On Fri, 23 Aug 2002 00:37:38 -0500, Wendy Hubbard <[log in to unmask]> wrote:

>I have a question about Omega 3 stability.  I see frequent discussion about
>how unstable the O3's are, so wouldn't they be destroyed by cooking
>heat?  Yet we talk about cooking all of these foods and eating them for
>their O3 content.

I have read (at Udo Erasmus I think) that fats, particularly EFAs are
suspect to damage in heat, but *not* in temperatures below 100 deg C
(that's the max temperature reached when cooking in water).
Heat transformations seem to occur only over 140 or 150 deg C,
and at longer time (from >20 minutes I think).
Such high temperature will be reached when frying in a hot pan (no water)
and that's why we shouldn't fry with oils containing EFAs.

The deterioration of EFAs is normaly oxidation (rancidness), which occurs
slowly with the time and is amplified by exposure to light and even as low
temperatures like room temperatures.

So, cooking would be ok, frying might be a problem,
but keeping the oils for a longer time will be a problem.
Particularly in exposure to light and the quicker, the warmer it is.

regards

Amadeus