301 Understanding arabinoxylan and endoxylanase functionality in breadmaking: Predicting and monitoring endoxylanase functionality.

C. COURTIN, H. Van Den Broeck, and J. A. Delcour. Katholieke Universiteit Leuven, Laboratory of Food Chemistry, Kardinaal Mercierlaan 92, Heverlee, B-3001, Belgium.

Recent research, combining wheat fractionation and reconstitution techniques with in vitro endoxylanase degradation of different arabinoxylan fractions, led to the hypothesis that endoxylanases improve loaf volume mainly by converting water unextractable (WU AX) in water extractable arabinoxylan (WE-AX) or, more specifically, by decreasing the level of WU-AX and increasing the level of WE-AX. To test this hypothesis, an experimental setup was designed. A series of endoxylanases were screened in vitro for their specificity towards WE-AX and WU-AX. Two endoxylanases with markedly different specificities and one with intermediate features were selected and added to the bread-making process in different concentrations. Dose-response (bread volume) curves were constructed. The AX-population was monitored throughout the process and at different enzyme concentrations. The results increased our understanding of AX functionality in breadmaking.