Do centrifugal juicers destroy vitamins through friction?

Question

I've read that in a couple of places.

Answer

There are two explanations usually given for why centrifugal juicers lose some of the nutritional value:

• frictional heating, supposedly from the higher speed of the moving parts (although it's never clearly explained where this comes into play, maybe from the juice splatting on the container)
• aeration of the juice (since there's usually more frothing with a centrifugal juicer), which causes the juice to oxidize more and faster.

This page is fairly typical of the explanations.

I'm personally not convinced that either of these is a huge issue, but OTOH I do like the twin-gear masticating juicer we have because it can juice anything and doesn't suffer from those supposed disadvantages of the centrifugal type.

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