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Astringent facts for kids

Kids Encyclopedia Facts
AlumCrystal
A crystal of the astringent alum
Closeup of blackthorn aka sloe aka prunus spinosa sweden 20050924
The astringents and acids in fresh blackthorn berries (sloes) give the fruit its sourness.

An astringent (sometimes called adstringent) is a chemical that shrinks or constricts body tissues. The word derives from the Latin adstringere, which means "to bind fast". Calamine lotion, witch hazel, and yerba mansa, a Californian plant, are astringents.

Astringency, the dry, puckering mouthfeel caused by the tannins in unripe fruits, lets the fruit mature by deterring eating. Ripe fruits and fruit parts including blackthorn (sloe berries), Aronia chokeberry, chokecherry, bird cherry, rhubarb, quince and persimmon fruits, and banana skins are very astringent; citrus fruits, like lemons, are somewhat astringent. Tannins, being a kind of polyphenol, bind salivary proteins and make them precipitate and aggregate, producing a rough, "sandpapery", or dry sensation in the mouth. The tannins in some teas and red grape wines like Cabernet Sauvignon and Merlot produce mild astringency.

Uses

In medicine, astringents cause constriction or contraction of mucous membranes and exposed tissues and are often used internally to reduce discharge of blood serum and mucous secretions. This can happen with a sore throat, hemorrhages, diarrhea, and peptic ulcers.

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