fat crystal adsorption onto air bubbles during mixing
creates a continuous protein layer between the aire
water interface and the fat crystals (Fig. 4).
The fat crystals
are thus in direct contact with the air. When such batter is
heated, the fat crystals melt, and the resulting oil runs over
the inside surface of the bubble, eventually to form a uniform
layer (Fig. 4) (Brooker, 1993), which is then available
for incorporation into the surface of the expanding bubble
and which allows air bubbles to expand during baking without
rupturing (Shepherd & Yoell, 1976).