygen (a molecule, an atom, etc...) and as any chemical reaction the more divided the reactants are, then the faster the reaction will be.

That’s why usually the detergent for the washing machine comes as a powder, so it can be easily dissolved, while the soap are in a solid and robust bulk, so it can be used in a controlled way for a longer period of time. In your case I’m sure that the higher the rpms for blending the fruit, the smaller the pieces will be. And if in addition you let them exposed to the air for a long period of time, then they’ll surely oxidize really fast. So I will recommend you to blend them at slow rpm and once they are small pieces, protect them, keeping them inside a closed recipient in the fridge. The important thing here is that if it’s possible don’t turn the fruit into puree, if you still can use them as small pieces and is very important that the fruit does not gets oxidized, then I suggest you to use a knife or something similar. If oxidation is not critical, then just blend them and use them as quick as you can, you won’t notice the difference.


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