Content of (+)‐catechin and proanthocyanidins in barley and malt grain

Abstract Acetone:water (3:1) extracts of milled barley grains contained simple monomeric, dimeric and trimeric flavanols in addition to higher molecular weight flavanoid tannins. Whereas (+)‐catechin and the simple individual oligomeric proanthocyanidins were readily separated by h.p.l.c. and t.l.c. fine resolution of the tanning components was not accomplished. Adsorption chromatography on Sephadex LH‐20 permitted group separation and measurement of tanning components which were characterised as polymers of (+)‐catechin and (+)‐gallocatechin. Using h.p.l.c. little change in the contents of simple flavanols was detected during the malting of barley, neither were there substantial differences in flavanol contents between five different varieties of barley. The tannins appeared to be formed in the grain prior to harvesting, possibly by oxidation of simple flavanols, and were not artefacts of post‐extraction treatments.