WAFER BATTERS - A RHEOLOGICAL STUDY

The performance of single wheat varieties in the production of wafer batters at a constant solids content has been studied. Following a standard mixing procedure dynamic oscillatory measurements were performed to obtain the phase angle and the elastic and viscous moduli. The effect of shear rate on batter viscosity was monitored as a function of increasing shear rate. Batters were centrifuged to obtain batter liquor, the liquid fraction of the batter mix, and its surface properties characterised. Surface tension values were measured and the surface theology of the films formed at the air-batter liquor interface determined using an oscillating ring surface shear rheometer. Compositional information of the batter liquor phase has been obtained using thin layer and gas chromatography. There was no direct relationship between the surface properties of the batter liquor and standard tests of wafer batter performance. Hard milling wheat varieties produced batters with stronger theological properties than soft milling varieties. The bulk elastic moduli of the batters were correlated with the hydration of gluten proteins. The dispersion of gluten proteins was found to be dependent upon the phase angle of the batter. Low phase angle values, ie greater dominance of elastic properties, led to increased gluten dispersion times and potential difficulties in production.