Evaluation of physicochemical properties of gluten modified by Glucose oxidase and Xylanase
The effect of Glucose oxidase (GOX) and Xylanase (XYL) on gluten-starch separation and physicochemical
properties of gluten was studied. The gluten yield and Rmax increased and the extensibility of gluten and
the amount of free sulfhydryl groups (SHf) decreased in comparison to the control with the addition of
GOX up to 80 ppm. These observations indicated the high strength of gluten network by 80 ppm of
enzyme. GOX caused a shift to larger particle size distribution of glutenin macropolymer (GMP) gel. Here,
GMP gel at low enzyme level was more elastic and stiffer. Generally, an improvement of GMP gel quality
can be obtained by the addition of GOX, although inverse effects were obtained when excessive enzyme
levels were added. The results indicated that XYL leads to increase the tendency to aggregate by
degradation of pentosane and decreasing the viscosity. The enzyme led to decrease the particle size
distribution in GMP gel. In these samples, a tendency to increase the amount of SHf content was
observed and it seems that the incorporation of pentosan and protein prevented the disulfide crosslinking.
GMP gel separated with XYL had higher delta value and lower storage modulus in comparison to
GMP gel separated without XYL.