Influence of egg type, pressure and mode of incorporation on density and bubble distribution of a lady finger batter

Lady finger batter is a dispersed media where the continuous phase is the non-aerated batter and the dispersed phase is air. The influence of three important process variables (egg type, mode of incorporation of the ingredients, and operating pressure in the mixer) on two main characteristics of lady finger batter, i.e. density and bubble distribution, was studied. Three pasteurised whole egg types were studied: frozen, refrigerated and spray-dried. Two levels of pressure (105 Pa and 1.4 × 105 Pa) and two modes of incorporation (one and two stages) were considered. It was shown that the effect of aeration depended on the incorporation mode. For the “all-in” incorporation mode, density decreased and more bubbles were formed after the aeration step, regardless of egg type. Using the 1.4 × 105 Pa pressure gave more numerous, larger and more heterogeneous bubbles compared to 105 Pa. Finally, the best conditions to maximise overrun (24.3%) were 1.4 × 105 Pa, “all-in”, and frozen eggs, but relative span and Sauter diameter remained high (0.83 and 46 μm, respectively). On the other hand, the best conditions to minimise bubble size (Sauter diameter = 25 μm) and relative span (0.59) were 105 Pa, “all-in” mode, and dried eggs, but in these conditions, the overrun remained low, at 7.5%.