Compositional Changes and Baking Performance of Rye Dough As Affected by Microbial Transglutaminase and Xylanase.

Doughs supplemented with endoxylanase (XYL) and varying amounts of microbial transglutaminase (TG) were analyzed by sequential protein extraction, quantitation of protein fractions and protein types, and determination of water-extractable arabinoxylans. With increasing TG activity, the concentration of prolamins and glutelins decreased and increased, respectively, and the prolamin-to-glutelin ratio strongly declined. The overall amount of extractable protein decreased with increasing TG level showing that cross-linking by TG provided high-molecular-weight protein aggregates. The decrease of the high-molecular-weight arabinoxylan fraction and the concurrent increase of the medium-molecular-weight fraction confirmed the degradation of arabinoxylans by XYL. However, XYL addition did not lead to significant improved cross-linking of rye proteins by TG. Volume and crumb hardness measurements of bread showed increased protein connectivity induced by XYL and TG. Significant positive effects on the final bread quality were especially obtained by XYL addition.