29C-5

 

Pentosans are cell wall, non-starch polysaccharides that play a major role in water absorption during dough formation.  The majority of pentosans are comprised of arabinoxylans.  Arabinoxylans exist in two forms: water-extractable and water-unextractable.  Both of these types can be further converted into solubilized arabinoxylans.  Water-extractable arabinoxylans and solubilized arabinoxylans impart positive attributes in bread and dough products (i.e. dough handling properties, stability, oven spring, loaf volume, and enhanced crumb structure), while water-unextractable arabinoxylans impart negative attributes.  Solubilization of water-unextractable arabinoxylans can be enhanced by the addition of specific enzymes called endoxylanases.  Endoxylanases may be used to improve the quality of wheat pasta and noodle products.

 

The objective of this research was to characterize changes in the rheology of extruded pasta dough by the addition of endoxylanase. 

 

Rheological properties of the dough were measured during extrusion in a single-screw extruder and in a capillary viscometer.  Enzyme concentration, temperature, flour variety (semolina and rye), moisture content, and incubation time were varied in order to characterize the effect of endoxylanases on the rheology of the dough.

 

Results from the single-screw extruder showed that extrusion pressure and shear viscosity decreased with increases in all variables studied; greater decreases were found in the rye flour dough as opposed to the semolina dough.  Enzyme concentration, incubation time, and extrusion temperature produced the most significant decreases.  Similar results were obtained with the capillary viscometer.

 

The addition of endoxylanase to pasta dough lowered the viscosity of the dough, which may result in improved processing conditions and higher gluten and starch yields.  Endoxylanases could be used in the production of low-moisture pasta doughs resulting in similar viscosities than those currently produced with high moistures.