Word for the flavor found in green bananas or green persimmon [duplicate]

Solution 1:

Astringent

Astringent is a taste that puckers the mouth, numbs the tongue, and constricts the throat. This taste is caused by astringents such as tannins.

The astringent taste is in unripened bananas, unripe persimmons and cashew fruits.

Astringent (taste) - Wikipedia

Solution 2:

I think the closest answer is tannic, which comes from tannins:

A yellowish or brownish bitter-tasting organic substance present in some galls, barks, and other plant tissues, consisting of derivatives of gallic acid.

(Copied from Lexico)

I believe the sensation from green bananas is produced by a similar process as tannins in red wine. For me that is a particularly unpleasant feeling that makes me grimace and pull my lips over my teeth.

It can easily be confused with bitterness but is quite different from the sourness of lemons, etc.

So, you could say

These green bananas are very tannic.