Air inclusion into a model cake batter using a pressure whisk: Development of gas hold-up and bubble size distribution

This paper investigates the development of gas hold-up (that is, gas volume fraction) and bubble size distribution in a model cake batter, which is aerated in a pressure whisk. With increasing aeration time, the hold-up was found to pass through a maximum before approaching a uniform steady state value. A mathematical model that describes this profile has been developed. Bubble size distribution was found to be adequately described by a log normal distribution function with mean size varying between 20 and 50 mum. Higher pressures were found to increase hold-up and mean bubble size, whereas higher whisk speeds reduced the time required to achieve a given hold-up and the final mean bubble size.