Extraction and assay of ferulic acid esterase from malted barley

Ferulic acid esterase activity was detected in extracts of barley malt usin g an assay employing a novel artificial substrate, mono-feruloyl glycerol. Mono-fercrloyl glycerol has been synthesized and analysed to determine its degree of substitution and purity. It consists of a mixture of the two isom ers 1-feruloyl glycerol and 2-feruloyl glycerol. The extraction of ferulic acid esterase and its assay conditions have been optimised. The presence of both a detergent and reduced glutathione in the extraction medium increase d the amount of enzyme extracted. A pH of 7.5 was optimal for enzyme activi ty. The enzyme in solution was only stable up to 30 degrees C. The crude ex tract containing the enzyme released free ferulic acid from both soluble an d insoluble cell wall materials. After extraction of the soluble enzyme, in soluble enzyme, capable of releasing free ferulic acid from feruloyl glycer ol, was detected in the residual grain solids.