So, wonders Aviatrix, what's erucic acid and why is it bad? Wikipedia says it's a straight chain of twenty-two carbon atoms with the COOH you'd expect of an organic acid tacked on one end. It's "monounsaturated" which means it's two hydrogen atoms short of being fully hydrogenated. Which is bad for me again, saturated or unsaturated oils? New diversion ... oh this is complicated, no wonder I didn't remember. Unsaturated fats, that is the ones with double bonds that leave room for more hydrogens, are "good" because they lower bad cholesterol, but apparently they are "even better" if they are monounsaturated, having only one double bond and thus room for only two more hydrogens, because otherwise they might lower good cholesterol, too. The "bad" fats are the saturated ones, all full up with hydrogens, and having no double bonds, because they are solid at room temperature and clog your arteries.
(It's vaguely implied that the solidity is what clogs your arteries, but surely they don't escape the digestive process and make it through the alveolae into the blood with the hydrocarbon chain intact? Maybe I should have taken more biology. If what I eat is really racing around in my blood intact, maybe I should eat fewer Girl Scout cookies. They have kinda scary ingredients.) Finally, we have the "really bad" fats, the trans fats. I think there was even a Family Guy episode about how bad trans fats are. They are produced by hydrogenation, but wait a moment. I know what trans means in a chemical context. It means that the two hydrogens either side of a double bond are on opposite sides of the chain. So trans fats have to be unsaturated. So the "really bad" fats are necessarily members of the "good" or "even better" camps? The depiction of erucic acid structure on Wikipedia shows a cis structure (the opposite of trans). So we're safe.
But wait, why was erucic acid bad for me again? It's present in kale, mustard, brussels sprouts and broccoli, all of which are supposed to be good for me. It tastes bad. It might be bad for rats, because they can't metabolize fats well at all. There's some evidence it causes heart problems, and other evidence it cures them, as well as curing some weird rare disease. I give up on erucic acid.
Maybe the glucosinolates are really the evil part. Glucosinolates occur in almost all plants and react with a plant enzyme to protect the plant from insect attacks. Like everything else that does anything, a little is good, apparently protecting against cancer but a lot is bad, suppressing thyroid function and changing animal behaviour. So okay, too much is bad.
Anyway both compounds are bitter-tasting so they bred them out and then rebranded the result as canola. According to the canola marketing association website they did this, to differentiate the superior low-erucic acid and low-glucosinolate varieties and their products from the older rapeseed varieties, but yeah, right. I'm sure the person doing family grocery shopping in 1978 was far lass likely to balk at an association with glucosinolates than at the word rape. The can is for Canada and ola for oil, or oil low acid, but I've heard the homophony with love, peace and health food granola wasn't entirely coincidental.
Now most of the crop is GM and Roundup Ready and hey look it's pretty and yellow. So, uh, now I have more to think about when I see the bright yellow fields of canola sliding away beneath my wings.
My descent checklist is also colour-coded yellow. Fuel selectors on fullest tanks, anti-ice not required, altimeter set, oxygen off through 10,000', radios set, there's no ATIS so call flight services for the aerodrome advisory. Hmm, here one normally taxies off via the cross runway, but today the cross runway is closed, so everyone has to backtrack to the apron. It's a busy airport, so we all have to space ourselves out and hustle back to the beginning of the runway to give the following aircraft their turn.
I can't see anything wrong with the cross runway. It turns out they're just mowing the grass beside it. Sometimes there are crops grown on the infield at the airport, but I'm pretty sure this is just ordinary grass. Definitely not canola.