(2) hydrolysis - identification test

polyhydric phenols

tannins, when hydrolysed, yield relatively ____

pyrogallol

gallic acid → _________

catechol

protocatechuic acid → _________

organic solvents

tannins are soluble in water, dilute alcohol, alkalis, and acetone; sparingly soluble in ____

gelatin

tannins causes precipitation of ________ as well as alkaloids

Cu, Pb, Sn

tannins are precipitated by salts of , _________ and aqueous solution of potassium dichromate

precipitate proteins

___________ from solution and can combine with it which renders the protein resistant to proteolytic enzymes

colloidal solution

tannins with water forms _________

sharp puckering taste

taste of tannins

antiseptic and astringent

Their ability to precipitate proteins makes them an ______ and ________

leather

Utilized in the process of vegetable tannins thus converting animal hides to _____

feeding deterrent

tannins produced by a plant as a _________________ , as their binding to protein may reduce the dietary value of the plant as a food

astringent

tannins are _________ in both GIT and skin abrasions

tanning leather

tannins are used in _______________ because of their ability to combine with proteins of animal hides

alkaloidal poisoning

tannins are used as an antidote for _____ because of their ability to precipitate alkaloids from solutions of their salt forming an insoluble tannate

inks / dyes

tannins are used in the manufacture of ______ because they form deeply colored compounds with iron salts

gelatin
proteins
alkaloids

solutions of tannins are used in the laboratory as reagents for the detection of ________

• Astringent

• Antiseptic

• Anti-diarrhea

• diuretics

• Anti-tumor (stomach and duodenal)

• Anti-inflammatory

• Anti-oxidant

• Hemostatic agent

medical uses of tannins

maceration

soaking

decoction

• Soaking with the application of heat or with boiling

• Solvent alcohol or water

organoleptic test

Determine the color, odor, appearance, and physical state of the tannin

brownish-color

color of tannin extract

pungent odor

odor of tannin extract

sharp, puckering taste

taste of tannin extract

amorphous, non-crystalline

state of tannin extract