Diffusion-controlled shrinkage and growth of an air bubble entrained in water and in wheat flour particles.

Prior to an analysis of the shrinkage and growth of air bubbles entrained in wheat flour dough, the shrinkage and growth under a temperature rise of a small bubble in water was analysed for comparison.The rates of shrinkage and growth of the bubble were respectively controlled by the diffusion of under-and over-saturated dissolved air from and into the bubble.The diffusion coefficient of the dissolved air in water calculated from the shrinkage of the bubble was 2.10x 10~9m2/sec (17°C), which agrees with the literature value.