Final answer:
The astringent taste of fruit and vegetables is caused by tannins, which are bitter-tasting molecules that serve as a defense for the plant.
Step-by-step explanation:
The astringent taste of fruit and vegetables (F/V) is primarily the result of the component called tannins. Tannins are a group of bitter-tasting molecules which include alkaloids that are nitrogen-containing compounds found in various plant products.
These compounds serve as a defense mechanism for the plant by making them less appealing to herbivores and less susceptible to microbial infections. Other primary tastes that humans detect include sweet, sour, salty and umami but these are not associated with the astringent taste of tannins.