EXTRACTION AND CHROMATOGRAPHIC SEPARATION OF TANNIN FRACTIONS FROM TANNIN-RICH PLANT MATERIAL

wheat, buckwheat groat, hazelnuts, walnuts, and almonds using 80 % (v/v) acetone. The tannin fractions were separated from the crude extracts using Sephadex LH-20 column chromatography with ethanol and 50 % (v/v) acetone. The tannin fractions were characterised by colour reaction with vanillin/HCl reagent and ability to bovine serum albumin (BSA) precipitation. The yield of extraction of phenolic compounds ranged from 3.77% (buckwheat) to 17.20 % (walnuts). The content of tannin fraction in the crude extracts was differentiated and ranged from 10.5 % (faba bean) to 45.5% (broad bean). The tannin fraction from buckwheat possessed the highest content of tannins determined using vanillin method (1.04 absorbance unit at 500 nm/mg) whereas the lowest content was noted for broad bean (0.066 absorbance unit at 500 nm/mg). In the model system, the highest amount of BSA was precipitated by tannin fraction of hazelnuts, whereas the lowest was noted for adzuki bean.