PROPERTIES AND PRECURSORS OF HORDEUMIN PRODUCED FROM UNCOOKED BARLEY BRAN BY ETHANOL FERMENTATION

Hordeumin (a purple pigment) formed by the ethanol fermentation of uncooked barley bran had properties partially different from those of conventional anthocyanins and showed high molecular tannin-like properties. When the polyphenol constituents (containing proanthocyanidins) in barley bran and the fermented filtrate were removed, the amount of the pigment formed was reduced. Hordeumin was decomposed to lower molecular weight substances and anthocyanidins (cyanidin and delphinidin) by acid hydrolysis. On the other hand, the anthocyanidin components formed by acid hydrolysis of the polyphenol constituents in barley bran and the fermented filtrate coincided with those of hordeumin. The precursors of hordeumin were proanthocyanidins contained in barley. Hordeumin seems to be a novel pigment with a high molecular weight having the properties of anthocyanin pigment.