Studies On The Application Of GOD And TGase In Frozen Doughs

This paper mainly investigated improvement of wheat flour quality by glucose oxidase (GOD) and transglutaminase (TGase), effect of them on rheological and micro structural properties of frozen doughs, influence of them on frozen dough stability during storage, and effect of them on wheat dough proteins.In farinograph, the showed that the addition of GOD and TGase did not change significant the water absorption, but development time, stability time, width of curve increased. Addition of GOD and TGase increased the content of wet gluten. Aveographic parameters were determined using an alveograph. Dough with GOD the extensibility (L) decreased. Conversely, GOD addition increased the tenacity (P), curve configuration ratio (P/L), deformation energy (W) and spring index (Ie). But the addition of GOD destroyed dough tenacity when overadditiving. The addition of TGase led to increase of the tenacity, the extensibility, deformation energy, and spring index (Ie). TGase had the function of an emulsification and oxidation. TGase was able to improve the properties of dough process.The effects of GOD and TGase on parameters of RVA were investigated using a rapid visco-analyser (RVA). The addition of GOD and TGase in wheat flours decreased hot paste peak viscosity, trough viscosity and final viscosity.The effects of GOD and TGase on rheological properties of doughs were studied using a dynamic rheometer and Brabender Extensographr. The addition of GOD and TGase increased the elastic modulus and the viscous modulus. The elastic modulus was higher than the viscous modulus at any given frequency or time. The results showed that after frozen storage the elastic modulus of the dough decreased. However, the elastic modulus was the lowest for control dough (without any additives) and the highest for dough with GOD for each storage period. As frozen storage increasing, Resistance to extension (R) reduced, Extensibility (E) increased, and ratio figure R/E increased.GOD and TGase strengthened a fresh dough (non-frozen dough) structure. The starch granules embedded in the gluten network. After 35 days of frozen storage at -18℃, the gluten matrix in the control dough appeared less continuous, more disrupted, and separated from the starch granules, and the gluten film was also thinner. Dough with GOD and dough with TGase had a less fractured gluten network. Dough development height decreased with frozen storage. The GOD and TGase used had a positive effect on proof time, specific volume, and crumb firmness. Even if frozen storage temperature changed greatly, frozen doughs still had good storage steadier. Bread specific volume was biger compared to control.The effects of GOD and TGase on wheat proteins in dough were investigated using SDS-PAGE. The addition of GOD and TGase led to the crosslinking of the albumins and globulins. The effect of GOD on gliadins did not obvious. But TGase had significant effect on gliadins. The glutenins were cross-linked by the GOD and TGase treatment. The presence of very large polymers unable to stacking and separating gel formed proteins band.