Effects of chemical and enzymatic modification on dough rheology and biscuit characteristics

The effect of addition of sodium meta-bisulfite and a commercial protease on dough rheological properties and biscuit characteristics was studied on 7 biscuit wheat cultivars. Sodium meta-bisulfite (SMS) (360 mg/kg flour) or protease (300 mg/kg flour) was added to semisweet biscuit dough. Rheological studies included creep recovery and shear oscillation. SMS and protease increased maximum strain, recovery strain, and phase tano, and lowered storage modulus, G′, and the relative recovery, % recovery. The effects varied among cultivars and between SMS and protease. Biscuit eccentricity (width/length) was significantly reduced by addition of SMS or protease, but the effect varied among the cultivars, and between SMS and protease. Partial least squares regression analysis of the rheological parameters and the dimensional characteristics showed that biscuit contraction and spread were mostly correlated to % recovery of the dough, and protein and gluten content of the flour. Correlations between predicted and measured contraction and spread were r = 0.70 and r = 0.43, respectively.