Ferulic acid

• 4- hydroxy-3- methoxycinnamic acid
• Conifers acid

Yellowish, odorless solid

Fixed

1.14 g · cm -3

169-173 ° C

Soluble in water

Attention

Template: Infobox chemical / molecular formula search available

Ferulic acid (more precisely trans-ferulic acid ) is an organic compound (or their esters ) in different plants (eg Stinkasant, dill, rice, grasses ) occurs. See also the genus Ferula. It plays a role in the synthesis of lignin in the cell walls of plants.

Chemical Properties

Ferulic acid belongs to the group of phenolic acids. From their structure, among others, the curcumin of turmeric comes from. Of course, you are generally only in the trans form. Only beans contain a higher proportion of cis -ferulic acid, which some researchers assume that the cis form is created only for the storage of plant samples.

Use

Ferulic acid used as the starting material for the preparation of vanillin and antimicrobials for soaps, perfumes and cosmetics.

Importance in the preparation of beer

Ferulic acid has, particularly in the wheat beer production, a major influence on subsequent sensory characteristics of the beer.

Occurrence of ferulic acid: The ferulic acid is bound in the malt to the insoluble pentosans, there to arabinose side chains. Barley has as wheat a higher proportion of bound ferulic acid, are analogous to higher values ​​in Gerstenmalzwürzen ago.

Influence during mashing: During mashing is the biggest influence on the release of ferulic acid ( malting only by hydrolytic Pentosanabbau ). Cheap Einmaischtemperaturen of 37-47 ° C cause a significant increase in ferulic acid, 44 ° C represents result of the degradation of arabinoxylan by the endo-and exo - xylanases (optimum 45 ° C) and arabinosidases (40-45 ° optimum temperature C) is released ferulic acid. A reduction in the mash pH below 5.7 causes a slowing of degradation.

Fermentation: Top yeast has the property to form from the ferulic acid as a precursor of the 4- vinylguaiacol, which is a typical wheat beer aroma, reminiscent of clove. During fermentation, the 4- vinylguaiacol is by decarboxylation of ferulic acid formed in wheat beer yeast in amounts of about 0.5-3.0 ppm. The formation is due less to the usual temperatures of 15-25 ° C fermentation rather than on the vessels and Hefeführungen used. A multiple Hefeführung by harvest standing zylinderkonischen fermentation tank has a negative influence on the formation of 4- Vinylguajacols by increased static pressure, which also commonly affects the formation of the ester and stress on the yeast cell. Desirable area of ​​the formed 4- vinylguaiacol is 1.2-1.7 ppm.