Effect of Whey Protein Isolate on Dough and Bread Characteristics
Effect of blending 1 to 3% undenatured or denatured whey protein isolate (NWPI or DWPI) with wheat flour on dough rheology and baking characteristics of bread was studied. Wet Gluten (WG) and Gluten Index (GI) were also used to assess the effect of NWPI or DWPI on flour gluten. WG, GI, farinograph water absorption (WA), degree of dough softening (DOS), overpressure (P), configuration ratio (P/L), deformation energy (W) and bread volume (BV) decreased significantly (P < 0.05) with increasing amount of NWPI. Insignificant change (P > 0.05) was obtained for dough development time (DDT), dough stability (DS) and average abscissa to rupture (L) when either NWPI or DWPI was incorporated. There were significant interactions (P < 0.05) between configurations (NWPI or DWPI) and levels (1 to 3%) of WPI for all dough properties assessed, except for P/L and BV (P > 0.05). Furthermore, baking results also illustrated that firmness of crumbs increased with increasing levels of NWPI whereas breads containing DWPI gave soft crumbs. All breads, including control (without WPI) had coarse cell structures. A slight darkening of the crust was obtained in breads containing WPI compared to the control.
Keywords: whey, flour, rheology, dough, baking, bread