yeah. afaik, cultivar/terroir is what affects w-6 levels. Processing means less polyphenols. Is there evidence that low quality olive oil has different fatty acid ratios?
Was that what you meant to say? Low-quality olive oil is HIGH in w6, and is a lousy neutral-tasting oil.
low quality olive oil is low in w-6 and probably the best neutral tasting oil if you don't want saturated fat
You're quite right that cultivar, latitute, and climate affect fatty acid composition, and not processing -- though that of course cuts both ways, vis-à-vis your original statement that "low quality olive oil is low
in w-6". You're here clearly (and quite reasonably) using 'low-quality' to mean either processed (refined) olive oil, or unrefined oil that fails to meet the 'extra virgin' standard set out by the Int'l Olive Association. So, two things. First, even using that meaning, a lot of the higher-n6 oil is of low-quality by dint of origin: there's a lot of lousy olive oil being produced in Tunisia and other Middle Eastern countries (which is not to say that there isn't any good stuff being produced there), and the climate and local cultivars do conspire to make it higher in n6; eg, the main Tunisian olive cultivars, Chemlali and Chétoui, produce oils with oleic acid in the low-to-mid-60 percent range, and other cultivars produce at the low end of their genetic range when grown there. Second, and (to anticipate) precisely on health grounds, I would stipulate
an oil that had a high n6 or a low poly count to be, ipso facto, a low-quality oil, even if it were unprocessed and of very high quality by IOC standards, which don't include poly counts and only discriminate %oleic as part of screening for adulteration with seed oils, and thus permit oils as low as 55% oleic acid. (Yes, I know that this is a bit perverse: there are, eg, award-winning Arbequinas with very low poly counts indeed, and with %oleic too low for me to want to consume).
Typical supermarket olive oils, refined or no, have middling %oleic, because they are blends of oils sourced from a wide range of cultivars and geographic origins -- and certainly higher than most seed oils. Maybe that's all you'd meant; I took you to be saying that they would be high as olive oils go
. Sorry for any misunderstanding.
I also haven't seen anything indicating decomposition to glycerol & fatty acids is a health problem, which is the main distinguishing factor of evoo vs plain.
I agree that "decomposition to glycerol & fatty acids is a health problem", but (a) there are a lot more things distinguishing EVOO from virgin and lower-grades of unrefined OO than FFA, and most of them do have health impacts: peroxide value, conjugated dienes (K232) and carbonylic compounds (K270), ΔK, and even the taste panel, which picks up a lot of things organoleptically that you don't want to put into your body but for which there is no established chemical test (fermentation byproducts, yeasts and molds, etc)) that does have health impacts.
Finally, unlike EVOO (low FFA) and many lower-grade unrefined OOs (high FFA), paradoxically refined OO has ZERO free fatty acids, because they're removed by the refining process.
Edited by Michael, 17 May 2011 - 01:21 PM.