Ferulic acid and its position among the phenolic compounds of wheat.

Ferulic acid (3-methoxy-4-hydroxycinnamic acid) is the main phenolic acid occurring in cell walls of monocotyledones. Due to its blue-and-white fluorescence it is easily identified and is located in the cereal grain morphological parts. Its 40-fold greater concentration was found in the cells walls of the seed coat and aleuronic layer than in the cells walls of endosperm. Most often, it is linked by ester bonds with hemicellulose chains, mainly with arabinose residues and it also polymerizes with lignin through ether bonds. However, ferulic acid in the pentosane molecules forms specific complexes with proteins through chemical bonds with amino acids. It is interesting to mention the theory of the pentosane gel formation in which a great role is assigned to ferulic acid. An oxidized form of ferulic acid-diferulic acid-produces gel formation by linking two pentosane or protein molecules. The blue-and-white fluorescence of ferulic acid can be applied to determine flour contamination with grain coat particles and its ability to form complexes with pentosanes and proteins is important in the formation of dough texture with its semi-elastic properties.