An Attempt to Identify the Low Molecular Feruloylated Oligosaccharides in Beer

Ferulic acid (4‐hydroxy‐3‐methoxycinnamic acid), predominantly in ester form in arabinoxylan chains, is the main phenolic acid present in barley and malt. Only about 1% of the total ferulic acid in barley is present in the free form. A number of previous works concerned the contents of free and esterified ferulic acid in a broad range of popular beers, but there is little information about the possible composition of feruloylated oligosaccharides in beers. The aim of this preliminary work was to purify the feruloylated oligosaccharides from lager beers (by the means of preparative chromatography) followed by composition elucidation using TLC, HPLC with RI or UV detection and ¹H‐NMR. Indeed, the qualitative analyses of isolated fractions from beer revealed that the fractions contained ferulic acid in the ester form (as proven after mild alkaline hydrolysis). It was also shown that molecular masses of oligosaccharides present in the purified beer fractions were similar to the masses of arabinose and xylooligosaccharides in the range of xylose to xylohexaose. Although a number of purified beer samples contained oligosaccharides of higher molecular masses, these were not further characterized. Taking under consideration the presented results, it can be concluded that beer can be a good source of feruloylated oligosaccharides, significant in the context of human health benefits.