Release of ferulic acid from cereal residues by barley enzymatic extracts

The use of esterase- and xylanase-rich extracts of barley for the release of ferulic acid (FA) from barley spent grain and wheat bran is proposed here. Esterase activity was determined in 11 barley varieties and enriched extracts were prepared from one of the varieties with higher activity, Halcyon (7.3 mU/g barley). The esterase(s) extract alone was able to release low amounts of FA from spent grain and wheat bran. However, the presence of the xylanase(s)-containing extract increased the release of FA and demonstrated synergistic reactions between these enzymes. Maximum FA released by the combination of esterase(s): and xylanase(s) extracts was 26% and 13-3% from spent grain and wheat bran respectively after 36 h incubation. FA from spent grain and wheat bran was also released by barley esterase(s) extract and Trichoderma viride xylanase. Reducing sugar release followed a pattern similar to that for the release of FA. However, barley xylanase(s) appear more specific than T. viride xylanase for spent grain. These results demonstrate the potential use of economical barley, enzymes for the release of ferulic acid from cell wall materials.