What is the fragrance in Puerto Rican fired food?

[LAS1414]

We recently spent 10 days in Puerto Rico. I was aware of a common fragrance from fried food wherever we went. Upscale and home cooking restaurants. I went to a local grocery store to look at cooking oils, but they were just the expected canola, corn and.... hmmm.... senior moment.

Does anyone recognize what I'm referring to?

Can anyone tell me what causes this?

TIA
LAS

[Dib's]

I have no idea what that scent could be. Was there anything specific, like "fried chicken" being cooked or was it all fried food?

[LAS1414]

I don't think it was associated with specific foods, unless it was the batter/bread used to enclose things. I smelled it all along the 60 kiosks in Luquillo, for instance, and at various restaurants. It wasn't a strong fragrance. It was akin to the "fried food" fragrance you smell here at any fast food place like MacDonald's, Burger King, etc. Very subtly different. That's why I went researching cooking oils. Might restaurants use, say, palm oil, but home cooks not?

TIA
LAS

[Dib's]

Could it have been the Arepas? (fried bread everything-or so it seems-is served?)

[LAS1414]

I'm afraid I've identified it. The other day some mushrooms I was frying gave off an off smell. I thought, "this smells like Puerto Rico!" My husband agreed about the smell, and we figured out that the canola oil I was using was in an almost empty bottle he'd found at the back of a deep cupboard.

I'm now convinced it's simply rancid oil.

[Dib's]

Ewwww, yuck! Think of it as they used "older, mature oil". I would