non-tannin
That portion of the water-soluble matter in a
vegetable tanning material, other than the tannin,
that is non-volatile. Non-tannins, or nontans, as
they are usually called, may include hydrolysis
products of the tannins, starches, gums,
hemicelluloses, polysaccharides, hexoses,
pentoses, uronic acids, organic acids, including
lactic and acetic, together with their salts,
inorganic salts, proteins and zymoproteins
(enzymes), if the temperature is not too high, as
well as coloring matters such as brasilin,
fisetin, and quercetin. (248 , 291 , 306 , 363 )