Arabinoxylan gels: impact of the feruloylation degree on their structure and properties.
Arabinoxylan (AX) samples of decreasing ferulic acid (FA) contents were chemically prepared from water-extractable wheat arabinoxylans without affecting their other structural properties. Gels were obtained from these partially feruloylated WEAX (PF-WEAX) by enzymatic covalent cross-linking of FA leading to the formation of diferulic (di-FA) and tri-ferulic acid (tri-FA). WEAX gelling ability was found related to the WEAX FA content whereas the gel structure and properties depended on the density of newly formed covalent cross-links. FA content of WEAX ranging from 1.4 to 2.3 microg/mg AX gave gels with di-FA cross-links contents from 0.20 to 0.43 microg/mg AX and G' values from 5 to 44 Pa. For WEAX gels with initial FA contents from 1.6 to 2.3 microg/mg AX, average mesh size ranging from 331 to 263 nm were calculated from swelling experiments. Cross-linking densities of gels, determined from swelling experiments, were higher than those that could be theoretically estimated from the di-FA and tri-FA content of WEAX gels. This result suggests that, in addition to di-FA and tri-FA, higher ferulate cross-linking and physical entanglements would contribute to the final WEAX gel structure.
Carvajal-Millan
Elizabeth
E
U.M.R. Ingénierie des Agropolymères et des Technologies Emergentes, ENSAM/INRA, UMII/CIRAD, 2 Place Pierre Viala 34060, Montpellier Cedex 1, France.
Landillon
Virginie
V
Morel
Marie-Hélène
MH
Rouau
Xavier
X
Doublier
Jean-Louis
JL
Micard
Valérie
V
D002240:Carbohydrate Sequence; D003373:Coumaric Acids / Q000737:chemistry* / Q000302:isolation & purification; D005782:Gels; D008969:Molecular Sequence Data; D015394:Molecular Structure; D013997:Time Factors; D014990:Xylans / Q000737:chemistry*
D003373:Coumaric Acids; D005782:Gels; D014990:Xylans; C085118:arabinoxylan; C004999:ferulic acid