The article actually says that sour receptors detect ammonium chloride. This means that there is no new taste. For there to be a new one, there would need to be a kind of receptor which is activated while the rest of them are inactive.
https://www.nature.com/articles/s41467-023-41637-4
I would have thought this is about how tasting sour works not about a completely new taste.
> baseless
heh.