Hi
Sorry, I think a misunderstanding happened, I couldn't find that clear meaning (which clearly defines the taste) in OALD, CALD or LAAD. I found these meanings for astringent:
Cambridge Advanced Learner's Dictionary: severe, describes something that acts as an astringent (astringent: a drug or cream that causes the skin or other tissue to tighten so that the flow of blood or other liquids stops).
Longaman Advanced American Dictionary: 1. criticizing someone very severely. 2.able to make your skin less oily or stop a wound from bleeding 3. having an acid taste like a lemon. (it doesn't exactly clarify it dries the tissues, makes a contraction and draw together the tissues)
Oxford Advanced Learner's Dictionary: (the third meaning) of a taste or smell, slightly bitter but fresh.
I think the ones that I found and mentioned before clarifies this meaning better.
Could you kindly help me and tell me if it can be a good word to refer to the taste of an unripe persimmon? Does it sound natural to you as an English native speaker?
Thanks a billion.