This investigation examines the ability of eggs to hold air and focuses in particular on egg white foams.

The investigation enables students to:

• Consider the method by which egg white foam is obtained.
• Observe the changes in egg white as foaming proceeds.
• Recognise optimum foaming for meringue formation.
• Examine the effects of methods by which sugar is incorporated into an egg white foam.
• Utilise hedonic ranking as a means of sensory evaluation.

Practical notes

It is desirable to produce a cooked base which utilises the egg yolk, is quick to prepare and cook and which can support the meringues. The recipe is a suggestion only, since other pudding bases may be developed according to personal tastes and individual recipe ideas.

Each pair should produce all six variants or, if time does not allow, the work can be allocated between the pairs of students. It is essential that all six variants are available for assessment.

An aluminium basin must not be used for whisking of egg whites since a discoloured foam will be produced.

It is essential that students recognise the end point of whisking in foam formation. The test involving inversion of the bowl should be demonstrated. This will ensure uniformity and avoid disaster.

The evaluation uses hedonic ranking. Only a 1-5 scale is suggested although a 1-9 scale may be substituted if a more detailed analysis is required; especially since students have experienced hedonic ranking on a five-point scale in Investigation 2.

In order to determine the success of the meringue topping, some discussion may be required which identifies the desirable attributes of a meringue used in this type of recipe.