Attempt to cross-link feruloylated arabinoxylans and proteins with a fungal laccase

A fungal laccase from Pycnoporus cinnabarinus was used to study the effect of proteins in the oxidative gelation process of wheat hour water-extractab le feruloylated arabinoxylans (WEAX), in an attempt to provoke a covalent c ross-linking between arabinoxylans and proteins. Capillary viscometry, spec trophotometry, SE-HPLC and RP-HPLC were used. Two different proteins were t ested: high molecular weight glutenin subunits (HMW-GS) and bovine serum al bumin (BSA). BSA was used in both native or oxidized (oxBSA) and reduced (r edBSA) forms, and HMW-GS in reduced form. Whereas oxBSA had no effect in ge lation, both HMW-GS and redBSA, provoked a delay on the arabinoxylan thicke ning and in the oxidation of feruloyl groups, in the presence of laccase. T his effect is attributed to the sulfhydryl groups of the reduced proteins. (C) 1998 Elsevier Science Ltd.. All rights reserved.