Found it. From a post of mine 3 November 2021 in the What Have You Been Reading thread:
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Right.
The reference in Memory that I was referring to comes early in chapter 16, page 261, location 4610 on the kindle. Mahit is thinking ''she likes the taste of processed fish-flake powder on her breakfast porridge and they are repulsed'',
My brain immediately flashed to an early scene in Cyteen. Chapter 2, part ii, Ari Senior is dining with the Family: "Ari smiled gently across the table, across the salad with vinaigrette, product of their own gardens, and dusted it liberally with a spoonful of Keis, synthetic cheese, a salted yeast, actually: spacer's affectation. Her mother had used it. Ari still liked the tang of it, and imported it downworld at some little trouble. Most of the Family abhorred it.
Well, maybe it's just me, but that's how my brain works sometimes. So it goes.