Skip to main content
ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Research » Publications at this Location » Publication #114744
Title: IDENTIFICATION OF 4-0-5 COUPLED DIFERULIC ACID FROM INSOLUBLE CEREAL FIBER

Author
item Ralph, John
item MARITA, JANE - U OF WISCONSIN MADISON
item BUNZEL, MIRKO - U HAMBURG GERMANY
item STEINHART, HANS - U HAMBURG GERMANY

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/22/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Cereals provide dietary fiber, an important nutritional commodity used for human/animal foods. We have found that so-called "ferulates" in plant fiber cross-link polysaccharides in plant cell walls providing structural strength but limiting the availability of the polysaccharides for digestion by the animal. The presence of cross-linked ferulates in cereals has not currently been addressed. During a deeper study into the amounts and distribution of cross-linked ferulates in a range of cereal fibers we discovered, as reported here, a type of cross-linked ferulate which we had anticipated from synthetic laboratory work but had not yet seen in plants. The identification is mainly of scientific interest, completing the spectrum of cross-linked ferulates found in plants, supporting the role of the product in cell wall cross-linking reactions in fibers, and identifying basic mechanisms of cross-linking. Such studies are aimed at providing basic knowledge allowing an understanding of limitations to digestibility, and providing a basis for improving plant utilization and agricultural sustainability.

Technical Abstract: The extracts of saponified cereal fibers of whole grains of corn (Zea mays L. convar. microsperma), wheat (Triticum aestivum L.), spelt (Triticum spelta L.) and rice (Oryza sativa L.) were investigated for dehydrodimers of ferulic acid using gas-liquid-chromatography (GLC) with mass spectrometric detection (GLC-MS) and flame ionization detection (GLC-FID). In addition to the 8-5-, 8-8-, 5-5- and 8-O-4-coupled diferulic acids previously identified from other plant materials the 4-O-5-coupled diferulic acid (E)-3-{4-[(E)-2-carboxyvinyl]-2-methoxyphenoxy}-4-hydroxy-5-methoxycinnamic acid (4-O-5-DFA) could be identified in all fibers investigated. The new diferulate was authenticated by comparison of its mass spectrum and its relative GLC retention time with those of the synthesized compound. Semiquantitative determination of 4-O-5-DFA showed that it is present at 8-30 micro g/g, approximately 70-100 times lower concentrations than the sum of 8-5-coulpled diferulic acids, the major diferulic acids in the investigated fibers.