EXTRACTION AND CHROMATOGRAPHIC SEPARATION OF TANNIN FRACTIONS FROM TANNIN-RICH PLANT MATERIAL
 
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Pol. J. Food Nutr. Sci. 2007;57(4):471–474
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ABSTRACT:
The crude phenolic extracts were obtained from red bean, adzuki bean, red lentil, green lentil, broad bean, faba bean, field bean, vetch, buckwheat, 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 17.2% (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.