Amadeus Schmidt wrote:
>
> Recently Todd mentioned that he doesn't expect trans-fatty acids from
> frying.

It may depend on what you mean by "frying." I always use olive oil
when pan-frying or sautéing meats and vegetables. I don't expect such
brief, gentle cooking to degrade the oil significantly. Repeatedly
reusing olive oil in a deep fryer until it turned dark brown would
clearly be another matter.

Here's a link to a UN publication on high temperature processing of
oils, which shows that the conversion to trans is time and temperature
dependent. Look at Figure 5.2 for graphical results of tests on four
different oils. The URL is long; you may have to copy and paste:

http://www.fao.org/docrep/V4700E/V4700E0a.htm#Potential side reactions
during high temperature processing

One thing to note is that none of the oils starts with 0.0% trans
content. Another is that all the oils are stable for hours at 220
degrees C (428 degrees F).

Bill